GI Development Flashcards by Echo Quinton

Label the GI system

How well did you know this?

Not at all

Perfectly

Label the Embryo (mid 3rd week)

How well did you know this?

Not at all

Perfectly

Label the embryo in early 4th week

How well did you know this?

Not at all

Perfectly

Label the image (embryo in early 4th week with the amniotic sac removed)

How well did you know this?

Not at all

Perfectly

Label the embryo at 4 weeks

Entrance to yolk sac is squished into ________

Entrance to yolk sac is squished into vitelline duct

How well did you know this?

Not at all

Perfectly

Label the diagram

What does the blue region become?

Blue region becomes the respiratory system

How well did you know this?

Not at all

Perfectly

_______ coats the endodermal tube

splanchnic mesoderm coats the endodermal tube

How well did you know this?

Not at all

Perfectly

label the layers of the primitive gut tube

How well did you know this?

Not at all

Perfectly

The pink region is _____ and becomes _______

The yellow region is _____ and becomes _______

The pink region is splanchnic mesoderm and becomes everything except for epithelium (Smooth muscle, connective tissue)

The yellow region is endoderm and becomes epithelium of intestines (mucosa)

How well did you know this?

Not at all

Perfectly

Label the mature gut

How well did you know this?

Not at all

Perfectly

Which signalling molecules are present in the gut during development?

Shh → (+)Bmp4 | (-)Smap

Bmp4 → + Shh

Smap → smooth muscle genes

How well did you know this?

Not at all

Perfectly

Label the image:

Numbers 2-6 represent aortic arches

How well did you know this?

Not at all

Perfectly

label the image of blood supply to gut

How well did you know this?

Not at all

Perfectly

What are the three arterial branches to the abdominal gut?

Celiac artery
Superior mesenteric artery
inferior mesenteric arter

How well did you know this?

Not at all

Perfectly

The _______, arising from the edge of teh neural plate gives rise to the entire peripheral nervous system, including the enteric nervous system

The neural crest cells gives rise to the entire peripheral nervous system, including the enteric nervous system

How well did you know this?

Not at all

Perfectly

The neural crest cells, arising from the ________ gives rise to the ________

The neural crest cells, arising from the edge of teh neural plate gives rise to the entire peripheral nervous system, including the enteric nervous system

How well did you know this?

Not at all

Perfectly

The enteric nervous system originates at the ________ and migrates/differentiates along the primitive gut tube

The enteric nervous system originates at the vagal neural crest and migrates/differentiates along the primitive gut tube

How well did you know this?

Not at all

Perfectly

The foregut includes (5)

Pharynx
Esophagus
Stomach
Superior half of duodenum (to Ampulla of Vater)
Celiac Trunk (abdominal foregut)

How well did you know this?

Not at all

Perfectly

The formation of _____ separates developing respiratory system from developing esophagus

The formation of tracheoesophageal septum separates developing respiratory system from developing esophagus

How well did you know this?

Not at all

Perfectly

Label the image (embryonic stomach)

How well did you know this?

Not at all

Perfectly

Why does the stomach develop curvatures?

Because the left side grows more (patterning cues) → more proliferation

How well did you know this?

Not at all

Perfectly

The gut is anchored to the dorsal body wall by a double-layer of _______ derived from the _________

The gut is anchored to the dorsal body wall by a double-layer of mesothelium (mesentery) derived from the splanchnic mesoderm

How well did you know this?

Not at all

Perfectly

Functions of the mesenteries?

Anchoring and organization

Conduit for vasculature/lymphatics/nerves

How well did you know this?

Not at all

Perfectly

Difference between the Ventral and Dorsal mesenteries?

Ventral mesentery
- _____ only
- Chunk of _______ associated with heart tissue (________) that gave rise to the _______ (over which the diaphragm formed)
Dorsal Mesentery
- _________

Ventral mesentery
- Foregut only
- Chunk of splanchnic mesoderm associated with heart tissue (cardiogenic mesoderm) that gave rise to the septum transversum (over which the diaphragm formed)
Dorsal Mesentery
- Runs length of gut (Abdomen to rectum)

How well did you know this?

Not at all

Perfectly

How is the Omental bursa/Lesser sac formed?

* An invagination of coelomic epithelium in the mesoderm on the right side gives rise to a recess that expands to the left and posterior/dorsal to the stomach

As the omental bursa grows, the ________ also grows

As the omental bursa grows, the _mesoderm associated with the greater curvature_ also grows = greater omentum

What is the omental bursa/lesser sac?

The omental bursa or lesser sac is **a hollow space that is formed by the greater and lesser omentum and its adjacent organs**

the lesser sac/omental bursa communicates with the greater sac via the \_\_\_\_\_\_\_\_

the lesser sac/omental bursa communicates with the greater sac via the _epiploic foramen of winslow,_

The expanding mesoderm that grows with the bursa creates the \_\_\_\_\_\_\_

The expanding mesoderm that grows with the bursa creates the _greater omentum (apron)_

Function of greater omentum?

“Policeman of Abdomen” → walls off infection, forms adhesions and locks spread Conduit for immune cells

The Midgut includes: (8) Vasculature?

* Inferior half of duodenum * Jejunum * Ileum * Cecum * Appendix * Ascending colon * Right ⅔rds of transverse colon Superior mesenteric artery

The _______ occurs at the base of the umbilical cord where body folding converges

The _midgut herniation_ occurs at the base of the umbilical cord where body folding converges

At the base of the umbilical cord where body folding converges there is a ______ coated by \_\_\_\_\_\_

At the base of the umbilical cord where body folding converges there is a _connecting stalk_ coated by _membrane of amnion_

Label the image:

What development happens during midgut herniation?

The small intestine increases 20x in length Large intestine increases 8x As it grows, bending/folding/coiling =\> loops

Label the current model of midgut movement (during herniation)

How is the midgut returned to the abdomen? Label the image:

At approximately 10-11 weeks the **abdomen enlarges** and the intestines return to the abdominal cavity. The midgut then rotates an additional 180 degrees counter-clockwise, fixing to the posterior retroperitoneum

What happens with the obliteration of the vitelline duct?

Yolk sac is released into the amniotic cavity

Which organs are secondarily retroperitoneal viscera (stuck on posterior body wall)?

* Duodenum * Pancreas * Ascending colon * Descending colon

Which organs are retroperitoneal viscera (outside the peritoneum)?

* Thoracic esophagus * Rectum

How do the duodenum, pancreas, ascending colon and descending colon (which all start as intraperitoneal) move to a secondarily retroperitoneal viscera position?

* Started intraperitoneal then squished to posterior layer of somatic mesoderm → gives rise to parietal peritoneum → grows over → stuck to wall → anchor points

Which organs are intraperitoneal viscera?

* Abdominal esophagus * Liver * Gallbladder and bile duct * Stomach * Transverse colon * jejunum and ileum * Cecum * Appendix * Sigmoid colon

How does the anterior body wall change with return of herniation (from 6 weeks to 9 weeks)?

* The abdominal gap (diastasis) is closed because the rest of the body grows making the gap appear smaller

What are the organs of the hindgut and what artery supplies them?

* Left ⅓ of transverse colon * Descending colon * Sigmoid colon * Rectum * Superior portion of anal canal Supplied by Inferior Mesenteric Artery

What divides the cloaca at about 28-32 days?

The **Urorectal septum** Divides into the anterior urogenital sinus and posterior rectum

What is on the anterior side of the urorectal sinus? The Posterior?

* Anterior → Urogenital sinus and allantois (finger of endoderm protruding into the umbilical cord) * Posterior → Rectum

By 7 weeks, the _____ has grown into the cloacal membrane and completely divided the anterior and posterior portions of the cloaca. At that point, what happens?

By 7 weeks, the _urorectal septum_ has grown into the cloacal membrane and completely divided the anterior and posterior portions of the cloaca. At that point, what happens? * The membrane ruptures opening the lower GI and urinary tracts to the amniotic cavity (septum breaks down the cloacal membrane)

What happens at the anal canal after the cloacal membrane bursts (following urorectal growth)?

* The ectoderm around the opening to the anus proliferates, creating a temporary plug (center cells) * The central cells of the plug undergo *apoptosis* creating a new opening * Therefore, the lower part of the anal canal is derived from **ectoderm** not endoderm

The lower part of the anal canal is derived from \_\_\_\_\_\_\_, why?

The lower part of the anal canal is derived from _ectoderm (not endoderm)_, why?f because the ectoderm around the opening to the anus proliferates, creating a temporary plug, the central cells of this plug undergo apoptosis creating a new opening

What divides the ectoderm (inferior) and endoderm-derived (superior) portions of the anal canal?

The ectoderm and endoderm-derived portions of the anal canal are divided by the *pectinate line* (tooth-like appearance)

What is the importance of the pectinate line in terms of hemorrhoids classification?

* Internal hemorrhoids * Above pectinate line (endoderm-derived) * Not painful * External hemorrhoids * Below pectinate line (ectoderm derived) * Painful

Label the chart

All digestive glands (\_\_\_\_\_\_, \_\_\_\_\_\_, \_\_\_\_\_\_\_) all start as \_\_\_\_\_\_

All digestive glands (_liver, pancreas, gall bladder_) all start as _evaginations of the primitive gut tube_

Liver starts as an ______ that grows ______ just below the \_\_\_\_\_\_

Liver starts as an _evagination_ that grows _ventrally (into ventral mesentery4)_ just below the _stomach_

The liver and gall bladder start as _______ surrounded by \_\_\_\_\_\_

The liver and gall bladder start as _pockets of endoderm_ surrounded by _splanchnic mesoderm_

What makes the function regions of the liver and gall bladder?

Endoderm

What are the three phases of liver development?

* Liver diverticulum * Liver bud initiation * Liver bud hepatic hematopoiesis

What gives rise to blood vessels during liver development?

Endothelial cells

What are the liver progenitor cells?

Hepatoblasts

The Hepatic progenitors, \_\_\_\_\_\_\_, are derived from ______ and make the \_\_\_\_\_\_\_\_

The Hepatic progenitors, _hepatoblasts_, are derived from _endoderm_ and make the _functional cells (hepatocytes and cholangiocytes)_

Splanchnic mesoderm makes ______ (liver)

Splanchnic mesoderm makes stroma/smooth muscle

How does the pancreas develop? * Starts as _____ which are pockets off primitive gut tube on ventral and dorsal side * Grow off the _____ into ______ and off _____ side into the \_\_\_\_\_ * Pushed together during development onto ______ side of gut tube

How does the pancreas develop? * Starts as _pancreatic buds_ which are pockets off primitive gut tube on ventral and dorsal side * Grow off the _ventral side_ into _ventral mesentery_ and off _dorsal_ side into the _dorsal mesentery_ * Pushed together during development onto _left_ side of gut tube

Where is the head of the pancreas located?

Head of pancreas tucked into the bend of the duodenum (C-shape pushed against posterior wall)

Connection for pancreas join at \_\_\_\_\_\_

Connection for pancreas join at _bile ducts_

Pancreas develops with ______ inside and _____ outside

Pancreas develops with _endoderm_ inside and _splanchnic mesoderm_ outside Endoderm → functional cells and ducts Splanchnic mesoderm → CT/ smooth muscle/stroma