File:Heart1 atrium.gif

From Embryology

Heart1_atrium.gif(350 × 373 pixels, file size: 243 KB, MIME type: image/gif, looped, 19 frames, 11 s)

Atrial Septation Animation

This animation summarises early cardiac atrial septation. This process is complex and results in a channel which allows the majority of blood to shunt from one atria to the other atria, bypass the developing pulmonary system. This channel will remain open through embryonic and fetal development until after birth.

Blue - septum primum | Green - septum secundum | Red - blood flow

Atrial Septum Links: MP4 version | Quicktime version | Animated GIF version | Tutorial - Septation of the Atria | Advanced - Cardiac Septation | Atrial Septal Defects

Cardiovascular Links: cardiovascular | Heart Tutorial | Lecture - Early Vascular | Lecture - Heart | Movies | 2016 Cardiac Review | heart | coronary circulation | heart valve | heart rate | Circulation | blood | blood vessel | blood vessel histology | heart histology | Lymphatic | ductus venosus | spleen | Stage 22 | cardiovascular abnormalities | OMIM | 2012 ECHO Meeting | Category:Cardiovascular
Historic Embryology - Cardiovascular 
1902 Vena cava inferior | 1905 Brain Blood Vessels | 1909 Cervical Veins | 1909 Dorsal aorta and umbilical veins | 1912 Heart | 1912 Human Heart | 1914 Earliest Blood-Vessels | 1915 Congenital Cardiac Disease | 1915 Dura Venous Sinuses | 1916 Blood cell origin | 1916 Pars Membranacea Septi | 1919 Lower Limb Arteries | 1921 Human Brain Vascular | 1921 Spleen | 1922 Aortic-Arch System | 1922 Pig Forelimb Arteries | 1922 Chicken Pulmonary | 1923 Head Subcutaneous Plexus | 1923 Ductus Venosus | 1925 Venous Development | 1927 Stage 11 Heart | 1928 Heart Blood Flow | 1935 Aorta | 1935 Venous valves | 1938 Pars Membranacea Septi | 1938 Foramen Ovale | 1939 Atrio-Ventricular Valves | 1940 Vena cava inferior | 1940 Early Hematopoiesis | 1941 Blood Formation | 1942 Truncus and Conus Partitioning | Ziegler Heart Models | 1951 Heart Movie | 1954 Week 9 Heart | 1957 Cranial venous system | 1959 Brain Arterial Anastomoses | Historic Embryology Papers | 2012 ECHO Meeting | 2016 Cardiac Review | Historic Disclaimer

Related Terms

atrial septation - Term describing the complex developmental formation of the interatrial septum, the wall between the right and left atria of the heart. In humans, this septation process begins in week 5 of development with the septum primum, a membranous extension on the dorso-cranial wall growing downward towards endocardial cushions. An opening remains as the foramen primum (ostium primum). The septum primum fuses with endocardial cushion, but cranially had begun to degenerate forming foramen secundum (ostium secundum). A later forming septum secundum on the ventro-cranial wall grows downward, but does not fuse with endocardial cushion, the remaining opening is the foramen ovale. Abnormalities of this process are called Atrial Septal Defects (ASD), a group of common (1% of cardiac) congenital anomalies occurring in a number of different forms and more often in females. The process of separating the ventricles is called ventricular septation.

atrial septal defect - (ASD) Heart developmental abnormality leading to an abnormal opening or hole in the septum between right and left atria. Normally allows left to right blood shunting, though additional cardiac abnormalities causing higher right side pressure (pulmonary stenosis or tricuspid atresia) allow right to left blood shunting.

atrium - The upper heart chamber receiving circulating blood and by contracting pumps this blood into the ventricle. The human heart has two atria; right atrium receiving deoxygenated venous (vena cava) circulating blood and left atrium receiving oxygenated blood from the lungs (pulmonary).

ostium primum - (primary opening, first opening) In early heart development during atrial septation, the initial septum primum is incomplete leaving this initial opening between the left and right atria. Later the septum primum begins to degenerate forming a second opening, the ostium secundum.

ostium secundum - (secondary opening, second opening) In early heart development during atrial septation, the initial septum primum begins to degenerate forming this second opening between the developing left and right atria.

septum primum - (primary septum) In early heart development in the atrial wall a superior region in the midline extends downward, forming the initial incomplete separation (septation) of the right and left atria leaving an opening the ostium primum. This initial structure partially breaks down forming the ostium secundum and later fuses with the septum secundum. Note that complete functional and anatomical separation of the right and left atria occurs after birth with activation of the pulmonary system.

septum secundum - (secondary septum) In early heart development, atrial septation is completed by an atrial wall growth to the right of the initial septum primum. Note that complete functional and anatomical separation of the right and left atria occurs after birth with activation of the pulmonary system.

Cite this page: Hill, M.A. (2024, June 23) Embryology Heart1 atrium.gif. Retrieved from

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© Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G

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