https://embryology.med.unsw.edu.au/embryology/api.php?action=feedcontributions&feedformat=atom&user=Z3212774 2026-05-13T12:43:18Z User contributions MediaWiki 1.39.10 https://embryology.med.unsw.edu.au/embryology/index.php?title=Advanced_-_Molecular_Development&diff=17021 2010-03-14T02:10:18Z

<p>Z3212774: </p> <hr /> <div>[[Image:Advancedicon.jpg|left|70px|link=Advanced_Cardiac_Embryology]]<br /> {{Advanced Cardiac menu}}<br /> <br /> {{Template:Cardiac_modules}}<br /> <br /> [[Image:Advanced Heart Development Timeline.jpg|center|850px]]<br /> <br /> <br /> In attempts to determine the molecular mechanisms controlling heart development, scientists have focussed on early cardiomyocyte development including the cellular movement of cardiomyocyte progenitors and the signaling mechanisms that regulate cardiomyogenesis from the blastula to gastrula stages as well as the morphological changes that occur later in development such as looping and septation. Some of the molecular and genetic factors regulating cardiac development have been previously described in this module in the aspect of development they pertain to. The following diagram provides an overview to the steps in cardiac development and the important associated genes, transcription factors and signalling molecules. Underneath this is a list of some of the predominant molecular pathways contributing to cardiac development.<br /> <br /> <br /> [[Image:Molecular &amp; Genetic Cardiac Development Factors.jpg|thumb|upright=3|center]]<br /> <br /> ===Transcription Factors===<br /> *Nk family transcription factors are expressed in all animals with contractile vascular cells and hence are crucial for myocardial development; Nkx2.5 is specifically required for left ventricular chamber development.<br /> *Gata family transcription factors interact with Nk factors to promote differentiation of cardiomyocytes, smooth muscle cells and endoderm; Gata4 regulates myocardial expression and is required for fusion of the heart tubes in the ventral midline; Gata5 is required for endocardial differentiation.<br /> *T-box genes play an important role in cardiac morphogenesis; Tbx1 may play a role in neural crest proliferation/function; Tbx2 plays a significant role in chamber specification; Tbx5 is required for atrial septation.<br /> *Pitx2 is a left-sided transcription factor that controls normal cardiac morphogenesis by regulating cell proliferation.<br /> <br /> ===Signalling Molecules===<br /> *'''Bone morphogenetic protein''' (particularly Bmp2) is expressed in cardiogenic mesoderm and is important for specification and myocardial differentiation.<br /> *'''Wnt''' signalling inhibition promotes cardiogenesis in the cardiogenic mesoderm.<br /> *'''Fibroblast growth factor''' (Fgf) acts alongside Bmp to allow for myocardial differentiation. Fgf8 is expressed in cardiogenic mesoderm and hence allows for cardiac specification.<br /> *'''Notch''' signalling establishes sub-populations within the cardiogenic mesoderm by regulating asymmetric cell division. Notch also has an inhibitory effect on myocardial differentiation.<br /> *'''Cripto''' mediates Nodal signalling to allow for myocardial differentiation.<br /> <br /> <br /> {| width=&quot;30%&quot; <br /> |-<br /> |bgcolor=&quot;#FF6666&quot;|&lt;big&gt;'''[[Advanced_-_Abnormalities|Back to Developmental Abnormalities]]'''&lt;/big&gt;<br /> |}</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=File:Molecular_%26_Genetic_Cardiac_Development_Factors.jpg&diff=17020 2010-03-14T02:09:18Z

<p>Z3212774: category:Heart ILP Identification of the predominant molecular and genetic factors involved in cardiac development.</p> <hr /> <div>[[category:Heart ILP]]<br /> Identification of the predominant molecular and genetic factors involved in cardiac development.</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=Advanced_-_Abnormalities&diff=17019 2010-03-14T02:07:09Z

<p>Z3212774: </p> <hr /> <div>[[Image:Advancedicon.jpg|left|70px|link=Advanced_Cardiac_Embryology]]<br /> {{Advanced Cardiac menu}}<br /> <br /> {{Template:Cardiac_modules}}<br /> <br /> [[Image:Advanced Heart Development Timeline.jpg|center|850px]]<br /> <br /> <br /> Congenital Heart Disease (CHD) is a broad term for a variety of cardiac and vasculature pre-natal defects. They affect about 8-10 of every 1,000 births in the United States. This increases considerably to 75 in 1,000 births if trivial lesions are included and even more so in those stillborn or spontaneously aborted. Cardiovascular abnormalities are the most common form of birth defect, comprising around 20% of all congenital malformations. In addition, given the increasing survival of patients with CHD, treated or untreated, it is expected that large numbers of adults will maintain CHD in the future. Hence CHD becomes a significant part of the clinical environment. The table below outlines some of the common obstructive, septal and hypoplastic defects in order of their incidence.<br /> <br /> <br /> {|style=&quot;width:75%&quot; align=center<br /> |-style=&quot;background:steelblue&quot;<br /> !Diagram<br /> !Abnormality<br /> !Epidemiology<br /> !Description<br /> |-<br /> |[[Image:Ventricular Septal Defect.jpg|thumb|x100px|VSD]]<br /> |'''Ventricular Septal Defect'''<br /> |25% of CHD; more frequent in males<br /> |Result from growth failure of the membranous IV septum or endocardial cushions leading to a lack of closure of the IV foramen. Many VSDs are actually from defects in the outflow tract septum. 30-50% close spontaneously; large VSDs result in dyspnoea and cardiac failure in infancy.<br /> |-style=&quot;background:lightsteelblue&quot;<br /> |[[Image:Tetralogy of Fallot.jpg|thumb|x100px|Tetralogy of Fallot]]<br /> |'''Tetralogy of Fallot'''<br /> |9-14% of CHD<br /> |Comprises a classic group of four defects: pulmonary stenosis, VSD, dextroposition of the aorta and right ventricle hypertrophy. An additional ASD creates a ‘pentalogy’ of Fallot. Results in cyanosis.<br /> |-<br /> |[[Image:Transposition of the Great Vessels.jpg|thumb|x100px|Transposition of the Great Vessels]]<br /> |'''Transposition of the Great Vessels'''<br /> |10-11% of CHD<br /> |The most common form of transposition is where the aorta arises from the right ventricle while the pulmonary trunk arises from the left. This occurs either via abnormal rotation of the arterial pole or abnormal development of the outflow septum. In order for a newborn to survive prior to surgery there must be mixing of systemic and pulmonary circulations through a VSD, ASD or patent ductus arteriosus. It is the most common cause of cyanotic heart disease in newborns and is surgically corrected.<br /> |-style=&quot;background:lightsteelblue&quot;<br /> |[[Image:Atrial Septal Defect.jpg|thumb|x100px|ASD]]<br /> |'''Atrial Septal Defect'''<br /> |6-10% of CHD; more common in females<br /> |The atrial septal myocardium is derived from multiple sources making various places susceptible to defects. The most common is a patent foramen ovale. Others include an ostium secundum defect and ostium primum defect (where there is usually some defect with the AV cushions as well). Defects in the sinus venosus act as ASDs yet are really defects in the wall separating the right pulmonary veins and SVC. A common atrium results from a complete lack of atrial septation. ASDs results in cyanosis due to a right-to-left shunt.<br /> |-<br /> |[[Image:Pulmonary Atresia.jpg|thumb|x100px|Pulmonary Atresia]][[Image:Pulmonary Stenosis.jpg|thumb|x100px|Pulmonary Stenosis]]<br /> |'''Pulmonary Atresia &amp; Pulmonary Stenosis'''<br /> |10% of CHD<br /> |Unequal division of trunks causes cusps to fuse to form a dome with a narrow/non-existent lumen and hence obstruction to blood flow from the right ventricle to the pulmonary artery. The most common side of stenosis/obstruction is at the pulmonary valve itself (rather than distal or proximal to the valve). Heart-lung transplantation may be the only therapy.<br /> |-style=&quot;background:lightsteelblue&quot;<br /> |[[Image:Patent Ductus Arteriosus.jpg|thumb|x100px|Patent Ductus Arteriosus]]<br /> |'''Patent Ductus Arteriosus'''<br /> |6-8% of CHD; 2-3 times more common in females; common in preterm newborns<br /> |Failure of contraction of the muscular wall of the DA. This imposes greater pressure on the pulmonary circulation. Many will close spontaneously, however if this does not occur, surgical closure is advised to prevent the development of congestive heart failure.<br /> |-<br /> |[[Image:Aortic Stenosis.jpg|thumb|x100px|Aortic Stenosis]]<br /> |'''Aortic Stenosis'''<br /> |7% of CHD<br /> |Stenosis is caused either by a muscular obstruction below the aortic valve, obstruction at the valve itself or aortic narrowing above the valve. The most common site is at the valve itself which results from a persistence of endocardial tissue that normally degenerates. Results in LV hypertrophy and heart murmurs.<br /> |-style=&quot;background:lightsteelblue&quot;<br /> |[[Image:Hypoplastic Left Heart.jpg|thumb|x100px|Hypoplastic Left Heart]]<br /> [[Image:Functional Hypoplastic Left Heart.jpg|thumb|x100px|Functional Hypoplastic Left Heart]]<br /> |'''Hypoplastic Left Heart Syndrome'''<br /> |4-8% of CHD<br /> |The left ventricle is incapable of supporting the systemic circulation, hence the right ventricle maintains both pulmonary and systemic circulations aided by an ASD. Other defects such as stenosis or atresia of the mitral and aortic valves, anomalous pulmonary venous connections and hypoplasia of the aortic arch can be responsible for hypoplastic left heart syndrome. Infants usually die within weeks.<br /> |-<br /> |[[Image:Coarctation of the Aorta.jpg|thumb|x100px|Coarctation of the Aorta]]<br /> |'''Coarctation of the Aorta'''<br /> |5-7% of CHD<br /> |Aortic constriction in the region of the ductus arteriosus. It is associated with patent ductus arteriosus, VSD and aortic stenosis. Closure of the ductus arteriosus in neonates with a coarctation imposes a greater afterload on the left ventricle which can lead to congestive heart failure. Treatment aims at maintaining the ductus arteriosus via prostaglandins.<br /> |-style=&quot;background:lightsteelblue&quot;<br /> |[[Image:Partial Anomalous Pulmonary Venous Drainage.jpg|thumb|x100px|PAPVD]][[Image:Total Anomalous Pulmonary Venous Connection.jpg|thumb|x100px|TAPVC]]<br /> |'''Partial/Total Anomalous Pulmonary Venous Connection'''<br /> |&lt;4% of CHD; more common in females<br /> |In partial anomalous pulmonary venous drainage (PAPVD) a portion of the pulmonary venous blood flow returns to the right atrium. When over 50% of the veins return to the right atrium the condition is clinically significant. All types of total anomalous pulmonary venous connection (TAPVC) (those compatible with survival) are accompanied by an atrial septal defect. Pulmonary veins in TAPVC tend to open into one of the systemic veins before returning to the right atrium. The overloaded pulmonary circuit leads to cyanosis, tachypnoea and dyspnoea. Treatment is via surgical redirection.<br /> |-<br /> |[[Image:Tricuspid Atresia.jpg|thumb|x100px|Tricuspid Atresia]]<br /> |'''Tricuspid Atresia'''<br /> |1-3% of CHD<br /> |Complete lack of formation of the tricuspid valve which results in an hypoplastic right ventricle. The pulmonary circulation can be maintained via a VSD, and an ASD is necessary for survival. Results in cyanosis and tachypnoea. Treatment is initially via administration of prostaglandins followed by surgery to place a shunt to maintain the pulmonary circulation.<br /> |-style=&quot;background:lightsteelblue&quot;<br /> |[[Image:Double Outlet Right Ventricle.jpg|thumb|x100px|DORV]]<br /> |'''Double Outlet Right Ventricle'''<br /> |1-1.5% of CHD<br /> |Both large arteries arise wholly or mainly from the right ventricle. This defect is considered to be present if the aorta obtains 50% of its blood from the right ventricle. The defect arises due to absence of the secondary heart field such that myocardium is not added to the outflow tract during looping. Arrangement of the atrioventricular valves, coronary arteries and the ventriculoarterial connections as well as clinical manifestations are variable.<br /> |-<br /> |[[Image:Interrupted Aortic Arch.jpg|thumb|x100px|Interrupted Aortic Arch]]<br /> |'''Interrupted Aortic Arch'''<br /> |Very rare<br /> |An extreme form of coarctation of the aorta involving a gap in the ascending or descending thoracic aorta that results from abnormal proliferation/migration/function of neural crest cells. Different types of interrupted aortic arch are defined based on their relation to the arterial branches of the aortic arch. It is greatly associated with other defects such as a patent ductus arteriosus or VSD. It is treated with prostaglandin to maintain ductus arteriosus followed by surgery.<br /> |}<br /> <br /> <br /> {| width=&quot;100%&quot;<br /> |-<br /> |width=&quot;30%&quot; bgcolor=&quot;#FF6666&quot;|&lt;big&gt;'''[[Advanced_-_Cardiac_Conduction|Back to the Conduction System]]'''&lt;/big&gt;<br /> |<br /> |width=&quot;30%&quot; bgcolor=&quot;#FF6666&quot; align=&quot;right&quot;|&lt;big&gt;'''[[Advanced_-_Molecular_Development|Next: Molecular Control]]'''&lt;/big&gt;<br /> |-<br /> |bgcolor=&quot;gold&quot;|&lt;big&gt;'''[[Intermediate_-_Cardiac_Abnormalities|Go to this section in the intermediate level]]'''&lt;/big&gt;<br /> |<br /> |<br /> |}</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=File:Cardiac_Conduction_System.jpg&diff=17018 2010-03-14T02:03:43Z

<p>Z3212774: category:Heart ILP Cardiac conduction system in the adult heart.</p> <hr /> <div>[[category:Heart ILP]]<br /> <br /> Cardiac conduction system in the adult heart.</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=Advanced_-_Cardiac_Conduction&diff=17017 2010-03-14T02:03:25Z

<p>Z3212774: </p> <hr /> <div>[[Image:Advancedicon.jpg|left|70px|link=Advanced_Cardiac_Embryology]]<br /> {{Advanced Cardiac menu}}<br /> <br /> {{Template:Cardiac_modules}}<br /> <br /> [[Image:Advanced Heart Development Timeline.jpg|center|850px]]<br /> <br /> <br /> Cardiac conduction in the adult heart begins in the sinoatrial (SA) node which is located at the junction between the SVC and the right atrium. The impulses generated here spread through the atria, initiating contraction. The impulses travel to the atrioventricular (AV) node which acts to slow the transmission of an impulse between the atria and ventricles. After this time lag, impulses travel to the ventricles via the common atrioventricular bundle (bundle of His) to the bundle branches in the IV septum. The branches split and terminate throughout the myocardium in a network of Purkinje fibres. The adult conduction system is shown below.<br /> <br /> [[Image:Cardiac Conduction System.jpg|thumb|center|upright=2|Diagram of the adult cardiac conduction system]]<br /> <br /> ===Development of the conduction system===<br /> Cardiomyocytes in the caudal heart tube are the first to become electrically active and become the “pacemaker”. The SA node, which develops during the fifth week, initially develops in the sinus venosus and then is incorporated into the RA. The AV node arises slightly superior to the endocardial cushions. Fibres forming the bundle of His develop from fast-conducting ventricular myocardium while the SA and AV nodes are formed from the slow-conducting myocardium of the inflow tract and AV canal. Connective tissue grows in from the epicardium, forming the cardiac skeleton that separates conduction in the atria and ventricles.<br /> <br /> <br /> {| width=&quot;100%&quot;<br /> |-<br /> |width=&quot;30%&quot; bgcolor=&quot;#FF6666&quot;|&lt;big&gt;'''[[Advanced_-_Valve_Development|Back to Valves]]'''&lt;/big&gt;<br /> |<br /> |width=&quot;30%&quot; bgcolor=&quot;#FF6666&quot; align=&quot;right&quot;|&lt;big&gt;'''[[Advanced_-_Abnormalities|Next: Developmental Abnormalities]]'''&lt;/big&gt;<br /> |}</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=Advanced_-_Valve_Development&diff=17016 2010-03-14T02:01:03Z

<p>Z3212774: </p> <hr /> <div>[[Image:Advancedicon.jpg|left|70px|link=Advanced_Cardiac_Embryology]]<br /> {{Advanced Cardiac menu}}<br /> {{Template:Cardiac_modules}}<br /> <br /> [[Image:Advanced Heart Development Timeline.jpg|center|850px]]<br /> <br /> <br /> [[Image:AV Canal Division (Superior View).jpg|thumb|right|upright=2]][[Image:AV Valves.jpg|thumb|right|upright=2|Development of the mitral and tricuspid valves]]Many of the mechanisms involved in the development of cardiac valves, particularly the process of epithelial to mesenchymal transformation (EMT), are poorly understood. Much of valve formation revolves around expansion of endocardial cushion tissue, yet limitation of cell proliferation is vital in ensuring the cushion swellings can be remodelled to form thin sheets. EMT, which allows for cushion proliferation, is limited by neurofibromin acting through the inhibition of Ras signalling as well as Smad6 which interferes with TGFβ signalling.<br /> <br /> <br /> The AV valves begin to form between the fifth and eighth weeks of development. The valve leaflets are attached to the ventricular walls by thin fibrous chords: the chordae tendineae, which insert into small muscles attached to the ventricle wall: the papillary muscles. These structures are sculpted from the ventricular wall. The left AV valve has anterior and posterior leaflets and is termed the bicuspid or mitral valve. The right AV valve has a third, small septal cusp and thus is called the tricuspid valve. These concepts are depicted on the right.<br /> <br /> <br /> [[Image:Semilunar Valves.jpg|thumb|left|upright=2|Development of the semilunar valves]]<br /> [[Image:Semilunar Cusps.jpg|thumb|left|upright=2|Development of the semilunar cusps]]<br /> <br /> The aortic and pulmonary valves, termed the semilunar valves, are formed from the bulbar ridges and subendocardial valve tissue. The primordial semilunar valve consists of a mesenchymal core covered by endocardium. Excavation occurs, thinning the valve tissue thus creating its final shape (see left). These valves form the four valves of the adult heart depicted below. The mechanisms of valve remodelling in these final steps in both the AV and semilunar valves are not fully understood yet are thought to involve apoptotic pathways.<br /> <br /> <br /> {| width=&quot;100%&quot;<br /> |-<br /> |width=&quot;30%&quot; bgcolor=&quot;#FF6666&quot;|&lt;big&gt;'''[[Advanced_-_Outflow_Tract|Back to Outflow Tract]]'''&lt;/big&gt;<br /> |<br /> |width=&quot;30%&quot; bgcolor=&quot;#FF6666&quot; align=&quot;right&quot;|&lt;big&gt;'''[[Advanced_-_Cardiac_Conduction|Next: Conduction System]]'''&lt;/big&gt;<br /> |-<br /> |bgcolor=&quot;gold&quot;|&lt;big&gt;'''[[Intermediate_-_Heart_Valves|Go to this section in the intermediate level]]'''&lt;/big&gt;<br /> |<br /> |<br /> |}</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=Advanced_-_Outflow_Tract&diff=17015 2010-03-14T01:59:40Z

<p>Z3212774: </p> <hr /> <div>[[Image:Advancedicon.jpg|left|70px|link=Advanced_Cardiac_Embryology]]<br /> {{Advanced Cardiac menu}}<br /> {{Template:Cardiac_modules}}<br /> <br /> [[Image:Advanced Heart Development Timeline.jpg|center|850px]]<br /> <br /> <br /> [[Image:Outflow Tract Division (Cross-Section).jpg|thumb|right|upright=1.5|Cross-sections of the outflow tract illustrating the truncal and bulbar ridges]]Cardiac neural crest originates between somites 1 and 3 of the neural tube and migrates through the pharyngeal arches to contribute to the conotruncal septum. Active proliferation of pharyngeal mesenchymal cells in the bulbus cordis during the fifth week creates bulbar ridges which are continuous in the truncus arteriosus (see image to the right). The cardiac neural crest migrates into these ridges, condensing as cellular columns to support the outflow tract septum. The ridges form a 180° spiral to create the helical aorticopulmonary septum. Myocardialisation of the ridges gives a zippering effect resulting in fusion. Fusion occurs in a distal to proximal direction during the sixth week, allowing for cleavage of the aorta and pulmonary trunk. The spiralling nature of the ridges causes the pulmonary trunk to twist around the aorta. The bulbus cordis accounts for the smooth conus arteriosus (or infundibulum) in the right ventricle and the aortic vestibule in the left ventricle. The animation below depicts the septation of the outflow tract.<br /> <br /> <br /> <br /> &lt;Flowplayer height=&quot;564&quot; width=&quot;720&quot; autoplay=&quot;false&quot;&gt;outflow_tract_001.flv&lt;/Flowplayer&gt;<br /> <br /> <br /> The outflow tract is one of the most common sites of cardiac abnormalities, as it requires normal development and proliferation of multiple cell types. Abnormalities commonly occur via defects in the following areas:<br /> *Anterior/secondary heart field - abnormal contribution/proliferation leads to an elongation defect<br /> *Neural crest cells - abnormal migration/proliferation leads to a septation defect<br /> *Myocardium - abnormal rotation/laterality leads to an alignment defect<br /> *Endocardium - abnormal EMT/proliferation leads to a cushion defect<br /> These abnormalities are consequently expressed as a host of disorders involving the conotruncal region such as common arterial trunk, double outlet right ventricle, interrupted aortic arch, transposition of the great arteries, tetralogy of fallot and ventricular septal defect.<br /> <br /> <br /> {| width=&quot;100%&quot;<br /> |-<br /> |width=&quot;30%&quot; bgcolor=&quot;#FF6666&quot;|&lt;big&gt;'''[[Advanced_-_Cardiac_Septation|Back to Septation]]'''&lt;/big&gt;<br /> |<br /> |width=&quot;30%&quot; bgcolor=&quot;#FF6666&quot; align=&quot;right&quot;|&lt;big&gt;'''[[Advanced_-_Valve_Development|Next: Valve Development]]'''&lt;/big&gt;<br /> |-<br /> |bgcolor=&quot;gold&quot;|&lt;big&gt;'''[[Intermediate_-_Outflow_Tract|Go to this section in the intermediate level]]'''&lt;/big&gt;<br /> |<br /> |<br /> |}</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=Advanced_-_Cardiac_Septation&diff=17014 2010-03-14T01:58:21Z

<p>Z3212774: </p> <hr /> <div>[[Image:Advancedicon.jpg|left|70px|link=Advanced_Cardiac_Embryology]]<br /> {{Advanced Cardiac menu}}<br /> {{Template:Cardiac_modules}}<br /> <br /> [[Image:Advanced Heart Development Timeline.jpg|center|850px]]<br /> <br /> <br /> All of the partitioning of the primitive heart occurs between the middle of the fourth week and the end of the fifth week. Division of the atrioventricular canal is described below while septation of the atria and ventricles is described [[Advanced_-_Cardiac_Septation_2|here]]. <br /> <br /> ===Division of the AV Canal===<br /> Two endocardial cushions form on the dorsal and ventral surfaces of the AV canal. Following expansion of the cardiac jelly, epithelial to mesenchymal transformation (EMT) of the endocardial cells in the canal occurs forming the cushions. Synergistic signalling between BMP and TGFβ facilitates EMT. The cushions grow as they are invaded by mesenchymal cells from the endocardium during the fifth week, eventually fusing to create the right and left AV canals, hence partially separating the primitive atrium and ventricle.<br /> <br /> &lt;Flowplayer height=&quot;564&quot; width=&quot;720&quot; autoplay=&quot;false&quot;&gt;Heart septation 001.flv&lt;/Flowplayer&gt;<br /> <br /> <br /> {| width=&quot;100%&quot;<br /> |-<br /> |width=&quot;30%&quot; bgcolor=&quot;#FF6666&quot;|&lt;big&gt;'''[[Advanced_-_Cardiac_Looping|Back to Looping]]'''&lt;/big&gt;<br /> |<br /> |width=&quot;30%&quot; bgcolor=&quot;#FF6666&quot; align=&quot;right&quot;|&lt;big&gt;'''[[Advanced_-_Cardiac_Septation_2|Next: Cardiac Septation 2]]'''&lt;/big&gt;<br /> |-<br /> |bgcolor=&quot;gold&quot;|&lt;big&gt;'''[[Intermediate_-_Atrial_Ventricular_Septation|Go to this section in the intermediate level]]'''&lt;/big&gt;<br /> |<br /> |<br /> |}</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=Advanced_-_Cardiac_Looping&diff=17013 2010-03-14T01:56:41Z

<p>Z3212774: </p> <hr /> <div>[[Image:Advancedicon.jpg|left|70px|link=Advanced_Cardiac_Embryology]]<br /> {{Advanced Cardiac menu}}<br /> {{Template:Cardiac_modules}}<br /> <br /> [[Image:Advanced Heart Development Timeline.jpg|center|850px]]<br /> <br /> <br /> Cardiac looping occurs from late in the fourth week to early in the fifth week and has been studied in great detail in chick embryos whose initial, straight heart tube is representative of that developing in humans. There are two animations showing advanced cardiac looping. The first is shown below and represents heart looping from a ventral view. The [[Advanced_-_Cardiac_Looping_2|second animation of cardiac looping]] shows the heart looping from a left, lateral perspective. A written description of the process is outlined below.<br /> <br /> <br /> &lt;Flowplayer height=&quot;540&quot; width=&quot;720&quot; autoplay=&quot;false&quot;&gt;Heart looping 006.flv&lt;/Flowplayer&gt;<br /> <br /> The second stage of looping, creating an S-shape, occurs as the ventricular bend moves caudally and the distance between the outflow and inflow tracts diminishes. At this time the dorsal mesocardium degenerates, forming the transverse pericardial sinus (a point of communication across the pericardial coelom). In addition, the atrial and outflow poles converge and myocardial cells are added, forming the truncus arteriosus. The final stage of cardiac looping is the wedging of the aorta between the atrioventricular (AV) valves. This occurs during septation and is dependent on the retraction and rotation of the myocardium by 45°.<br /> <br /> ===Left-Right Asymmetry===<br /> The heart is the first organ in the body to express left-right asymmetry in the form of looping. The left-right axis of the heart is established during gastrulation. Shh is expressed in the left side of Henson’s node in the primitive streak but is inhibited by the activation of Activin IIa receptors in the right. Shh leads to the expression of Nodal and Pitx2 in the left sided mesoderm. Pitx2 expressed in the left side of the heart tube is then responsible for asymmetric organogenesis.<br /> <br /> <br /> {| width=&quot;100%&quot;<br /> |-<br /> |width=&quot;30%&quot; bgcolor=&quot;#FF6666&quot;|&lt;big&gt;'''[[Advanced_-_Heart_Tubes|Back to the Heart Tubes]]'''&lt;/big&gt;<br /> |<br /> |width=&quot;30%&quot; bgcolor=&quot;#FF6666&quot; align=&quot;right&quot;|&lt;big&gt;'''[[Advanced_-_Cardiac_Septation|Next: Cardiac Septation]]'''&lt;/big&gt;<br /> |-<br /> |bgcolor=&quot;gold&quot;|&lt;big&gt;'''[[Intermediate_-_Heart_Tube_Looping|Go to this section in the intermediate level]]'''&lt;/big&gt;<br /> |<br /> |<br /> |}</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=Advanced_-_Heart_Tubes&diff=17012 2010-03-14T01:54:03Z

<p>Z3212774: </p> <hr /> <div>[[Image:Advancedicon.jpg|left|70px|link=Advanced_Cardiac_Embryology]]<br /> {{Advanced Cardiac menu}}<br /> <br /> {{Template:Cardiac_modules}}<br /> <br /> [[Image:Advanced Heart Development Timeline.jpg|center|850px]]<br /> <br /> <br /> At approximately day 19 the lateral plate mesoderm divides into dorsal (somatic) and ventral (splanchnic) layers, forming the pericardial coelom between them. Angioblastic cords develop in the splanchnic mesoderm and canalise to form bilateral heart tubes. Following lateral folding of the embryo, fusion of the heart tubes occurs, beginning cranially and extending caudally. Folding of the heart of the embryo during the fourth week brings the heart tube dorsal to the pericardial cavity. The precardiomyocytes differentiate to form the myocardial sleeve of the heart tube, allowing the heart tube to begin beating. By the end of the fourth week (day 22) coordinated contractions of the heart tube, which push blood cranially, are present. This function initiates as nutritional and oxygen embryologic demands can no longer be met by passive diffusion from the placenta.<br /> <br /> <br /> The primordial myocardium forms from splanchnic mesoderm surrounding the pericardial coelom. It is separated from the endothelial heart tube by cardiac jelly (gelatinous connective tissue). The endothelium of the heart tube forms the internal endocardium, while the epicardium develops from mesothelial cells arising from the sinus venosus, which spread cranially over the myocardium. Recent knowledge shows that additional myocardial cells are added to the outflow tract during heart looping. The following animation shows the folding and fusion of the heart tubes.<br /> <br /> <br /> &lt;Flowplayer height=&quot;540&quot; width=&quot;720&quot; autoplay=&quot;false&quot;&gt;Heart folding 001.flv&lt;/Flowplayer&gt;<br /> <br /> <br /> {| width=&quot;100%&quot;<br /> |-<br /> |width=&quot;30%&quot; bgcolor=&quot;#FF6666&quot;|&lt;big&gt;'''[[Advanced_-_Heart_Fields|Back to Heart Fields]]'''&lt;/big&gt;<br /> |<br /> |width=&quot;30%&quot; bgcolor=&quot;#FF6666&quot; align=&quot;right&quot;|&lt;big&gt;'''[[Advanced_-_Cardiac_Looping|Next: Cardiac Looping]]'''&lt;/big&gt;<br /> |-<br /> |bgcolor=&quot;gold&quot;|&lt;big&gt;'''[[Intermediate_-_Primordial_Heart_Tube|Go to this section in the intermediate level]]'''&lt;/big&gt;<br /> |<br /> |<br /> |}</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=Advanced_-_Heart_Fields&diff=17011 2010-03-14T01:49:22Z

<p>Z3212774: </p> <hr /> <div>[[Image:Advancedicon.jpg|left|70px|link=Advanced_Cardiac_Embryology]]<br /> {{Advanced Cardiac menu}}<br /> {{Template:Cardiac_modules}}<br /> <br /> [[Image:Advanced Heart Development Timeline.jpg|center|850px]]<br /> <br /> <br /> The heart primordium arises predominantly from splanchnic mesoderm in the cardiogenic region of the trilaminar embryo. Blastodermal cardiogenic precursors have been located in the rostral epiblast either side of the primitive streak in multiple animal models. Cardiogenic precursors have also been located in the rostral primitive streak. After ingression through the primitive streak, mesodermal cells rapidly move laterally and cranially until they reach the cardiogenic fields. Studies in chicks define these cardiogenic areas as distinct bilateral fields in the cranial portion of the embryonic disc. However, studies using mice models repeatedly describe the cardiogenic area as a continuous horseshoe. The most likely explanation for this discrepancy is in the timing of mesodermal migration which occurs rapidly in mice such that distinct cardiogenic fields are indistinguishable. Thus the cardiogenic region can be thought of as bilateral fields that later merge cranially so that independent fields are no longer identifiable.<br /> <br /> The following animation shows the location of cardiogenic precursors in the epiblast that proceed to migrate through the primitive streak to form the mesodermal cardiogenic fields. The cells in the primitive streak are organised rostrocaudally, while after migration to form the cardiogenic fields they are organised mediolaterally. The most cranial end of the cardiogenic field becomes the ventral midline of the later heart tube which becomes the right border during looping.<br /> <br /> <br /> &lt;Flowplayer height=&quot;565&quot; width=&quot;720&quot; autoplay=&quot;false&quot;&gt;Heart fields 001.flv&lt;/Flowplayer&gt;<br /> <br /> <br /> ===Anterior and Secondary Heart Fields===<br /> The anterior heart field has been described and defined differently within different species and by different labs as: <br /> *In mice - the splanchnic mesoderm and mesodermal core of the pharyngeal arches which migrates to form the distal portion of the right ventricle and conus<br /> *In chicks - the mesenchyme surrounding the outflow tract and contributing to the addition of conotruncal myocardium.<br /> The secondary heart field has been described as pharyngeal mesenchyme that contributes myocardium and smooth muscle to the arterial pole.<br /> <br /> The cells from this field have been located medial to the originally defined cardiogenic fields. However, the existence of multiple heart fields has not been proven, as these cells may form a complex part of the original cardiogenic fields and there may be several cell populations in the cardiogenic fields with complex determination and development.<br /> <br /> {| width=&quot;100%&quot;<br /> |-<br /> |width=&quot;30%&quot; bgcolor=&quot;#FF6666&quot;|&lt;big&gt;'''[[Advanced_Cardiac_Embryology|Back to the Advanced Homepage]]'''&lt;/big&gt;<br /> |<br /> |width=&quot;30%&quot; bgcolor=&quot;#FF6666&quot; align=&quot;right&quot;|&lt;big&gt;'''[[Advanced_-_Heart_Tubes|Next: The Endocardial Heart Tubes]]'''&lt;/big&gt;<br /> |}</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=Intermediate_-_Vascular_Overview&diff=17010 2010-03-14T01:48:44Z

<p>Z3212774: </p> <hr /> <div>[[Image:Intermediateicon.jpg|left|70px|link=Intermediate_Cardiac_Embryology]]<br /> {{Template:Intermediate Cardiac menu}}<br /> <br /> <br /> {{Template:Cardiac_modules}}<br /> <br /> [[Image:Intermediate Heart Development Timeline.jpg|center|850px]]<br /> <br /> <br /> Some understanding of embryonic vascular development is helpful in a study of cardiac embryology and the embryonic circulation. Early in the third week of embryonic development vasculogenesis begins whereby endothelial cell precursors form aggregations as angioblastic cords. This process underlies the initial formation of the endocardial heart tubes as well as the primitive blood vessels. The cords coalesce to form blood vessels while continued angiogenesis, driven by metabolic requirements and specifically hypoxia, allows for the creation of a vascular network.<br /> <br /> ===Development of Arteries===<br /> <br /> [[Image:Aortic Arches (Drawing).jpg|thumb|right|upright=1.5|The aortic arches]]Upon folding of the embryo the paired dorsal aortae connecting to the cranial end of the heart tube are brought ventrally to form the first aortic arches. Additional aortic arches develop over the next few weeks which are later remodelled to form the arteries of the upper body. Caudal to the arches, the paired dorsal aortae fuse to form a single median dorsal aorta which develops the following branches:<br /> *Ventral (gut) branches - derived from the vitelline arteries<br /> *Lateral branches - supply retroperitoneal structures<br /> *Dorsolateral branches (intersegmental arteries) - supply the head, neck, body wall, limbs and vertebral column<br /> <br /> ===Development of Veins===<br /> <br /> Three paired veins drain into the primordial heart tube:<br /> *Vitelline veins - return poorly oxygenated blood from the yolk sac<br /> *Umbilical veins - carry well-oxygenated blood from the primordial placenta<br /> *Common cardinal veins - return poorly oxygenated blood from the body of the embryo<br /> The vitelline venous system gives rise to the liver sinusoids and portal system and forms the ductus venosus which acts as a shunt from the umbilical vein to the IVC. The IVC is formed during a left-to-right shift in the embryonic veins and is composed of:<br /> *A hepatic segment - from the hepatic vein and sinusoids<br /> *A prerenal segment - from the right subcardinal vein<br /> *A renal segment - from subcardinal and supracardinal anastomosis<br /> *A postrenal segment - from right supracardinal vein<br /> <br /> The following two diagrams give an overview to the embryonic vasculature:<br /> <br /> {|align=center<br /> |[[Image:Embryonic Circulations.jpg|thumb|center|upright=2|The three embryonic circulations]]<br /> |[[Image:Embryonic Cardiovascular System (Drawing).jpg|thumb|center|upright=2|The embryonic cardiovascular system]]<br /> |}<br /> <br /> ===Fetal Circulation===<br /> <br /> [[Image:Fetal Circulation Pathway.jpg|thumb|right|upright=2|Fetal circulation]]Fetal circulation consequently differs from the adult one predominantly due to the presence of 3 major vascular shunts:<br /> *Ductus venosus - between the umbilical vein and IVC<br /> *Foramen ovale - between the right and left atrium<br /> *Ductus arteriosus - between the pulmonary artery and descending aorta<br /> <br /> The main function of these shunts is to redirect oxygenated blood away from the lungs, liver and kidney (whose functions are performed by the placenta).<br /> <br /> Oxygenated blood is carried from the placenta to the foetus in the umbilical vein, most of which then passes through the ductus venosus to the IVC while some blood supplies the liver via the portal vein. Blood from the liver drains into the IVC through the hepatic veins. The blood in the IVC is a mixture of oxygenated blood from the umbilical vein and desaturated blood from the lower limbs and abdominal organs (e.g. the liver). This blood enters the right atrium where most of it is directed to the left atrium through the foramen ovale and from here to the left ventricle and aorta. The remainder of the blood in the right atrium passes with blood from the SVC (from the head and upper limbs) to the right ventricle and pulmonary artery where most of it passes to the aorta via the ductus arteriosus. The blood passes from the aorta to the hypogastric arteries, umbilical arteries and then back to the placenta.<br /> <br /> {| width=&quot;100%&quot;<br /> |-<br /> |width=&quot;30%&quot; bgcolor=&quot;gold&quot;|&lt;big&gt;'''[[Intermediate_-_Cardiac_Abnormalities|Back to Abnormalities]]'''&lt;/big&gt;<br /> |<br /> |width=&quot;30%&quot; bgcolor=&quot;#FF6666&quot; align=&quot;right&quot;|&lt;big&gt;'''[[Advanced_Cardiac_Embryology|Next: Begin Advanced Module]]'''&lt;/big&gt;<br /> |-<br /> |bgcolor=&quot;limegreen&quot;|&lt;big&gt;'''[[Basic_-_Vascular_Heart_Connections|Go to this section in the basic level]]'''&lt;/big&gt;<br /> |<br /> |<br /> |}<br /> <br /> {{Template:Glossary}}<br /> <br /> '''Angioblastic cords:''' Groups or ‘columns’ of embryonic precursor cells which will form the walls of both arteries and veins.<br /> <br /> '''Angiogenesis:''' Growth of new blood vessels.<br /> <br /> '''Aortic arch arteries:''' (Or pharyngeal arch arteries.) Each early developing pharyngeal arch contains a lateral pair of arteries arising from the aortic sac, above the heart, and running into the dorsal aorta. Later in development these arch arteries are extensively remodelled to form specific components of the vascular system.<br /> <br /> '''Dorsal aortae:''' Two largest arteries either side of the midline which later fuse to form the descending portion of the aorta.<br /> <br /> '''Hypoxia:''' Pathological condition in which part or all of the body suffers from inadequate oxygen supply.<br /> <br /> '''Retroperitoneal:''' Refers to abdominal organs located external to the peritoneal cavity.<br /> <br /> '''Vasculogenesis:''' Growth of blood vessels from endothelial precursor cells which migrate and differentiate to form blood vessels. Differs from angiogenesis which refers to the growth of blood vessels from pre-existing ones.<br /> <br /> [[category:heart]]</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=File:Embryonic_Cardiovascular_System_(Drawing).jpg&diff=17009 2010-03-14T01:39:39Z

<p>Z3212774: category:Heart ILP</p> <hr /> <div>[[category:Heart ILP]]</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=File:Aortic_Arches_(Drawing).jpg&diff=17008 2010-03-14T01:39:03Z

<p>Z3212774: category:Heart ILP</p> <hr /> <div>[[category:Heart ILP]]</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=Intermediate_-_Cardiac_Abnormalities&diff=17007 2010-03-14T01:36:25Z

<p>Z3212774: </p> <hr /> <div>[[Image:Intermediateicon.jpg|left|70px|link=Intermediate_Cardiac_Embryology]]<br /> {{Template:Intermediate Cardiac menu}}<br /> <br /> <br /> {{Template:Cardiac_modules}}<br /> <br /> [[Image:Intermediate Heart Development Timeline.jpg|center|850px]]<br /> <br /> <br /> Congenital Heart Disease (CHD) is a broad term for a variety of cardiac and vasculature prenatal defects. They affect about 8-10 of every 1,000 births in the United States. Heart and vascular abnormalities make up around 20% of all congenital malformations. Some of the more common abnormalities are outlined in the table below in order of frequency.<br /> <br /> <br /> {|style=&quot;width:75%&quot; align=center<br /> |-style=&quot;background:steelblue&quot;<br /> !Diagram<br /> !Abnormality<br /> !Epidemiology<br /> !Description<br /> |-<br /> |[[Image:Ventricular Septal Defect.jpg|100px]]<br /> |'''Ventricular Septal Defect'''<br /> |25% of CHD; more frequent in males<br /> |Growth failure of the membranous IV septum or endocardial cushions, resulting in a lack of closure of the IV foramen. 30-50% close spontaneously; large VSDs result in dyspnoea and cardiac failure in infancy.<br /> |-style=&quot;background:lightsteelblue&quot;<br /> |[[Image:Tetralogy of Fallot.jpg|100px]]<br /> |'''Tetralogy of Fallot'''<br /> |9-14% of CHD<br /> |Classic group of defects: pulmonary stenosis, VSD, dextroposition of aorta, RV hypertrophy. Results in cyanosis.<br /> |-<br /> |[[Image:Transposition of the Great Vessels.jpg|100px]]<br /> |'''Transposition of the Great Vessels'''<br /> |10-11% of CHD<br /> |Aorta arises from the RV with the pulmonary trunk arising from the left. Most common cause of cyanotic heart disease in newborns; surgically corrected.<br /> |-style=&quot;background:lightsteelblue&quot;<br /> |[[Image:Atrial Septal Defect.jpg|100px]]<br /> |'''Atrial Septal Defect'''<br /> |6-10% of CHD; more common in females<br /> |Most commonly patent foramen ovale; can also be an ostium secundum defect, an endocardial cushion defect with ostium primum defect, sinus venosus defect, common atrium. Results in cyanosis due to right-to-left shunt.<br /> |-<br /> |[[Image:Pulmonary Atresia.jpg|100px]][[Image:Pulmonary Stenosis.jpg|100px]]<br /> |'''Pulmonary Atresia &amp; Pulmonary Stenosis'''<br /> |10% of CHD<br /> |Unequal division of trunks causes cusps to fuse to form a dome with a narrow/non-existent lumen. Heart-lung transplantation may be the only therapy.<br /> |-style=&quot;background:lightsteelblue&quot;<br /> |[[Image:Patent Ductus Arteriosus.jpg|100px]]<br /> |'''Patent Ductus Arteriosus'''<br /> |6-8% of CHD; 2-3 times more common in females; common in preterm newborns<br /> |Failure of contraction of the muscular wall of the DA. Spontaneous or surgical closure.<br /> |-<br /> |[[Image:Aortic Stenosis.jpg|100px]]<br /> |'''Aortic Stenosis'''<br /> |7% of CHD<br /> |Persistence of tissue that normally degenerates. Results in LV hypertrophy, heart murmurs.<br /> |-style=&quot;background:lightsteelblue&quot;<br /> |[[Image:Hypoplastic Left Heart.jpg|100px]][[Image:Functional Hypoplastic Left Heart.jpg|100px]]<br /> |'''Hypoplastic Left Heart Syndrome'''<br /> |4-8% of CHD<br /> |RV maintains both pulmonary and systemic circulations aided by an ASD. Infants usually die within weeks.<br /> |-<br /> |[[Image:Coarctation of the Aorta.jpg|100px]]<br /> |'''Coarctation of the Aorta'''<br /> |5-7% of CHD<br /> |Aortic constriction. Treatment aims at maintaining the ductus arteriosus via prostaglandins.<br /> |-style=&quot;background:lightsteelblue&quot;<br /> |[[Image:Partial Anomalous Pulmonary Venous Drainage.jpg|100px]][[Image:Total Anomalous Pulmonary Venous Connection.jpg|100px]]<br /> |'''Partial/Total Anomalous Pulmonary Venous Connection'''<br /> |&lt;4% of CHD; more common in females<br /> |Total or partial lack of connection of the pulmonary veins with LA. They open into RA, one of the systemic veins or both. The overloaded pulmonary circuit leads to cyanosis, tachypnoea and dyspnoea. Treatment is via surgical redirection<br /> |-<br /> |[[Image:Tricuspid Atresia.jpg|100px]]<br /> |'''Tricuspid Atresia'''<br /> |1-3% of CHD<br /> |Complete lack of formation of the tricuspid valve with absence of direct connection between the right atrium and right ventricle. Results in cyanosis.<br /> |-style=&quot;background:lightsteelblue&quot;<br /> |[[Image:Double Outlet Right Ventricle.jpg|100px]]<br /> |'''Double Outlet Right Ventricle'''<br /> |1-1.5% of CHD<br /> |Both large arteries arise wholly or mainly from the right ventricle. Arrangement of the atrioventricular valves and the ventriculoarterial connections are variable. Clinical manifestations variable.<br /> |-<br /> |[[Image:Interrupted Aortic Arch.jpg|100px]]<br /> |'''Interrupted Aortic Arch'''<br /> |Very rare<br /> |Gap in ascending and descending thoracic aorta. Treated with prostaglandin to maintain ductus arteriosus followed by surgery.<br /> |}<br /> <br /> {| width=&quot;100%&quot;<br /> |-<br /> |width=&quot;30%&quot; bgcolor=&quot;gold&quot;|&lt;big&gt;'''[[Intermediate_-_Heart_Valves|Back to Valve Development]]'''&lt;/big&gt;<br /> |<br /> |width=&quot;30%&quot; bgcolor=&quot;gold&quot; align=&quot;right&quot;|&lt;big&gt;'''[[Intermediate_-_Vascular_Overview|Next: Vascular Development]]'''&lt;/big&gt;<br /> |-<br /> |<br /> |<br /> |bgcolor=&quot;#FF6666&quot; align=&quot;right&quot;|&lt;big&gt;'''[[Advanced_-_Abnormalities|Go to this section in the advanced level]]'''&lt;/big&gt;<br /> |}<br /> <br /> {{Template:Glossary}}<br /> <br /> '''Atresia:''' Abnormal closure or absence of a body vessel or orifice.<br /> <br /> '''Congenital heart disease:''' Abnormal structure or function of the heart due to a developmental defect arising prior to birth.<br /> <br /> '''Cyanosis:''' Blue colouration of the skin and mucous membrane due to poor oxygenation of the blood.<br /> <br /> '''Dyspnoea:''' Shortness of breath.<br /> <br /> '''Heart murmur:''' Extra heart sounds appearing upon auscultation due to turbulent blood flow.<br /> <br /> '''Hypertrophy:''' Increase in size of an organ or tissue due to enlargement of component cells.<br /> <br /> '''Pulmonary circulation:''' Carries blood between the heart and lungs.<br /> <br /> '''Stenosis:''' Abnormal narrowing of a blood vessel or orifice.<br /> <br /> '''Systemic circulation:''' Carries oxygenated blood away from the heart to the other body organs and returns to the heart deoxygenated.<br /> <br /> '''Tachypnoea:''' Abnormally rapid breathing rate.<br /> <br /> [[category:heart]]</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=File:Ventricular_Septal_Defect.jpg&diff=17006 2010-03-14T01:28:17Z

<p>Z3212774: category:Heart ILP</p> <hr /> <div>[[category:Heart ILP]]</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=File:Tricuspid_Atresia.jpg&diff=17005 2010-03-14T01:27:55Z

<p>Z3212774: category:Heart ILP</p> <hr /> <div>[[category:Heart ILP]]</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=File:Transposition_of_the_Great_Vessels.jpg&diff=17004 2010-03-14T01:27:30Z

<p>Z3212774: category:Heart ILP</p> <hr /> <div>[[category:Heart ILP]]</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=File:Tetralogy_of_Fallot.jpg&diff=17003 2010-03-14T01:27:09Z

<p>Z3212774: category:Heart ILP</p> <hr /> <div>[[category:Heart ILP]]</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=File:Total_Anomalous_Pulmonary_Venous_Connection.jpg&diff=17002 2010-03-14T01:26:45Z

<p>Z3212774: category:Heart ILP</p> <hr /> <div>[[category:Heart ILP]]</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=File:Pulmonary_Stenosis.jpg&diff=17001 2010-03-14T01:26:17Z

<p>Z3212774: category:Heart ILP</p> <hr /> <div>[[category:Heart ILP]]</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=File:Pulmonary_Atresia.jpg&diff=17000 2010-03-14T01:25:54Z

<p>Z3212774: category:Heart ILP</p> <hr /> <div>[[category:Heart ILP]]</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=File:Patent_Ductus_Arteriosus.jpg&diff=16999 2010-03-14T01:25:36Z

<p>Z3212774: category:Heart ILP</p> <hr /> <div>[[category:Heart ILP]]</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=File:Partial_Anomalous_Pulmonary_Venous_Drainage.jpg&diff=16998 2010-03-14T01:25:16Z

<p>Z3212774: category:Heart ILP</p> <hr /> <div>[[category:Heart ILP]]</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=File:Interrupted_Aortic_Arch.jpg&diff=16997 2010-03-14T01:24:47Z

<p>Z3212774: category:Heart ILP</p> <hr /> <div>[[category:Heart ILP]]</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=File:Hypoplastic_Left_Heart.jpg&diff=16996 2010-03-14T01:24:20Z

<p>Z3212774: category:Heart ILP</p> <hr /> <div>[[category:Heart ILP]]</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=File:Functional_Hypoplastic_Left_Heart.jpg&diff=16995 2010-03-14T01:24:00Z

<p>Z3212774: category:Heart ILP</p> <hr /> <div>[[category:Heart ILP]]</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=File:Double_Outlet_Right_Ventricle.jpg&diff=16994 2010-03-14T01:23:34Z

<p>Z3212774: category:Heart ILP</p> <hr /> <div>[[category:Heart ILP]]</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=File:Coarctation_of_the_Aorta.jpg&diff=16993 2010-03-14T01:23:04Z

<p>Z3212774: category:Heart ILP</p> <hr /> <div>[[category:Heart ILP]]</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=File:Atrial_Septal_Defect.jpg&diff=16992 2010-03-14T01:22:44Z

<p>Z3212774: category:Heart ILP</p> <hr /> <div>[[category:Heart ILP]]</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=File:Aortic_Stenosis.jpg&diff=16991 2010-03-14T01:22:23Z

<p>Z3212774: category:Heart ILP</p> <hr /> <div>[[category:Heart ILP]]</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=Intermediate_-_Heart_Valves&diff=16990 2010-03-14T01:19:32Z

<p>Z3212774: </p> <hr /> <div>[[Image:Intermediateicon.jpg|left|70px|link=Intermediate_Cardiac_Embryology]]<br /> {{Template:Intermediate Cardiac menu}}<br /> <br /> <br /> {{Template:Cardiac_modules}}<br /> <br /> [[Image:Intermediate Heart Development Timeline.jpg|center|850px]]<br /> <br /> <br /> There are four valves in the adult heart, depicted below. There are ''two'' AV valves which comprise leaflets as well as the structures that tether these leaflets to the ventricular walls. The '''aortic''' and '''pulmonary''' valves, termed the '''semilunar valves''', are located in the aorta and pulmonary trunk respectively. They are each made of ''three'' cusps.<br /> <br /> [[Image:Adult Heart Valves.jpg|thumb|center|upright=2.5|Adult Heart Valves]]<br /> <br /> {|style=&quot;float:left&quot;<br /> |-<br /> |[[Image:AV Canal Division (Superior View).jpg|thumb|upright=2|Division of the AV canal]]<br /> |-<br /> |[[Image:AV Valves.jpg|thumb|center|upright=2|Development of the mitral and tricuspid valves]]<br /> |}<br /> {|style=&quot;float:right&quot;<br /> |-<br /> |[[Image:Semilunar Valves.jpg|thumb|center|upright=2|Development of the semilunar valves]]<br /> |-<br /> |[[Image:Semilunar Cusps.jpg|thumb|upright=2|Development of the semilunar cusps]]<br /> |}<br /> <br /> <br /> The AV valves begin to form between the fifth and eighth weeks of development. The left AV valve has ''anterior'' and ''posterior'' leaflets and is termed the '''bicuspid''' or '''mitral''' valve. The right AV valve has a third, small, ''septal'' cusp and thus is called the '''tricuspid''' valve. The '''valve leaflets''' are attached to the ventricular walls by thin fibrous chords: the '''chordae tendineae''', which insert into small muscles attached to the ventricle wall: the '''papillary muscles'''. These structures are sculpted from the ventricular wall (see left).<br /> <br /> <br /> The semilunar valves are formed from the '''bulbar ridges''' and subendocardial valve tissue. The primordial semilunar valve consists of a mesenchymal core covered by endocardium. Excavation occurs, thinning the valve tissue thus creating its final shape (see right).<br /> <br /> {| width=&quot;100%&quot;<br /> |-<br /> |width=&quot;30%&quot; bgcolor=&quot;gold&quot;|&lt;big&gt;'''[[Intermediate_-_Outflow_Tract|Back to Outflow Tract Division]]'''&lt;/big&gt;<br /> |<br /> |width=&quot;30%&quot; bgcolor=&quot;gold&quot; align=&quot;right&quot;|&lt;big&gt;'''[[Intermediate_-_Cardiac_Abnormalities|Next: Developmental Abnormalities]]'''&lt;/big&gt;<br /> |-<br /> |<br /> |<br /> |bgcolor=&quot;#FF6666&quot; align=&quot;right&quot;|&lt;big&gt;'''[[Advanced_-_Valve_Development|Go to this section in the advanced level]]'''&lt;/big&gt;<br /> |}<br /> <br /> {{Template:Glossary}}<br /> <br /> '''Aortic valve:''' Three-leaflet valve located at the junction between the left ventricle and aortic entrance.<br /> <br /> '''Bulbar ridges:''' Endocardial cushion tissue located in the bulbus cordis extending into the truncus arteriosus thus forming ridges. These fuse together to form the aorticopulmonary septum.<br /> <br /> '''Chordae tendineae:''' Cord-like tendons connecting the papillary muscles to the leaflets of the mitral and tricuspid valves.<br /> <br /> '''Mitral valve:''' (Bicuspid valve) two leaflet valve located on the left side of the heart i.e. between the left atrium and ventricle.<br /> <br /> '''Papillary muscles:''' Small muscles found on the inner myocardium of the left and right ventricles. They are attached to the mitral and tricuspid valves via the chordae tendineae and serve to limit the movements of the valves.<br /> <br /> '''Pulmonary valve:''' Three-leaflet valve located at the junction between the right ventricle and the pulmonary trunk.<br /> <br /> '''Semilunar valves:''' Flaps of endocardium and connective tissue reinforced by fibres which prevent the valves from turning inside out. They are shaped like a half moon, hence the name semilunar. The semilunar valves are located between the aorta and the left ventricle and between the pulmonary artery and the right ventricle.<br /> <br /> '''Trabeculae (trabeculations):''' Muscular beams located within the ventricles and parts of the atria of the heart.<br /> <br /> '''Tricuspid valve:''' Three leaflet valve located in the right atrioventricular canal i.e. between the right atrium and ventricle.<br /> <br /> [[category:heart]]</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=File:Semilunar_Cusps.jpg&diff=16989 2010-03-14T01:17:12Z

<p>Z3212774: category:Heart ILP Longitudinal sections of the aorta showing development of the semilunar cusps forming the aortic valve.</p> <hr /> <div>[[category:Heart ILP]]<br /> <br /> Longitudinal sections of the aorta showing development of the semilunar cusps forming the aortic valve.</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=File:Semilunar_Valves.jpg&diff=16988 2010-03-14T01:16:20Z

<p>Z3212774: category:Heart ILP Development of the semilunar valves of the aorta and pulmonary trunk as shown through a transverse section of the bulbus cordis. The walls and valves of the aorta and pulmonary trunk form followed by rotation of the vessels which e</p> <hr /> <div>[[category:Heart ILP]]<br /> <br /> Development of the semilunar valves of the aorta and pulmonary trunk as shown through a transverse section of the bulbus cordis. The walls and valves of the aorta and pulmonary trunk form followed by rotation of the vessels which establishes the adult relations of the valves.</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=File:AV_Valves.jpg&diff=16987 2010-03-14T01:15:25Z

<p>Z3212774: category:Heart ILP Sequence of events in the development of the atrioventricular valves. The structures of the valves i.e. the papillary muscles, chordae tendineae and cusps are sculpted from the muscular ventricular walls.</p> <hr /> <div>[[category:Heart ILP]]<br /> <br /> Sequence of events in the development of the atrioventricular valves. The structures of the valves i.e. the papillary muscles, chordae tendineae and cusps are sculpted from the muscular ventricular walls.</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=File:AV_Canal_Division_(Superior_View).jpg&diff=16986 2010-03-14T01:14:38Z

<p>Z3212774: category:Heart ILP Development of the atrioventricular septum over weeks four and five. The right and left atrioventricular canals are remodelled to later become the atrioventricular (tricuspid and mitral) valves.</p> <hr /> <div>[[category:Heart ILP]]<br /> <br /> Development of the atrioventricular septum over weeks four and five. The right and left atrioventricular canals are remodelled to later become the atrioventricular (tricuspid and mitral) valves.</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=File:Adult_Heart_Valves.jpg&diff=16985 2010-03-14T01:13:45Z

<p>Z3212774: category:Heart ILP Adult heart showing aortic, pulmonary, mitral and tricuspid valves.</p> <hr /> <div>[[category:Heart ILP]]<br /> <br /> Adult heart showing aortic, pulmonary, mitral and tricuspid valves.</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=Intermediate_-_Outflow_Tract&diff=16984 2010-03-14T01:03:06Z

<p>Z3212774: </p> <hr /> <div>[[Image:Intermediateicon.jpg|left|70px|link=Intermediate_Cardiac_Embryology]]<br /> {{Template:Intermediate Cardiac menu}}<br /> <br /> <br /> {{Template:Cardiac_modules}}<br /> <br /> [[Image:Intermediate Heart Development Timeline.jpg|center|850px]]<br /> <br /> <br /> Active proliferation of '''neural crest mesenchymal cells''' in the '''bulbus cordis''' during the fifth week creates '''bulbar ridges''' which are continuous in the '''truncus arteriosus'''. The neural crest cells migrate through the primordial '''pharynx''' and over the '''aortic arch arteries''' to reach the '''outflow tract''' (pictured below). The bulbar ridges undergo a 180° spiral to create the helical '''aorticopulmonary septum'''. As the ridges grow and develop myocardium they fuse in a distal-to-proximal direction. Fusion occurs during the sixth week, allowing for cleavage of the '''aorta''' and '''pulmonary trunk'''. The spiralling nature of the ridges causes the pulmonary trunk to twist around the aorta. Note that the bulbus cordis accounts for the smooth '''conus arteriosus''' (or '''infundibulum''') in the right ventricle and the '''aortic vestibule''' in the left ventricle.<br /> <br /> {|align=center<br /> |-<br /> |[[Image:Cardiac Neural Crest Migration.jpg|thumb|left|upright=2|Migration of the cardiac neural crest]]<br /> |[[Image:Outflow Tract Division (Cross-Section).jpg|thumb|right|upright=2|Cross-sections of the outflow tract illustrating the truncal and bulbar ridges]]<br /> |}<br /> <br /> The following animation shows the process occuring in a right oblique view of the heart with the anterolateral wall of the right ventricle having been removed.<br /> <br /> <br /> &lt;Flowplayer height=&quot;564&quot; width=&quot;720&quot; autoplay=&quot;false&quot;&gt;Heart outflow tract 002.flv&lt;/Flowplayer&gt;<br /> <br /> <br /> {| width=&quot;100%&quot;<br /> |-<br /> |width=&quot;30%&quot; bgcolor=&quot;gold&quot;|&lt;big&gt;'''[[Intermediate_-_Atrial_Ventricular_Septation|Back to Septation]]'''&lt;/big&gt;<br /> |<br /> |width=&quot;30%&quot; bgcolor=&quot;gold&quot; align=&quot;right&quot;|&lt;big&gt;'''[[Intermediate_-_Heart_Valves|Next: Development of Heart Valves]]'''&lt;/big&gt;<br /> |-<br /> |bgcolor=&quot;limegreen&quot;|&lt;big&gt;'''[[Basic_-_Embryonic_Heart_Divisions|Go to this section in the basic level]]'''&lt;/big&gt;<br /> |<br /> |bgcolor=&quot;#FF6666&quot; align=&quot;right&quot;|&lt;big&gt;'''[[Advanced_-_Outflow_Tract|Go to this section in the advanced level]]'''&lt;/big&gt;<br /> |}<br /> <br /> {{Template:Glossary}}<br /> <br /> '''Aorta:''' The largest artery in the human body originating in the left ventricle. The aorta ascends, arches over the heart and then descends through the abdomen.<br /> <br /> '''Aortic arch arteries:''' (Or pharyngeal arch arteries.) Each early developing pharyngeal arch contains a lateral pair of arteries arising from the aortic sac, above the heart, and running into the dorsal aorta. Later in development these arch arteries are extensively remodelled to form specific components of the vascular system.<br /> <br /> '''Aortic vestibule:''' Smooth-walled portion of the left ventricle directly below the aortic valve.<br /> <br /> '''Aorticopulmonary septum:''' Division between the aorta and the pulmonary trunk formed from the bulbar ridges.<br /> <br /> '''Bulbus cordis:''' A region of the early developing heart tube forming the common outflow tract, will differentiate to form three regions of the heart. <br /> <br /> '''Conus arteriosus:''' An embryological heart outflow structure, that forms in early cardiac development and will later divides into the pulmonary artery and aorta. Term is also used clinically to describe the malformation of the cardiac outflow pattern, where only one artery arises from the heart and forms the aorta and pulmonary artery.<br /> <br /> '''Infundibulum:''' Smooth-walled portion of the right ventricle directly below the pulmonary valve.<br /> <br /> '''Neural crest mesenchyme:''' Connective tissue arising from critical cells in the cranial region of the embryo. These paired dorsal lateral streaks of cells migrate throughout the embryo and can differentiate into many different cell types (= pluripotential). Those that remain on the dorsal neural tube form the sensory spinal ganglia (DRG), those that migrate ventrally form the sympatheitic ganglia. Neural crest cells also migrate into the somites and regions throught the entire embryo.<br /> <br /> '''Outflow tract:''' Exit of blood from the heart tube formed by the truncus arteriosus.<br /> <br /> '''Pharynx:''' (Or throat) Forms the initial segment of the upper respiratory tract divided anatomically into three regions: nasopharynx, oropharynx, and laryngopharynx (hypopharynx). Anatomically extends from the base of the skull to the level of the sixth cervical vertebra.<br /> <br /> '''Pulmonary trunk:''' A vessel that arises from the right ventricle of the heart, extends upward, and divides into the right and left pulmonary arteries that transport deoxygenated blood to the lungs.<br /> <br /> '''Truncus arteriosus:''' An embryological heart outflow structure, that forms in early cardiac development and will later divides into the pulmonary artery and aorta. Term is also used clinically to describe the malformation of the cardiac outflow pattern, where only one artery arises from the heart and forms the aorta and pulmonary artery.<br /> <br /> [[category:heart]]</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=File:Outflow_Tract_Division_(Cross-Section).jpg&diff=16983 2010-03-14T01:02:08Z

<p>Z3212774: category:Heart ILP Cross sections of the outflow tract before and after fusion of the conotruncal ridges.</p> <hr /> <div>[[category:Heart ILP]]<br /> <br /> Cross sections of the outflow tract before and after fusion of the conotruncal ridges.</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=File:Cardiac_Neural_Crest_Migration.jpg&diff=16982 2010-03-14T01:00:35Z

<p>Z3212774: category:Heart ILP In order to complete division of the outflow tract, mesenchyme derived from the cardiac neural crest migrates over the aortic arch arteries to invade the conotruncus.</p> <hr /> <div>[[category:Heart ILP]]<br /> <br /> In order to complete division of the outflow tract, mesenchyme derived from the cardiac neural crest migrates over the aortic arch arteries to invade the conotruncus.</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=Intermediate_-_Atrial_Ventricular_Septation&diff=16978 2010-03-14T00:57:10Z

<p>Z3212774: </p> <hr /> <div>[[Image:Intermediateicon.jpg|left|70px|link=Intermediate_Cardiac_Embryology]]<br /> {{Template:Intermediate Cardiac menu}}<br /> <br /> <br /> {{Template:Cardiac_modules}}<br /> <br /> [[Image:Intermediate Heart Development Timeline.jpg|center|850px]]<br /> <br /> <br /> All of the partitioning of the primitive heart occurs between the middle of the fourth week and the end of the fifth week. The following animation shows the processes involved in the division of the '''atrioventricular canal''', atria and ventricles. These are described in more detail in the text below.<br /> <br /> <br /> &lt;Flowplayer height=&quot;564&quot; width=&quot;720&quot; autoplay=&quot;false&quot;&gt;Heart septation 003.flv&lt;/Flowplayer&gt;<br /> <br /> <br /> ==Division of the Atrioventricular (AV) Canal==<br /> <br /> Two '''endocardial cushions''' form on the dorsal and ventral surfaces of the AV canal, referred to as the superior and inferior cushions respectively. The cardiac jelly in this region expands while mesenchymal cells from the endocardium invade the cushions, allowing them to grow and fuse. This fusion divides the common AV canal into the right and left canals, hence partially separating the primitive atrium and ventricle. Two smaller endocardial cushions also form on the lateral walls of the AV canal, which later help to form the '''mitral''' and '''tricuspid''' heart valves.<br /> <br /> ==Septation of the Atria==<br /> <br /> Membranous tissue forming the '''septum primum''' grows from the roof of the atrium, dividing it into left and right halves. The space between the septum primum and the endocardial cushions is referred to as the '''foramen primum'''. Apoptosis-induced perforations appear in the centre of the septum primum to produce the '''foramen secundum'''. At this time the strong, muscular '''septum secundum''' grows immediately to the right of the septum primum and gradually overlaps the foramen secundum during the fifth and sixth weeks of development. The incomplete partition of the atrium by the septum secundum forms the '''foramen ovale'''.<br /> <br /> Blood flows from the '''right atrium''' through the foramen ovale and foramen secundum to the '''left atrium''', forming a right-to-left shunt. The remaining portion of the septum primum acts as the valve of the foramen ovale. Blood cannot flow in the opposite direction, as the muscular strength of the septum secundum prevents prolapse of the septum primum.<br /> <br /> The flow of blood throughout the septated atria can be seen below:<br /> <br /> [[Image:Embryonic Heart Blood Flow.jpg|thumb|center|upright=2|Blood flow through the atria]]<br /> <br /> ===Remodelling of the Inflow tract and Atria===<br /> The development of two left-to-right shunts in the venous system leads to an increase in size of the right horn of the sinus venosus and consequently a decrease in left horn by the end of the fourth week. The '''sinuatrial orifice''' correspondingly shifts to the right and thus becomes located in the right atrium. Hence the right atrium receives the '''superior vena cava''' and '''inferior vena cava''' in the adult. The left sinus horn regresses to form the '''coronary sinus''' in humans. Thus the sinus venosus gradually becomes incorporated into the right atrium. It contributes to the smooth-walled part of the adult right atrium, referred to as the '''sinus venarum'''. The trabeculated right atrium corresponds to the primordial atrium; the division between these structures is indicated by the inner '''crista terminalis''' and outer '''sulcus terminalis'''.<br /> <br /> The primordial pulmonary vein develops in the dorsal wall of the LA. As the atrium increases in size it incorporates more of the branches of the pulmonary vein, culminating in its receiving the four '''pulmonary veins'''. The smooth wall of the adult LA originated from the primordial pulmonary vein while the trabeculated wall represents the primordial atrium.<br /> <br /> ==Septation of the Ventricles==<br /> <br /> Minor '''trabeculations''' appear during early development of the primordial ventricle. Following growth of the ventricles further trabeculations appear and grow as larger, muscular structures. Some researchers believe that as the trabeculations grow they coalesce resulting in the formation of the ventricular septum. However, the more commonly described theory of septation begins with the appearance of a primordial muscular interventricular (IV) ridge developing in the floor of the ventricle near the '''apex'''. As either side of the ventricle grows and dilates, their medial walls fuse forming the prominent '''IV septum'''. The foramen located between the cranial portion of the IV septum and the endocardial cushions: the '''IV foramen''', closes by the end of the seventh week as the '''bulbar ridges''' (see next section) fuse with the endocardial cushions.<br /> <br /> <br /> {| width=&quot;100%&quot;<br /> |-<br /> |width=&quot;30%&quot; bgcolor=&quot;gold&quot;|&lt;big&gt;'''[[Intermediate_-_Heart_Tube_Looping|Back to Looping]]'''&lt;/big&gt;<br /> |<br /> |width=&quot;30%&quot; bgcolor=&quot;gold&quot; align=&quot;right&quot;|&lt;big&gt;'''[[Intermediate_-_Outflow_Tract|Next: Division of the Outflow Tract]]'''&lt;/big&gt;<br /> |-<br /> |bgcolor=&quot;limegreen&quot;|&lt;big&gt;'''[[Basic_-_Embryonic_Heart_Divisions|Go to this section in the basic level]]'''&lt;/big&gt;<br /> |<br /> |bgcolor=&quot;#FF6666&quot; align=&quot;right&quot;|&lt;big&gt;'''[[Advanced_-_Cardiac_Septation|Go to this section in the advanced level]]'''&lt;/big&gt;<br /> |}<br /> <br /> {{Template:Glossary}}<br /> <br /> '''Apex:''' Anatomical term referring to the most inferior, left, downwards pointing part of the heart.<br /> <br /> '''Atrioventricular canal:''' Junction between the primitive atrium and primitive ventricle in the embryo. This canal splits to later form two atrioventricular canals which consequently form the valves of the adult heart.<br /> <br /> '''Bulbar ridges:''' Endocardial cushion tissue located in the bulbus cordis extending into the truncus arteriosus thus forming ridges. These fuse together to form the aorticopulmonary septum.<br /> <br /> '''Coronary sinus:''' a venous sinus emptying into the right atrium that collects blood from the myocardium of the heart.<br /> <br /> '''Endocardial cushions:''' Swellings of migrated cells on the inner lining of the heart located in the atrioventricular canal.<br /> <br /> '''Foramen ovale:''' Shunt allowing blood to enter the left atrium from the right atrium. It is located in the septum secundum.<br /> <br /> '''Foramen primum:''' Original space between the septum primum and the fused endocardial cushions as the septum primum grows towards the cushions.<br /> <br /> '''Foramen secundum:''' Refers to the coalesced perforations in the septum primum after it has fused with the endocardial cushions.<br /> <br /> '''Inferior vena cava (IVC):''' Large vein which carries deoxygenated blood from the lower half of the body to the right atrium.<br /> <br /> '''Interventricular septum:''' Wall of muscular tissue growing from the base of the heart dividing the primitive ventricle into the left and right ventricles.<br /> <br /> '''Interventricular foramen:''' Space between the interventricular septum and the fused endocardial cushions. The foramen closes when the septum fuses with the endocardial cushions and bulbar ridges.<br /> <br /> '''Mitral valve (bicuspid valve):''' Two leaflet valve located on the left side of the heart i.e. between the left atrium and ventricle.<br /> <br /> '''Pulmonary veins:''' Four veins that allow oxygenated blood from the lungs to empty into the left atrium.<br /> <br /> '''Septum primum:''' Original structure growing from the roof of the heart towards the endocardial cushions dividing the primitive atrium.<br /> <br /> '''Septum secundum:''' Second structure growing to the right of the septum primum dividing the primitive atrium.<br /> <br /> '''Sinuatrial orifice:''' The opening between the sinus venosus and right atrium which has two valve leaflets to prevent backflow of blood.<br /> <br /> '''Sinus venarum:''' Smooth-walled portion of the adult right atrium; originally the left horn of the sinus venosus.<br /> <br /> '''Superior vena cava (SVC):''' Short vein which carries deoxygenated blood from the upper half of the body to the right atrium.<br /> <br /> '''Trabeculae (trabeculations):''' Muscular beams located within the ventricles and parts of the atria of the heart.<br /> <br /> '''Tricuspid valve:''' Three leaflet valve located in the right atrioventricular canal i.e. between the right atrium and ventricle.<br /> <br /> [[category:heart]]</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=File:Embryonic_Heart_Blood_Flow.jpg&diff=16977 2010-03-14T00:56:22Z

<p>Z3212774: category:Heart ILP Oxygenated (from the placenta) and non-oxygenated (from the lower body) blood enters the right atrium via the sinus venosus. Part of this blood travels to the right ventricle and then through the pulmonary circulation. The rest of </p> <hr /> <div>[[category:Heart ILP]]<br /> <br /> Oxygenated (from the placenta) and non-oxygenated (from the lower body) blood enters the right atrium via the sinus venosus. Part of this blood travels to the right ventricle and then through the pulmonary circulation. The rest of the blood in the right atrium passes through the foramen ovale to the left atrium. The septum primum acts as a valve of the foramen ovale preventing backflow of blood (i.e. from the left atrium to right atrium). Blood returning from the pulmonary circulation and blood from the right atrium flows from the left atrium into the left ventricle. Blood from the left ventricle exits the heart via the aorta.</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=Intermediate_-_Heart_Tube_Looping&diff=16976 2010-03-14T00:52:11Z

<p>Z3212774: </p> <hr /> <div>[[Image:Intermediateicon.jpg|left|70px|link=Intermediate_Cardiac_Embryology]]<br /> {{Template:Intermediate Cardiac menu}}<br /> <br /> <br /> {{Template:Cardiac_modules}}<br /> <br /> [[Image:Intermediate Heart Development Timeline.jpg|center|850px]]<br /> <br /> <br /> Looping of the heart tube allows the straight heart tube to form a more complex structure reminiscent of the adult heart. Most cardiac looping occurs during the fourth week and completes during the fifth week of development. The steps in looping can be summarised as:<br /> #The straight heart tube begins to elongate with simultaneous growth in the '''bulbus cordis''' and '''primitive ventricle'''.<br /> #This forces the heart to bend ventrally and rotate to the right, forming a C-shaped loop with convex side situated on the right.<br /> #The ventricular bend moves caudally and the distance between the outflow and inflow tracts diminishes.<br /> #The atrial and outflow poles converge and myocardial cells are added, forming the '''truncus arteriosus'''.<br /> Hence an S-shape is formed with the first bend of the 'S' being the large ventricular bend while the bend at the junction of the atrium and sinus venosus forms the second 'S' bend.<br /> <br /> The following animation portrays these concepts from the traditional, ventral view of the heart. You can also view this animation from a lateral [[Intermediate_-_Heart_Tube_Looping_2|left]] or [[Intermediate_-_Heart_Tube_Looping_3|right]] view.<br /> <br /> <br /> &lt;Flowplayer height=&quot;564&quot; width=&quot;720&quot; autoplay=&quot;false&quot;&gt;Heart looping 002.flv&lt;/Flowplayer&gt;<br /> <br /> <br /> Throughout the morphological changes of the heart tube during looping, the locations of the divisions of the heart tube change, as described above.<br /> <br /> [[Image:Heart Looping Sequence.jpg|thumb|center|upright=3.5|Movement of the parts of the heart tube during looping]]<br /> <br /> The following scanning electron micrographs illustrate the same morphological changes in the heart tube described above. The straight heart tube can be seen to form a C-shape, with the convex bulge on the right side of the embryo representing much of the expansive conotruncus and right ventricle. By day 25 it is possible to see the early formation of the S-shaped loop where the left-sided predominant bulge indicates the left ventricle and the atrium and sinus venosus have moved dorsally.<br /> <br /> [[Image:Heart Looping Sequence (SEMs).jpg|thumb|center|upright=4.5|Series of scanning EMs showing the rapid change in the appearance of the heart tube]]<br /> <br /> Note that previously the heart was attached to the dorsal '''pericardial wall''' by the '''dorsal mesocardium'''. During heart looping, the dorsal mesocardium degenerates, forming the '''transverse pericardial sinus''' (a point of communication across the pericardial coelom).<br /> <br /> <br /> {| width=&quot;100%&quot;<br /> |-<br /> |width=&quot;30%&quot; bgcolor=&quot;gold&quot;|&lt;big&gt;'''[[Intermediate_-_Primordial_Heart_Tube|Back to the Primordial Heart Tube]]'''&lt;/big&gt;<br /> |<br /> |width=&quot;30%&quot; bgcolor=&quot;gold&quot; align=&quot;right&quot;|&lt;big&gt;'''[[Intermediate_-_Atrial_Ventricular_Septation|Next: Heart Septation]]'''&lt;/big&gt;<br /> |-<br /> |bgcolor=&quot;limegreen&quot;|&lt;big&gt;'''[[Basic_-_Embryonic_Heart_Divisions|Go to this section in the basic level]]'''&lt;/big&gt;<br /> |<br /> |bgcolor=&quot;#FF6666&quot; align=&quot;right&quot;|&lt;big&gt;'''[[Advanced_-_Cardiac_Looping|Go to this section in the advanced level]]'''&lt;/big&gt;<br /> |}<br /> <br /> {{Template:Glossary}}<br /> <br /> '''Bulbus cordis:''' A region of the early developing heart tube forming the common outflow tract, will differentiate to form three regions of the heart. <br /> <br /> '''Dorsal mesocardium:''' The mesentery attaching the heart to the dorsal wall of the pericardial coelom. This breaks down to form a space known as the transverse pericardial sinus.<br /> <br /> '''Inflow tract:''' Entrance of blood into the heart tube; the sinus venosus portion of the tube.<br /> <br /> '''Outflow tract:''' Exit of blood from the heart tube formed by the truncus arteriosus.<br /> <br /> '''Primordial atrium:''' Common cavity in the upper portion of the developing heart. Later divides to form the left and right atria.<br /> <br /> '''Primordial ventricle:''' Common cavity in the lower portion of the developing heart. Later divides to form the left and right ventricles.<br /> <br /> '''Sinus venosus:''' An early developmental cardiovascular structure, thin walled cavity, forming the input to developing heart which has 3 venous inputs (vitelline vein, umbilical vein, common cardinal vein). Later in heart development this structure gets incorporated into the wall of the future right atrium.<br /> <br /> '''Transverse pericardial sinus:''' Dorsal area within the pericardial coelom, initially occupied by the dorsal mesocardium.<br /> <br /> '''Truncus arteriosus:''' An embryological heart outflow structure, that forms in early cardiac development and will later divides into the pulmonary artery and aorta. Term is also used clinically to describe the malformation of the cardiac outflow pattern, where only one artery arises from the heart and forms the aorta and pulmonary artery.<br /> <br /> [[category:heart]]</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=File:Heart_Looping_Sequence_(SEMs).jpg&diff=16975 2010-03-14T00:50:59Z

<p>Z3212774: category:Heart ILP {{Template:SEM}} The heart tube loops initially to form a C-shape and as looping progresses the heart begins to resemble an S-shape (or U-shape ventrally).</p> <hr /> <div>[[category:Heart ILP]]<br /> <br /> {{Template:SEM}}<br /> <br /> The heart tube loops initially to form a C-shape and as looping progresses the heart begins to resemble an S-shape (or U-shape ventrally).</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=File:Heart_Looping_Sequence.jpg&diff=16974 2010-03-14T00:49:50Z

<p>Z3212774: category:Heart ILP Shows the sequence of events in heart looping. The heart begins as a straight tube then bends ventrally. Rotation brings the bulge of the ventral bend (predominantly the bulbus cordis and ventricle) to the right, forming a C-shaped</p> <hr /> <div>[[category:Heart ILP]]<br /> <br /> Shows the sequence of events in heart looping. The heart begins as a straight tube then bends ventrally. Rotation brings the bulge of the ventral bend (predominantly the bulbus cordis and ventricle) to the right, forming a C-shaped loop. As the atrium is brought cranially, the poles of the heart converge. The heart now appears as an S-shape, with the first bend in the S between the bulbus cordis and ventricle and the second bend between the atrium and sinus venosus. The bulbus cordis and arterial trunk move ventral to the atrium to form the later outflow tract. The atrium now lies superior to the ventricle.</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=Intermediate_-_Primordial_Heart_Tube&diff=16970 2010-03-14T00:45:53Z

<p>Z3212774: </p> <hr /> <div>[[Image:Intermediateicon.jpg|left|70px|link=Intermediate_Cardiac_Embryology]]<br /> {{Template:Intermediate Cardiac menu}}<br /> <br /> <br /> {{Template:Cardiac_modules}}<br /> <br /> [[Image:Intermediate Heart Development Timeline.jpg|center|850px]]<br /> <br /> <br /> The heart primordium arises predominantly from '''splanchnic mesoderm''' in the '''cardiogenic region''' of the trilaminar embryo. The cardiogenic region can be thought of as ''bilateral fields that merge cranially'' to form a horseshoe-shaped field. During the third week of development (approximately day 18) '''angioblastic cords''' develop in this cardiogenic mesoderm and canalise to form bilateral '''endocardial heart tubes'''.<br /> <br /> {|align=center<br /> |-<br /> |[[Image:Early Heart Tube (Dorsal).jpg|thumb|upright=1.5|Dorsal view of 18 day embryo]]<br /> |[[Image:Early Heart Tube (Lateral).jpg|thumb|upright=2|Lateral view of 18 day embryo]]<br /> |}<br /> <br /> Lateral folding of the embryo brings the heart tubes into the ventral midline, allowing them to fuse to form a single primordial heart tube. Fusion of the heart tubes begins cranially and extends caudally and is facilitated by '''apoptosis'''. The animation below shows a cross section of the embryo and the development of the endocardial heart tubes as well as their migration and fusion in the midline.<br /> <br /> <br /> &lt;Flowplayer height=&quot;564&quot; width=&quot;720&quot; autoplay=&quot;false&quot;&gt;Heart folding 003.flv&lt;/Flowplayer&gt;<br /> <br /> <br /> {|style=&quot;float:right&quot;<br /> |-<br /> |[[Image:Heart Tube Fusion.jpg|thumb|left|upright=1.5|Brightfield images showing fusion of the heart tubes and the earliest appearance of segments of the fused heart tube]]<br /> |[[Image:Heart Tube Segments.jpg|thumb|right|upright=1.5|Early divisions of the heart tube]]<br /> |}<br /> <br /> <br /> After fusion, ''constrictions and dilations'' appear in the heart tube, forming the following divisions (listed from cranial to caudal position):<br /> <br /> * '''Truncus arteriosus'''<br /> * '''Bulbus cordis'''<br /> * '''Primordial ventricle'''<br /> * '''Primordial atrium'''<br /> * '''Sinus venosus'''<br /> <br /> The sinus venosus is also divided into two parts: the right horn of the sinus venosus and the left horn of the sinus venosus.<br /> <br /> <br /> By day 22, coordinated contractions of the heart tube are present and push blood cranially from the sinus venosus.<br /> <br /> <br /> In the previous animation you saw that the '''dorsal aortae''' develop concurrently with the endocardial heart tubes and form a cranial connection with the endocardial heart tubes prior to folding. As the embryo folds, the cranial ends of the dorsal aortae are pulled ventrally until they form a dorsoventral loop: the first '''aortic arch arteries'''. The embryonic vascular system is discussed in further detail [[Intermediate_-_Vascular_Overview|here]].<br /> <br /> ==Heart Layers==<br /> <br /> '''''Myocardium:''''' forms from splanchnic mesoderm surrounding the '''pericardial coelom'''. Additional myocardial cells are added to the outflow tract during heart looping.<br /> <br /> '''''Cardiac Jelly:''''' gelatinous '''connective tissue''' separating the myocardium and heart tube '''endothelium'''.<br /> <br /> '''''Endocardium:''''' forms from the endothelium of the heart tube.<br /> <br /> '''''Epicardium:''''' develops from mesothelial cells arising from the sinus venosus which spread cranially over the myocardium.<br /> <br /> <br /> [[Image:Heart Tube (Cross-Section).jpg|thumb|center|upright=2|Cross-section through the ventricular section of the heart tube]]<br /> <br /> <br /> {| width=&quot;100%&quot;<br /> |-<br /> |width=&quot;30%&quot; bgcolor=&quot;gold&quot;|&lt;big&gt;'''[[Intermediate_Cardiac_Embryology|Back to the intermediate homepage]]'''&lt;/big&gt;<br /> |<br /> |width=&quot;30%&quot; bgcolor=&quot;gold&quot; align=&quot;right&quot;|&lt;big&gt;'''[[Intermediate_-_Heart_Tube_Looping|Next: Looping of the Heart Tube]]'''&lt;/big&gt;<br /> |-<br /> |bgcolor=&quot;limegreen&quot;|&lt;big&gt;'''[[Basic_-_Primitive_Heart_Tube|Go to this section in the basic level]]'''&lt;/big&gt;<br /> |<br /> |bgcolor=&quot;#FF6666&quot; align=&quot;right&quot;|&lt;big&gt;'''[[Advanced_-_Heart_Tubes|Go to this section in the advanced level]]'''&lt;/big&gt;<br /> |}<br /> <br /> {{Template:Glossary}}<br /> <br /> '''Angioblastic cords:''' Groups or ‘columns’ of embryonic precursor cells which will form the walls of both arteries and veins.<br /> <br /> '''Aortic arch arteries:''' (Or pharyngeal arch arteries.) Each early developing pharyngeal arch contains a lateral pair of arteries arising from the aortic sac, above the heart, and running into the dorsal aorta. Later in development these arch arteries are extensively remodelled to form specific components of the vascular system.<br /> <br /> '''Bulbus cordis:''' A region of the early developing heart tube forming the common outflow tract, will differentiate to form three regions of the heart. <br /> <br /> '''Cardiac jelly:''' Term used in early heart development to describe the initial gelatinous or sponge-like connective tissue separating the myocardium and heart tube endothelium.<br /> <br /> '''Cardiogenic region:''' The area in the embryo where the precursor cells for heart development lie.<br /> <br /> '''Connective tissue:''' Fibrous tissue that acts to support body structures or bind other forms of tissue.<br /> <br /> '''Dorsal aortae:''' Two largest arteries either side of the midline which later fuse to form the descending portion of the aorta.<br /> <br /> '''Endocardial heart tubes:''' Two tubes formed from the cardiogenic plate in the developing embryo. These form the primordium of the truncus arteriosus, the atrium and the ventricles; later invested with myocardium.<br /> <br /> '''Endocardium:''' The epithelial membrane lining the inside surface of heart, which along with the endothelial layer forms a continuous lining of the entire cardiovascular system. The endocardium, like the majority of the heart is mesoderm in origin. <br /> <br /> '''Endothelium:''' A simple squamous epithelium lining blood vessels. <br /> <br /> '''Epicardium:''' The outer layer of heart tissue.<br /> <br /> '''Left horn of sinus venosus:''' The left side of the sinus venosus (initially symmetrical with the right) collecting blood from half of the paired veins: common cardinal veins, umbilical veins and vitelline veins. Later the left horn diminishes and becomes the small coronary sinus.<br /> <br /> '''Myocardium:''' The middle layer of the heart wall composed of cardiac muscle.<br /> <br /> '''Pericardial coelom:''' The anatomical body cavity in which the heart lies. The pericardial cavity forms in the lateral plate mesoderm above the buccopharyngeal membrane, as part of the early intraembryonic coelom. This cavity is initially continuous with the two early pleural cavities. Note the single intraembryonic coelom forms all three major body cavities: pericardial cavity, pleural cavity, peritoneal cavity.<br /> <br /> '''Primordial atrium:''' Common cavity in the upper portion of the developing heart. Later divides to form the left and right atria.<br /> <br /> '''Primordial ventricle:''' Common cavity in the lower portion of the developing heart. Later divides to form the left and right ventricles.<br /> <br /> '''Right horn of sinus venosus:''' The right side of the sinus venosus (initially symmetrical with the left) collecting blood from half of the paired veins: common cardinal veins, umbilical veins and vitelline veins. Later the right horn dilates, receiving all the veins, and becomes the sinus venarum of the right atrium.<br /> <br /> '''Sinus venosus:''' An early developmental cardiovascular structure, thin walled cavity, forming the input to developing heart which has 3 venous inputs (vitelline vein, umbilical vein, common cardinal vein). Later in heart development this structure gets incorporated into the wall of the future right atrium.<br /> <br /> '''Splanchnic mesoderm:''' Gastrointestinal tract (endoderm) associated mesoderm formed by the separation of the lateral plate mesoderm into two separate components by a cavity, the intraembryonic coelom. Splanchnic mesoderm is the embryonic origin of the gastrointestinal tract connective tissue, smooth muscle, blood vessels and contribute to organ development (pancreas, spleen, liver). The intraembryonic coelom will form the three major body cavities including the space surrounding the gut, the peritoneal cavity. The other half of the lateral plate mesoderm (somatic mesoderm) is associated with the ectoderm of the body wall. <br /> <br /> '''Truncus arteriosus:''' An embryological heart outflow structure, that forms in early cardiac development and will later divides into the pulmonary artery and aorta. Term is also used clinically to describe the malformation of the cardiac outflow pattern, where only one artery arises from the heart and forms the aorta and pulmonary artery.<br /> <br /> [[category:heart]]</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=File:Heart_Tube_(Cross-Section).jpg&diff=16967 2010-03-14T00:44:00Z

<p>Z3212774: category:Heart ILP Cross section through the ventricular portion of the heart tube, suspended from the dorsal wall by the dorsal mesocardium. Shows the layers of the heart tube.</p> <hr /> <div>[[category:Heart ILP]]<br /> <br /> Cross section through the ventricular portion of the heart tube, suspended from the dorsal wall by the dorsal mesocardium. Shows the layers of the heart tube.</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=File:Heart_Tube_Segments.jpg&diff=16964 2010-03-14T00:42:22Z

<p>Z3212774: category:Heart ILP {{Template:SEM}} As the tubular heart grows it develops dilations and constrictions which form the truncus arteriosus, bulbus cordis, primitive ventricle, primitive atrium and sinus venosus.</p> <hr /> <div>[[category:Heart ILP]]<br /> <br /> {{Template:SEM}}<br /> <br /> As the tubular heart grows it develops dilations and constrictions which form the truncus arteriosus, bulbus cordis, primitive ventricle, primitive atrium and sinus venosus.</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=File:Heart_Tube_Fusion.jpg&diff=16960 2010-03-14T00:41:26Z

<p>Z3212774: category:Heart ILP {{Template:SEM}} The primordial heart tubes fuse in the midline to form a single ventral heart tube. Fusion begins cranially and extends caudally.</p> <hr /> <div>[[category:Heart ILP]]<br /> <br /> {{Template:SEM}}<br /> <br /> The primordial heart tubes fuse in the midline to form a single ventral heart tube. Fusion begins cranially and extends caudally.</div>

Z3212774 https://embryology.med.unsw.edu.au/embryology/index.php?title=File:Early_Heart_Tube_(Dorsal).jpg&diff=16959 2010-03-14T00:40:35Z

<p>Z3212774: </p> <hr /> <div>[[category:Heart ILP]]<br /> <br /> {{Template:SEM}}<br /> <br /> Angiogenesis throughout the embryo allows for the development of angioblastic cords in the cardiogenic mesoderm of the embryo.</div>

Z3212774