Small Bowel II

Question 1

What embryo layer is the epithelial lining of digestive tract, glands (liver/pancreas) derived from?

Answer 1

endoderm

Question 2

What embryo layer is the muscular connective tissue and all other layers of the intestine, abdominal wall, peritoneum derived from?

Answer 2

Splanchnic Mesoderm

Question 3

What is the gross anatomical difference between the Jejunum and the Ileum

Answer 3

Jejunum—long vasa rectae, large plicae circulares, thicker wall, fewer arcades

Ileum—shorter vasa rectae, smaller plicae circulares, thinner wall, multiple vascular arcades

Question 4

What is the activity of the Migrating myoelectric complex and whe does it happen?

Answer 4

moves from stomach to ileocecal valve during INTERDIGESTIVE period - cleanse bowel of secretions and debris

cycles: 75-90 min

Question 5

What is the hormone that affects small bowel motility the most? when is it found at peak levels

Answer 5

Motilin

peak levels during phase III of MMC

Question 6

What are the 3 component of the mucosal layer?

Answer 6

epithelium
lamina propria
Muscularis mucosa

Question 7

What are the 4 main subtypes of epithelial layer?

Answer 7

1. Goblet cells—secret mucus
2. Paneth cells—secrete lysozyme, TNF, and cryptidins
3. Absorptive
4. Enteroendocrine - produce GI hormones

Question 8

What are two aspects of microvilli that gives it great absorption potential?

Answer 8

1. high surface area

2. glycocalyx coating

Question 9

What are most small bowel obstructions caused by in the US? what about the world?

Answer 9

US: postoperative adhesions
World: Hernias
tumors

Question 10

What is the classic triad of strangulated bowels?

Answer 10

leukocytosis
fever
tachycardia
severe abdominal pain

Question 11

What are classic Sx of obstructed small bowel?

Answer 11

nausea/vomiting
distended abdomen
colicky abdominal pain
alteration in flatus and stool passage

Question 12

How does bowel strangulation happen?

Answer 12

gas, fluid, succus (bacteria) accumulate in lumen
intramural pressure causes microvascular perfusion
intestinal ischemia, necrosis = strangulation

Question 13

What is a particularly dangerous form of strangulation? give an example?

Answer 13

Closed loop obstruction

Volvulus

Question 14

What are Sx of Complete Bowel Obstruction? (FATAL) how urgent?

Answer 14

very urgent
Fever
Abdominal pain
Tachycardia
Acidosis
Leukocytosis

Question 15

What is an Ileus?

Answer 15

Intestinal hypomotility WITHOUT obstruction

Question 16

What are the abdominal and systemic causes of Ileus?

Answer 16

1. Abdominal:
Post-laparotomy
Intraabdominal inflammation/abscess
Intestinal ischemia
Retroperitoneal hemorrhage or inflammation

2. Systemic
   Electrolytes (sodium, potassium, magnesium, phosphorus)
   Metabolic (uremia, diabetic coma, systemic sepsis)
   Drugs (opiates, psychotropic agents, anticholinergic agents)