8.1 The Intestines

Question 1

What are the folds in the intestines called?

Answer 1

Plicae circulares

Question 2

Why do contents move slowly through the intestines?

Answer 2

To allow maximal time for absorption

Question 3

What are the epithelial cells which line the intestines called?

Answer 3

Enterocytes

Question 4

What do goblet cells secrete?

Answer 4

Mucous

Question 5

What is the cell death of intestinal enterocytes called?

Answer 5

Anoikis

Question 6

What are the final products of carbohydrate digestion?

Answer 6

Monosaccharides

Question 7

What are the three most common monosaccharides?

Answer 7

Glucose, galactose and fructose

Question 8

What enzyme breaks up starch?

Answer 8

Amylase

Question 9

What transporter do glucose and galactose move through on the apical membrane of enterocytes?

Answer 9

SGLT-1

Question 10

What transporter does fructose move through on the apical membrane of enterocytes?

Answer 10

GLUT-5

Question 11

What is driving the absorption of monosaccharides?

Answer 11

Na-K-ATPase

Question 12

What transporter do all sugars move through on the basolateral membrane of the enterocytes?

Answer 12

GLUT-2

Question 13

Describe the basis of oral rehydration therapy

Answer 13

Na+, glucose and water are given to dehydrated patients to stimulate maximal water absorption in the intestines

Question 14

How are proteins broken down by the intestines?

Answer 14

The proteins must be broken down into tripeptides, dipeptides or individual amino acids by peptin and other proteases.

Question 15

How are tripeptides and dipeptides absorbed by the intestines?

Answer 15

Via a H+ co-transporter

Question 16

How are amino acids absorbed by the intestines?

Answer 16

Via a Na+ co-transporter

Question 17

What are Na+ channels in the intestine stimulated by?

Answer 17

Aldosterone

Question 18

How is Calcium absorbed by the intestines?

Answer 18

Enters enterocytes via facilitated diffusion and exits via Ca2+ ATPase. The process requires vitamin D

Question 19

How is Iron absorbed by the body?

Answer 19

Fe2+ is absorbed across the apical membrane passively. It binds to apoferritin and then moves across the basolateral membrane

Question 20

Where is vitamin B12 absorbed?

Answer 20

Terminal ileum

Question 21

What is segmentaion of the intestines?

Answer 21

Movement of the food back and forth in the intestine

Question 22

What is peristalsis?

Answer 22

Co-ordinated contractions that move the contents distally

Question 23

What is mass movement?

Answer 23

Moves contents rapidly towards the rectum

Question 24

What control is the internal anal sphincter under?

Answer 24

Parasympathetic control

Question 25

What control is the external anal sphincter under?

Answer 25

Voluntary (somatic)