Function of SI

Question 1

How does the SI mechanically digest food?

Answer 1

Peristalsis

Question 2

What does chemical digestion in the SI NOT target? (more than 1)

a) protein
b) fat
c) carbohydrates
d) Neutralisation of gastric acid
e) hormones
f) nucleic acid

Answer 2

e and f

Question 3

What type of cells line the intestine?

Answer 3

Enterocytes

Question 4

The peristalsis in the SI is stronger than in the stomach?

True or false?

Answer 4

False

It is weaker

Question 5

How long does chyme remain in the SI for?

Answer 5

3-5 hours

Question 6

Enteric reflexes respond to the presence of chyme by…?

Answer 6

Increasing intestinal motility

Question 7

What is distension?

Answer 7

Enlargement

Question 8

Distension of the SI causes

a) more vigorous peristalsis
b) weaker peristalsis
c) no change to peristalsis

Answer 8

a

Question 9

How do sympathetic impulses effect intestinal motility?

Answer 9

Decrease

Question 10

Where is pancreatic juice produced?

Answer 10

Acinar cells of pancreas

Question 11

How do pancreatic juices enter the duodenum?

Answer 11

Through the pancreatic duct

Question 12

What does pancreatic juice contain?

Answer 12

Protease, lipases, amylase and sodium bicarbonate

Question 13

What is the function of sodium bicarbonate in the pancreatic juice?

Answer 13

Neutralise chyme

Question 14

What 2 hormones regulate pancreatic juice production?

Answer 14

Hormone cholecystokinin (CCK) and secretin

Question 15

What is the effect of CCK on stomach emptying?

Answer 15

Decreases

Question 16

What is the effect of CCK on bile?

Answer 16

Causing contraction which moves bile into the duodenum

Question 17

What hormone stimulates goblet cells?

Answer 17

VIP

Question 18

What 2 enzymes are found on the apical membrane of enterocytes that digest carbohydrates?

a) peptidases
b) lactase
c) enterokinase
d) sucrose-isomaltase

Answer 18

b and d

Question 19

What is the function of sucrose-isomaltase?

Answer 19

Hydrolyse sucrose

sucrose –> glucose + fructose

Question 20

What is the function of lactase?

Answer 20

Lactose –> glucose + galactose

Question 21

What 2 enzymes are found on the apical membrane of enterocytes that digest proteins?

a) peptidases
b) lactase
c) enterokinase
d) sucrose-isomaltase

Answer 21

a and c

Question 22

What enzyme hydrolyses food proteins in the stomach?

Answer 22

Pepsin

Question 23

What enzyme hydrolyses food protein in the duodenum onwards?

Answer 23

Pancreatic proteases

Question 24

What do peptidases act on?

Answer 24

Mix of small peptides from the hydrolysis of food proteins

Question 25

What do peptidases form?

Answer 25

AA and small peptides

Question 26

Why are the products of peptidases important?

Answer 26

They are small enough to be transported across the apical membrane of the enterocytes

Question 27

What is the function of enterkinase?

Answer 27

Partially hydrolyse pancreatic zymogen proteases to release active enzymes

Question 28

Are there any brush border enzymes that act on lipids or nucleic acids?

Answer 28

No

Question 29

What is the effect of tight junctions around enterocytes on the ECF?

Answer 29

ECF surrounding apical and basolateral membrane are seperated

Question 30

What is the effect of tight junctions around enterocytes on diffusion of proteins?

Answer 30

Prevents

Question 31

What are the consequences fo tight junctions between enterocytes? (3))

Answer 31

Prevent passage of molecules and ions between cells.

To pass through epithelium, materials must enter by diffusion or active transport, this allows regulation and protection