Small Bowel II Flashcards
What embryo layer is the epithelial lining of digestive tract, glands (liver/pancreas) derived from?
endoderm
What embryo layer is the muscular connective tissue and all other layers of the intestine, abdominal wall, peritoneum derived from?
Splanchnic Mesoderm
What is the gross anatomical difference between the Jejunum and the Ileum
Jejunum—long vasa rectae, large plicae circulares, thicker wall, fewer arcades
Ileum—shorter vasa rectae, smaller plicae circulares, thinner wall, multiple vascular arcades
What is the activity of the Migrating myoelectric complex and whe does it happen?
moves from stomach to ileocecal valve during INTERDIGESTIVE period - cleanse bowel of secretions and debris
cycles: 75-90 min
What is the hormone that affects small bowel motility the most? when is it found at peak levels
Motilin
peak levels during phase III of MMC
What are the 3 component of the mucosal layer?
epithelium
lamina propria
Muscularis mucosa
What are the 4 main subtypes of epithelial layer?
- Goblet cells—secret mucus
- Paneth cells—secrete lysozyme, TNF, and cryptidins
- Absorptive
- Enteroendocrine - produce GI hormones
What are two aspects of microvilli that gives it great absorption potential?
- high surface area
2. glycocalyx coating
What are most small bowel obstructions caused by in the US? what about the world?
US: postoperative adhesions
World: Hernias
tumors
What is the classic triad of strangulated bowels?
leukocytosis
fever
tachycardia
severe abdominal pain
What are classic Sx of obstructed small bowel?
nausea/vomiting
distended abdomen
colicky abdominal pain
alteration in flatus and stool passage
How does bowel strangulation happen?
gas, fluid, succus (bacteria) accumulate in lumen
intramural pressure causes microvascular perfusion
intestinal ischemia, necrosis = strangulation
What is a particularly dangerous form of strangulation? give an example?
Closed loop obstruction
Volvulus
What are Sx of Complete Bowel Obstruction? (FATAL) how urgent?
very urgent Fever Abdominal pain Tachycardia Acidosis Leukocytosis
What is an Ileus?
Intestinal hypomotility WITHOUT obstruction