8.1 Function of the Intestines

Question 1

Where is digestion completed?

Answer 1

Enzymes on the brush border that break down carbs and proteins

Question 2

What transporters are on the apical membrane of gut epithelia?

Answer 2

SGLT1 - Co transports galactose/glucose and sodium

GLUT5 - fructose channel

Question 3

What transporters are on the basolateral membrane of gut epithelia?

Answer 3

NaKATPase

GLUT2 - cotransports glucose and fructose

Question 4

In the duodenum what activates the protease zymogens?

Answer 4

Trypsin

Question 5

What minerals are taken up in the intestines?

Answer 5

Calcium

Iron

Question 6

How is vitamin B12 absorbed?

Answer 6

Terminal ileum bound to intrinsic factor

Question 7

What factors cause motility in the small intestine?

Answer 7

Intestinal gradient - drives slow caudal progression
Segmentation - mixes contents
Peristalsis - moves contents

Question 8

What causes motility in the large intestine?

Answer 8

Segmentation (haustral shuttling) - mixes and allows remaining water absorbed
Mass movement - contents rapidly move from the transverse colon to the rectum

Question 9

How does defaecation occur?

Answer 9

Internal sphincter relaxes (parasympathetic)
External sphincter relaxes (somatic)
Intraabdominal pressure rises allowing the expulsion of faeces

Question 10

What is the property of chyme in the intestines?

Answer 10

Isotonic

Neutral