Lecture 12

Question 1

By the ileum, what percentage of nutrients and electrolytes have been absorbed?

Answer 1

100% nutrients, 90% electrolytes

Question 2

Does the large intestine have villi?

Answer 2

No, just crypts

Question 3

What are colon cells called?

Answer 3

Colonocytes

Question 4

What cells secrete mucus in the large intestine?

Answer 4

Goblet cells

Question 5

What is longitudinal muscle called in the large intestine?

Answer 5

Tainae coli

Question 6

What is the mixing movement in the large intestine called?

Answer 6

Haustration

Question 7

What is actively absorbed in the large intestine?

Answer 7

Na+

Question 8

What is actively secreted in the large intestine?

Answer 8

K+

Question 9

Which provides more water, Na+ and Cl- into the GI tract? diet or secretions?

Answer 9

secretions

Question 10

Is the material reaching the small intestine hypertonic or hypotonic?

Answer 10

Hypertonic- this would promote water secretion/loss.

Question 11

What is the primary mechanism for Na+ absorption?

Answer 11

Co transport with glucose via SGLT1 or with neutral amino acids via Boat1

Question 12

What transporter exchanges Na+ for H+?

Answer 12

NHE3

Question 13

What inhibits NHE3?

Answer 13

Amiloride

Question 14

Between meals, what is the most important mechanism for fluid and salt absorption?

Answer 14

Na+/H+ and Cl-/HCO3- parallel exchangers. DRA and NHE3

Question 15

What is the epithelial Na+ channel?

Answer 15

ENaC

Question 16

What increases the action of ENaC?

Answer 16

Aldosterone

Question 17

What transporter is present in crypt cells BLM for chloride secretion?

Answer 17

NKCC1

Question 18

What is the apical Cl- transporter?

Answer 18

CFTR

Question 19

What is congenital chloride diarrhoea?

Answer 19

Cl-/HCO3- DRA dysfunction, so Cl- is not absorbed, also get metabolic alkalosis.

Question 20

2 examples of osmotic diarrhoea:

Answer 20

Lactase deficiency and glucose-galactose malabsorption