2010 Lab 5

From Embryology

Introduction

This laboratory will allow time to study both gastrointestinal tract and respiratory development. The class will study features and events of development occurring: early-embryonic, mid-embryonic, late-embryonic and fetal. Both these systems do not carry out their postnatal function before birth. Though during the fetal period both these systems "prepare" for their postnatal functions. Clinically even in normal development the respiratory system only matures towards the end of the third trimester, leading to respiratory problems with premature infants.

In this lab we will use animations to observe some developmental events and then look within the embryo and fetus at different periods of development.

The materials used in this class can also be seen at the following links: Gastrointestinal Tract - Carnegie Stage 13 | Stage 22 | Respiratory System - Carnegie Stage 13 | Respiratory System - Carnegie Stage 22 | Fetal Development - 10 Weeks | Gastrointestinal Tract Lecture | Respiratory Lecture | Flash movies | Quicktime movies

Related notes pages

GIT Links: Introduction | Medicine Lecture | Science Lecture | endoderm | mouth | oesophagus | stomach | liver | gallbladder | Pancreas | intestine | mesentery | tongue | taste | enteric nervous system | Stage 13 | Stage 22 | gastrointestinal abnormalities | Movies | Postnatal | milk | tooth | salivary gland | BGD Lecture | BGD Practical | GIT Terms | Category:Gastrointestinal Tract
GIT Histology Links: Upper GIT | Salivary Gland | Smooth Muscle Histology | Liver | Gallbladder | Pancreas | Colon | Histology Stains | Histology | GIT Development
Historic Embryology - Gastrointestinal Tract  
1878 Alimentary Canal | 1882 The Organs of the Inner Germ-Layer The Alimentary Tube with its Appended Organs | 1902 The Organs of Digestion | 1903 Submaxillary Gland | 1906 Liver | 1907 Development of the Digestive System | 1907 Atlas | 1907 23 Somite Embryo | 1908 Liver and Vascular | 1910 Mucous membrane Oesophagus to Small Intestine | 1910 Large intestine and Vermiform process | 1911-13 Intestine and Peritoneum - Part 1 | Part 2 | Part 3 | Part 5 | Part 6 | 1912 Digestive Tract | 1912 Stomach | 1914 Digestive Tract | 1914 Intestines | 1914 Rectum | 1915 Pharynx | 1915 Intestinal Rotation | 1917 Entodermal Canal | 1918 Anatomy | 1921 Alimentary Tube | 1932 Gall Bladder | 1939 Alimentary Canal Looping | 2008 Liver | 2016 GIT Notes | Historic Disclaimer
Human Embryo: 1908 13-14 Somite Embryo | 1921 Liver Suspensory Ligament | 1926 22 Somite Embryo | 1907 23 Somite Embryo | 1937 25 Somite Embryo | 1914 27 Somite Embryo | 1914 Week 7 Embryo
Animal Development: 1913 Chicken | 1951 Frog
Respiratory Links: respiratory | Science Lecture | Lecture Movie | Med Lecture | Stage 13 | Stage 22 | upper respiratory tract | diaphragm | Histology | Postnatal | respiratory abnormalities | Respiratory Quiz | Respiratory terms | Category:Respiratory
Historic Embryology  
1902 The Nasal Cavities and Olfactory Structures | 1906 Lung | 1912 Upper Respiratory Tract | 1912 Respiratory | 1914 Phrenic Nerve | 1918 Respiratory images | 1921 Respiratory | 1922 Chick Pulmonary Vessels | 1934 Right Fetal Lung | 1936 Early Human Lung | 1937 Terminal Air Passages | 1938 Human Histology

Gastrointestinal Tract Movies

Endoderm 002 icon.jpg Amnion 001 icon.jpg Gastrointestinal tract growth 01 icon.jpg Stomach rotation 01 icon.jpg Lesser sac 01 icon.jpg Greater omentum 001 icon.jpg Urogenital septum 001 icon.jpg
Endoderm Yolk Sac Tract Growth Stomach Rotation Lesser Sac Greater Omentum Urogenital Septum
Quicktime version Quicktime version Quicktime version Quicktime version Quicktime version Quicktime version Quicktime version

Gastrointestinal Tract and Respiratory - Mid-Embryonic (Stage 13)

Begin by studying the 3d model and getting an idea of the position within the embryo of the gastrointestinal tract, its associated organs and the early lung buds.

Then look through the selected sections and identify these structures in relation to the surrounding organs and tissues.

Finally compare this mid-embryonic organisation and structure with that seen at the end of the embryonic period (Stage 22). What has changed?

(MH - Note it is best to open each image in a new browser Tab)

Stage14 respiratory tract.jpg Stage13-GIT-icon.jpg

Gastrointestinal and Respiratory

The individual serial slices below have been incorporated into a 3D model of this embryo.


Respiratory Links: respiratory | Science Lecture | Lecture Movie | Med Lecture | Stage 13 | Stage 22 | upper respiratory tract | diaphragm | Histology | Postnatal | respiratory abnormalities | Respiratory Quiz | Respiratory terms | Category:Respiratory
Historic Embryology  
1902 The Nasal Cavities and Olfactory Structures | 1906 Lung | 1912 Upper Respiratory Tract | 1912 Respiratory | 1914 Phrenic Nerve | 1918 Respiratory images | 1921 Respiratory | 1922 Chick Pulmonary Vessels | 1934 Right Fetal Lung | 1936 Early Human Lung | 1937 Terminal Air Passages | 1938 Human Histology
Stage 13 - Gastrointestinal Tract
Section Name Description
Stage 13 image 057.jpg

Stage 13 image 058.jpg

B1L


B2L

Pharynx

Head arches cartoon.jpg Note how in this region it is arched over and cut twice in this section.

The righthand side towards the buccopharyngeal membrane, the lefthand side descending into the embryo body. Stage13 B2 excerpt.gif

Central region is the floor of pharynx formed by fusion of 3rd pharyngeal arches = hypopharyngeal eminence (precursor of root of tongue).

Rathke's pouch forming the rudimentary adenohypophysis (anterior pituitary).

Stage 13 image 059.jpg B3L Laryngeal tracheal groove - beginning of ventral compression, at 90 degrees to the lateral plane of the pharynx above this point.

Rudimentary thyroid ventral to aortic sac (also seen in B2, ventral to the hypopharyngeal eminence).

Stage 13 image 060.jpg B4L Laryngeal tracheal groove - Caudal pharynx compressed dorsoventrally.

Note that it lies between the aortic sac (ventrally) directly above the heart and the paired vessels of arch artery 6 and the dorsal aortas. The pale staining region behind these blood vessels is where the vertebral column will form.

Stage 13 image 061.jpg B5L Laryngopharynx - now compressed dorsoventrally between the paired arch artery 6 vessels.
Stage 13 image 063.jpg B7L Glottis - initial separation of the oesophagus (dorsal) from the trachea (ventral).

Note that this is occurring at the level of the heart atria.

Nasal placodes. Pulmonary arteries.

Stage 13 image 064.jpg C1L Gastrointestinal tract oesophagus (dorsal) is now separate from the respiratory trachea (ventral).
Stage 13 image 065.jpg C2L Oesophagus and trachea both surrounded by dense mesenchyme.

Right nasal pit.

Stage 13 image 066.jpg

Stage 13 image 067.jpg

C3L

C4L

Oesophagus and trachea both surrounded by dense mesenchyme.

Common cardinal vein in the posterior wall of the intraembryonic coelom.

The pleuropericardial folds which contribute later to the formation of the pleura and pericardium.

In C4, junction of right common cardinal vein with dorsal wall of sinus venosus.

Left nasal pit.

Stage 13 image 068.jpg C5L Smaller oesophagus and expanding trachea, this is also the upper region of the lung buds.

The ventral anchoring of attachment site is at the most cranial extension of the septum transversum. This attachment now divides the intraembryonic coelom around the trachea into two canals, the left and right pleuro (pericardio-peritoneal) canals.

Canals are lined by coelomic mesothelium and are continuous with whole intraembryonic coelom (they will be referred to hereafter simply as coelomic canals).

The pleuroperitoneal fold on the medial side of the right common cardinal vein will form part of the diaphragm.

Stage 13 image 069.jpg C6L Trachea expanded and beginning to bifurcate to the major bronchial branches for each lung.

Lateral extension of pulmonary mesenchyme is moulded to shape of coelomic canals. Oesophagus lumen obliterated (common site of oesophageal atresia and/or tracheo-oesophageal fistula). Prominent R pleuroperitoneal fold.

Stage 13 image 070.jpg C7L Trachea bifurcated to the major bronchial branches for each lung.

Note dorsal extent of coelomic canals.

Oesophagus lumen reappears caudal to bifurcation.

Distinct R (smaller on L) pleuroperitoneal fold below the common cardinal vein.

Stage 13 image 071.jpg D1L Oesophagus/stomach junction.

Right lung bud bronchus still visible, left bronchus ends above this section. Note the oesophagus now lies in the midline between the 2 bronchi.

Coelomic canals.

Stage 13 image 072.jpg D2L Ovoid stomach with developing space of the lesser sac on R.

Dorsal and ventral attachments of the mesenchyme are now known as dorsal and ventral mesogastria. Coelomic canals.

Stage 13 image 073.jpg D3L Rotation of stomach (seen from above) to right side.

Note change in outline of coelomic canals due to presence of liver.

Lesser sac. Note thick mesothelium lining the coelom along left edge of stomach, the primordium of the spleen and greater omentum along greater curvature.

Liver embedded in septum transversum (ventral border of septum transversum contributes to diaphragm).

Stage 13 image 074.jpg D4L Rotation of stomach (seen from above) to right side.

Ventral mesogastrium - Stomach is attached ventrally to the liver. (note the position of the ductus venosus)

Dorsal mesogastrium - within this structure the spleen will begin to form and later the greater omentum.

Peritoneal spaces - identify greater and lesser sac.

Stage 13 image 076.jpg D6L Pyloric region of stomach.

Ventral mesogastrium - Stomach is closely attached ventrally to the liver.

Dorsal mesogastrium - within this structure the spleen will begin to form and later the greater omentum.

Peritoneal spaces - identify greater and lesser sac.

Stage 13 image 081.jpg E4L Midgut.

Region close to the umbilicus. Note the close associated portal vein and the paired placental (umbilical) veins.

Stage 13 image 085.jpg F1L Midgut.

Looping out of body wall ventrally (cut tangentially).

Also note the righthand side hindgut region.

Stage 13 image 098.jpg G7L Caudal pharynx (extending laterally, ventral to dorsal aorta - cf B4). Stomach, mesentery
Stage 13 image 097.jpg G6L Narrow oesophagus. Tracheal bifurcation dorsal to sinus venosus.

Gastrointestinal Tract - Late-Embryonic (Stage 22)

Stage22-GIT-icon.jpg

Gastrointestinal

The individual serial slices have also been incorporated into a 3D model of this embryo.
Stage 22 - Gastrointestinal Tract
Section Name Description
Stage 22 image 083.jpg E6L Liver. Ductus venosus.

Cardio-oesophageal junction (cf. E5).

Inferior vena cava.

Stage 22 image 084.jpg E7L Stomach body, with mucosa, submucosa and muscularis externa.

Lesser sac. Lesser omentum. Pyloroduodenal junction. Folded duodenal mucosa.

Inferior vena cava. Portal vein. Hepatic ducts. Gallbladder.

Stage 22 image 085.jpg F1L Stomach body. Spleen. Pyloric canal. Duodenum.

Pancreas.

Small intestine loop (jejunum) cut tangentially, ventral to liver.

Portal vein.

Stage 22 image 086.jpg

Stage 22 image 087.jpg

F2L


F3L

Stomach, spleen. Superior mesenteric artery.

Superior mesenteric vein crossing cranial to body of pancreas.

Tail of pancreas.

Duodenum.

Small intestinal loop herniating from abdominal cavity into the coelom of the umbilical cord (remnant of extra-embryonic coelom).

Stage 22 image 088.jpg F4L Greater curvature of stomach (tangential section). Lesser sac. Greater omentum. Duodenal/jejunal junction.

Note colon (small lumen, darkly-staining wall) and its mesocolon.

Note the sections of small and large intestine within the umbilical cord coelom and their mesenteries.

Note the thickened jelly to one side of the umbilical cord, containing umbilical vein and R umbilical artery.

Stage 22 image 089.jpg F5L Lesser sac. Greater omentum. Duodenum. Jejunum (cut twice with mesentery in between). Colon and mesocolon.
Stage 22 image 090.jpg F6L Greater omentum and lesser sac.

Jejunum with mesentery.

Colon with mesocolon.

Three layers of abdominal muscles.

Both umbilical arteries now inside abdominal cavity with urachus between them.

Stage 22 image 091.jpg F7L In abdominal cavity - colon with mesocolon, jejunum. Greater omentum and lesser sac.

Umbilical cord - containing umbilical arteries and small dark allantois. Umbilical cord coelom containing mainly, small intestinal loops with their mesentery.

Stage 22 image 092.jpg

Stage 22 image 093.jpg

G1L


G2L

Umbilical cord and coelom containing small intestine loops.

Colon and mesocolon. Jejunum (G1 only).

Bladder with umbilical arteries either side.

Knees.

Stage 22 image 094.jpg G3L Rectum.

Bladder.

Umbilical arteries arising from common iliac arteries.

Stage 22 image 095.jpg G4L Rectum.
Stage 22 image 096.jpg G5L Recto-anal junction with rectovesical pouch of peritoneal cavity.
Stage 22 image 097.jpg

Stage 22 image 098.jpg

G6L

G7L

Anal canal with triangular lumen.

Respiratory - Late-Embryonic (Stage 22)

Stage22-GIT-icon.jpg

Respiratory

The individual serial slices have also been incorporated into a 3D model of this embryo.

The respiratory system is endodermal in origin, initially "budding off" the foregut during week 3. This bud forms the respiratory diverticulum, at the level of the glottis between the adult oesophagus and trachea. It continues to bud in week 4, forming a pair of lung buds.

Respiratory Links: respiratory | Science Lecture | Lecture Movie | Med Lecture | Stage 13 | Stage 22 | upper respiratory tract | diaphragm | Histology | Postnatal | respiratory abnormalities | Respiratory Quiz | Respiratory terms | Category:Respiratory
Historic Embryology  
1902 The Nasal Cavities and Olfactory Structures | 1906 Lung | 1912 Upper Respiratory Tract | 1912 Respiratory | 1914 Phrenic Nerve | 1918 Respiratory images | 1921 Respiratory | 1922 Chick Pulmonary Vessels | 1934 Right Fetal Lung | 1936 Early Human Lung | 1937 Terminal Air Passages | 1938 Human Histology

| Carnegie stage 22


Stage 22 (serial labeled images)
Section Name Description
Stage 22 image 054.jpg A5L Bridge of nose.

R and L olfactory bulbs from forebrain.

Stage 22 image 055.jpg A6L Nose. Nasal septum. Nasal capsule.

Olfactory epithelium lining roof of nasal cavity.

Orbital part of the developing sphenoid bone (intramembranous ossification).

Stage 22 image 056.jpg A7L Conchae. Nasal capsule and septum.
Stage 22 image 057.jpg B1L Conchae. Optic nerve.
Stage 22 image 058.jpg B2L Description
Stage 22 image 059.jpg B3L Perpendicular plate of ethmoid cartilage. Adenohypophysis. Neurohypophysis. Ant. and post. walls of hypopophysial fossa. Lesser wings of sphenoid cartilage. Internal carotid arteries.
Stage 22 image 060.jpg B4L Dorsum of tongue. Oropharynx communicating with naso-pharynx (cf. B3L - palatal processes not fused).
Stage 22 image 061.jpg B5L Tongue with palatal processes at either side. Transverse (intrinsic) muscle of tongue.

Pharyngotympanic tubes.

Stage 22 image 062.jpg B6L Tongue with transverse muscle, genioglossus muscle (medial) and hyoglossus muscle (lateral).

Palatal processes.

Meckel's cartilage. Note teeth enamel organs (dark masses at sides of tongue attachment).

Stage 22 image 063.jpg B7L Transverse caudal pharynx. epiglottis. Hyoid musculature. Pharyngeal constrictor muscle. Submandibular gland.
Stage 22 image 064.jpg C1L Pharynx. Pharyngeal constrictor muscle. laryngeal caecum (ventral). Arytenoid swellings in contact.

Thyroid cartilage laminae (anterolateral), with superior horns (posterolateral). Hyoid cartilage. Internal jugular veins.

"Muz's cheshire cat"

Stage 22 image 065.jpg C2L Pharynx. Thyroid cartilage. Smaller laryngeal caecum (cf.C1). Carotid neurovascular bundle.
Stage 22 image 066.jpg C3L Pharynx with its inferior constrictor muscle. Glottis region.
Stage 22 image 067.jpg C4L Oesophagus with muscle layer and trachea with thyroid gland laterally.

Common carotid arteries. Vagus nerve. Internal jugular veins.

(Section damaged)

Stage 22 image 068.jpg C5L Oesophagus, smaller than in C4. Trachea.

Thyroid gland (isthmus). Clavicle. Small dark masses near posterolateral borders of thyroid gland are the parathyroid glands from the caudal part of 3rd pharyngeal pouch.

Stage 22 image 069.jpg C6L Trachea.

Clavicles. Dark connecting stalk between parathyroid gland and thymus (rostral end of 3rd pharyngeal pouch).

Common carotid artery.

Stage 22 image 070.jpg C7L Trachea.

Oesphagus. Apex of R lung in pleural cavity

Sternum. Thymus gland. L brachiocephalic vein. Brachiocephalic trunk.

Stage 22 image 071.jpg D1L Lungs. Visceral and parietal pleurae. Pleural cavities.

Sternum. Thymus.

Other contents of superior mediastinum.

Stage 22 image 072.jpg D2L Lungs.
Stage 22 image 073.jpg D3L Tracheal bifurcation.
Stage 22 image 074.jpg D4L Right primary bronchus (torn) and right superior lobe bronchus.

Left primary bronchus.

Left and right pulmonary arteries.

Ribs joining to sternum.

Stage 22 image 075.jpg D5L R, L primary bronchi. R anterior and posterior segmental bronchi coming off R superior lobe bronchus. L, R pulmonary arteries. Hilar attachments of lungs to mediastinal tissues - note extent of R, L pleural cavities.
Stage 22 image 076.jpg D6L R, L primary bronchi (note left still has not branched). R pulmonary artery.
Stage 22 image 077.jpg D7L R, L primary bronchi: note distinct horizontal course of L, vertical course of R, L pulmonary veins (L empty). R pulmonary artery.
Stage 22 image 078.jpg E1L Pulmonary veins. Azygos, hemiazygos veins. Ribs. Intercostal muscles.
Stage 22 image 079.jpg E2L Pulmonary veins. Azygos, hemiazygos veins. Ribs. Intercostal muscles.
Stage 22 image 080.jpg E3L R dome of diaphragm. R long middle and inferior lobes. L long superior and inferior lobes. Xiphoid process.

Liver.

Stage 22 image 081.jpg E4L Diaphragm (note costal attachment). R lung inferior lobe.

Inferior vena cava, dorsal to diaphragm.

Stage 22 image 082.jpg E5L Inferior lobes of lungs.

Diaphragm with sternal attachments.

Inferior vena cava, now ventral to diaphragm (vena caval foramen).

Liver.

Stage 22 image 083.jpg E6L Liver. Thoracic aorta. Large adrenal glands.
Stage 22 image 084.jpg E7L Lumbar diaphragm. Thoracic aorta. Note ribs 11 and 12 on L and three layers of abdominal muscles extending ventrally.
Stage 22 image 085.jpg F1L Lumbar diaphragm. Thoracic aorta.
Stage 22 image 086.jpg F2L Attachment of lumbar diaphragm near L 1 on R with psoas muscle dorsal to it. Note abdominal aorta giving rise to superior mesenteric artery.

Early Fetal (Week 10)

The fetal period is a time of extensive growth in size and mass as well as differentiation of organ systems established in the embryonic period. In particular, the brain continues to grow and develop, the respiratory system differentiates, the urogenital system further differentiates between male/female, endocrine and gastrointestinal tract begins to function.

These 4 images are from a 10 week female fetus approximately 40 mm in size. This stage of development is after the embryonic period (up to week 8), but only 2 weeks into early fetal development.

Compare this 10 week fetus with the earlier Carnegie stage embryos in relation to gastrointestinal tract and respiratory development.

Note:

  1. The structure, size and position of the early fetal lungs.
  2. The relatively underdeveloped diaphragm.
  3. The position of the stomach and liver.
  4. The midgut herniated at the umbilicus and will only be taken into the peritoneal cavity on further body wall growth.
  5. The herniated midgut remains attached to the posterior body wall by its mesentery.
  6. The hindgut rectum is now separated from the ventral urogenital region.
Fetal Links: fetal | Week 10 | Week 12 | second trimester | third trimester | fetal neural | Fetal Blood Sampling | birth weight | Developmental Origins of Health and Disease | fetal growth restriction | macrosomia | BGD Practical | Medicine Lecture | Science Lecture | Lecture Movie | preterm birth | birth | Category:Human Fetus | Category:Fetal
Historic Embryology  
1940 Fetus Physiology
Carnegie Fetal: 95 | 96 | 142 | 145 | 184 | 211 | 217 | 300 | 362 | 448 | 449 | 538 | 590 | 607 | 625 | 662 | 693 | 847 | 858 | 922 | 928 | 948 | 972 | 1318 | 1388 | 1455 | 1591 | 1597b | 1656 | 1686 | 2250a | 2250b | 3990 | 5652 | 6581 | 7218

There are 4 sections taken in the sagittal plane (moving from the right at Plane A towards the midline at Plane D). Click on the small images (or the text below) to open the linked large image pages.

Related Images

Human- fetal week 10 planes icon.jpg

Fetus (week 10) Planes A (most lateral), B (lateral), C (medial) and D (midline) from lateral towards the midline.

Image Source: UNSW Embryology, no reproduction without permission.


Fetal Tract Development

Week 11 - villi begin to appear in small intestine, goblet cells present

Week 16 - villi apparent in entire intestine

Adult small intestine will be divided into 3 regions with the same basic histological organization: duodenum (25-30 cm), jejunum (about first two-fifths of the rest), ileum

Week 20 - Peyer's patches appear in small intestine

The adult intestinal immune system includes: Peyer's patches, isolated lymphoid follicles, cryptopatches, mesenteric lymph nodes

Group Project

  • There should now be major sub-headings on the project page and commencing to populate each section.
  • The discussion page should have images and resources either uploaded or linked for your project page.
  • What is the student drawn figure(s) and who is doing it?
  • Do you have your references collected and have you identified the PMID for each reference so that it will format correctly on the project page.