Physiology

Question 1

How do pancreatic enzymes get activated and not digest pancreas?

Answer 1

1. Fats/Proteins enter
2. CCK from I cells of duodenum/jejunum activate pancreas
3. Pancreas secretes Trypsinogen
4. Trypsinogen activated to trypsin at brush border by enterokinase

Question 2

What do chief cells do?

Answer 2

Secrete pepsinogen, which is activated to pepsin by HCl in stomach

Question 3

Where is somatostatin produced?

Answer 3

pancreatic delta cells, gastric antrum (reason for ulcers from H. pylori)

Question 4

Pancreatic endocrine tumors

Answer 4

Glucagonoma (alpha cells) - hyperglycemia, rash
Insulinoma (beta cells) - hypoglycemia
Somatostatinoma (delta cells) - hyperglycemia, diarrhea, gallstone
VIPoma - Watery diarrhea, hypokalemia, achlorydria
Gastrinoma - secretin paradoxically increases gastrin

Question 5

Intestinal atresias

Answer 5

Duodenal - Down syndrome - recanalization problem (non-bilious)
Jejunal/Ileal - Gastroschisis vascular injury - bilious
Colon - Hirschsprung

Question 6

Acute hepatitis (like with halothane)

Answer 6

Elevated LFTs + Prothrombin time (synthetic dysfn)

Question 7

Difference between anatomy of external hemmorrhoids and internal hemmorrhoids?

Answer 7

Inferior hemorrhoids - columnar epithelium, autonomic strech receptors from inferior hypogastric plexus, cirrhosis to superior rectal vein (portal system), drainage to internal iliac nodes

External hemorrhoids - squamous cell, pudendal nerve painful innervation, pushing, inferior rectal vein to vena cava, superficial inguinal node

Question 8

What vitamins do gut bacteria produce?

Answer 8

Vit K and folate

Question 9

Why does crohn’s cause oxalate stones?

Answer 9

1. Bile acids can’t be absorbed in terminal ileum
2. Fats can’t be absorbed because no bile acids
3. Calcium usually binds to oxalate in gut, but now binds to fats
4. Free oxalate is absorbed and goes to kidney