Gut physiology

Question 1

FLuid going in and out of gut - where is most of the fluid reabsorbed?

Answer 1

Small intestine - 7.5L per day
also colon - absorbs <1.5L per day

Question 2

How much water in faeces per day?

Answer 2

<200Ml/day excreted

Question 3

Difference between the villi and crypts in small intestine?

Answer 3

Net absorption in villi
Net secretion in crypts

Question 4

How is energy supplied to move against concentrstion gradients?

Answer 4

Proton gradients and by sodium gradients (generated by sodium pump)

Question 5

What is the basolateral side?
Apical side?

Answer 5

• side next to blood vessels (base and lateral)
• side next to lumen

Question 6

What causes movement of fluid from the cells to the gut? (secretion)

Answer 6

Chloride ion movement
Pulls positive ions - sodium
Water follows sodium

There are many reactions/transporters of the cell that regulate Cl- secretion and NA+ and otherconcentrationa

Question 7

What affects secretion?

Question 8

Treatment for acute diarrhoeal illness?

Answer 8

glucose
salt
water
first two aid in digestion of the second two

Question 9

What are the two parts to digestion?

Answer 9

mechanical
chemical

Question 10

Where is the primary site for digestion and absorption of food?

Answer 10

small intestine

Question 11

Where does digestion occur?

Answer 11

GI lumen by secreted enzymes
Surface of enterocytes by membrane bound enzymes

Question 12

What is paracellular transport?

Question 13

How do enterocytes absorb glucose and galactose?
How is fructose absorbed?

Answer 13

Na - dependent secondary active transport process
fructose is facilitated transport

Question 14

Where does digestion of protein start?

Answer 14

Stomach - pepsin breaks them into polypeptides
In small intestine - short peptides and amino acids

Question 15

Absorption of peptides into intestinal mucosa?

Answer 15

Facilitated diffusion and cotransport

Question 16

How does bile act as an immulsifier?

Question 17

Where are bile slats released and reabsorbed?

Answer 17

released gallbladder and liver
reabsorbed in the ileum, 97% recycled

Question 18

absorption of fats in the small intestine?

Question 19

SEE TABLE

Question 20

What is the role of saliva?

Answer 20

lubricates, cleans oral cavity
- dissolves chemicals
- supresses bacterial growth
- digest starch by amylase

Question 21

Where in the brain controls regulation of saliva secretion?

Answer 21

Salivary center in medulla
(pressure and chemoreceptors in mouth - unconditioned reflex)

Cerebral cortex adjusts for outside inputs (conditioned reflex)

Question 22

see other cool table :)