GI Anatomy Review Flashcards
List layers of alimentary tract from inside to out.
- Mucosa
- (0….o) Lamina propria/ muscularis mucosa
- Submucosa
- Muscularis externa
- Serosa/adventitia
The 6 week embryo has both a ventral and dorsal side. What develops from the dorsal side? Ventral side?
Dorsal side: parietal/somatic mesoderm
Ventral side: visceral/splanchnic mesoderm
What is the mesentary?
This is where parietal and visceral mesoderm peritoneum (serosa) meet. Suspends the gut tube to the posterior abdominal wall. Allows for blood vessels and nervous structures to come through. to supply to gut tube.
Intra (anterior, visceral) peritoneum organs.
Note: MOST ANTERIOR
- stomach
- part 1 of duodenum
jejunum, ileum - cecum, appendix
transverse-sigmoid colon - gall bladder
- liver
- tail of pancreas
- spleen
secondary (retro, posterior, parietal) peritoneum
Note: Were originally intraperitoneal
most of duodenum
- ascending-descending colon
- upper rectum
- head-neck-body of pancreas
Primary (posterior, parietal) peritonium
NOTE: MOST POSTERIOR
- abdominal aorta (uses the mesentary to get blood to intraperitoneum)
- inferior vena cava
- lower rectum
- anal canal
- kidneys
- suprarenal/adrenals
- ureters
Level of celiac trunk
T12
Level of superior mesenteric artery
L1
Level of inferior mesenteric artery
L3
What makes up hepatic portal vein?
splenic vein + superior mesenteric vein.
What is an intramural gland?
Invagination from the epithelium. Projection of the epithelium. Enters the gi (alimentary) tract. These are glands within the wall of the digestive tract. The circular part is the secretory component. Its secretions travel through ducts (the path, as in straight part) into the lumen of alimentary canal.
What is an extramural gland?
They are outside the alimentary tract wall. They include the liver, pancreas, etc. Circular part is the secretory unit. It has a stroma (acts like lamina propria) with connective tissues and nerves in order to support it, since it does not have the many layers surrounding the alimentary tract.
What does the mesoderm contribute?
The connective tissue, muscle, and serosa (most outer layer, then pregresses inward). Also gives rise to aorta.
What does the ectoderm contribute?
- Oro(bucco)pharyngeal membrane (stomodeum)
- Anal membrane (PROCTODEUM)
(note that both membranes deteriorate ate before birth)
What does the endoderm contribute?
Foregut, midgut, hindgut
What components does the stomodeum contribute? What about glands?
Oral cavity/mouth (lips, cheeks, gingivae, teeth, hard palate, ANTERIOR tongue). It also contributes the parotid gland.
What components does the foregut contribute? What about glands?
pharynx (posterior tongue, soft palate), Note this is not in the stomodeum!!!!
esophagus, stomach, duodenum (proximal). Glands made are sublingual, submandibular, liver, gallbladder, pancreas.
What components does the midgut contribute? What about glands?
duodenum (distal) jejunum ileum cecum-appendix ascending colon transverse colon (proximal). No glands are present at this point.
What components does the hindgut contribute? What about glands?
transverse colon (distal) descending colon sigmoid colon rectum anal canal (proximal). No glands are present at this point.
What does the proctodeum contribute?
Anal canal (distal)
What is significant about the oropharyngeal membrane and the anal membrane?
They’re the only places where endoderm meets ectoderm
Where do liver, pancreas, and gall bladder drain?
Second part of duodenum.
What does posterior part of cloaca give rise to? Anterior part?
Posterior: Anal/rectal canal
Anterior: Urinary portion and urethra
Achlasia
Affects the esophagus. Lower esophageal sphincter fails to relax, or literally just has a higher tension than it should be, so food bolus is not allowed to progress into the stomach. In addition to this, there is NO peristaltic activity present in the esphophagus…loss of upper esophageal sphincter with esophageal distention. Result: dilated esophagus. Patients present with difficulty swallowing and regurg of the food.
VIPomas
1:10000000 exceptionally rare neuroendocrine tumor located in the pancreas. Leads to excessive, unregulated vasoactive intestine peptide secretion. results in watery diarrhea that persists with fasting, stool volume exceeding 3k mL/day, and hypokalemia and dehydration.
Omphalocele
cele = seal = what happened to the gut tube. It is still sealed away. Associated with other SERIOUS issues. Reason of occurrence is that intestines do not retract from vitelline duct before birth.