VI- Absorption and Secretion Electrolytes

Question 1

small intestine net

Answer 1

absorption of Na, K, Cl
secretion of bicarb

Question 2

large intestine net

Answer 2

absorption of Na and Cl
secretion of bicarb and K

Question 3

sodium transport mechanisms

Answer 3

1. sodium channels
2. hydrogen/sodium exchangers aka NHE3
3. SGLT1
4. amino acid transporter B

Question 4

chloride transport mechanism

Answer 4

1. absorbed by chloride/bicarb exchanger
2. secreted CFTR - Na and water follow

Question 5

potassium transport mechanism

Answer 5

1. absorption by being dragged with water
2. secreted bc of luminal negativity

Question 6

site of primary absorption

Answer 6

villi of small intestine for fluid and ions

Question 7

regulators of fluid transport

Answer 7

1. ENS via VIP, Ach, serotonin
2. immune system
3. endocrine system via prostaglandins and histamine

all inc opening of CFTR

Question 8

effect of opioids

Answer 8

slow down motility = inc segmentation/mixing > constipation

also cholinergic inhibitors

Question 9

causes of osmotic diarrhea

Answer 9

non-absorbable nutrient so water stays in the lumen
-disaccharide def
-pancreatic enzyme def
-nutrient binding substances
-loss of enterocytes/absorption
-bacterial overgrowth
-antacids

Question 10

causes of secretory diarrhea

Answer 10

intestinal secretion of fluid and electrolytes
-enterotoxins
-inflamm cytokines
-tumors

Question 11

causes of constipation

Answer 11

1. diet/lifestyle - fluid or fiber intake
2. GI- hernias or inflamm
3. pharma - narcotics, anticholinergics
4. endocrine - diabetes, hypothyroid, hyperPTH
5. neurogenic- neuropathy, parkinson, cerebral palsy