Function of SI Flashcards

1
Q

How does the SI mechanically digest food?

A

Peristalsis

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2
Q

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

A

e and f

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3
Q

What type of cells line the intestine?

A

Enterocytes

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4
Q

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

True or false?

A

False

It is weaker

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5
Q

How long does chyme remain in the SI for?

A

3-5 hours

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6
Q

Enteric reflexes respond to the presence of chyme by…?

A

Increasing intestinal motility

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7
Q

What is distension?

A

Enlargement

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8
Q

Distension of the SI causes

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

A

a

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9
Q

How do sympathetic impulses effect intestinal motility?

A

Decrease

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10
Q

Where is pancreatic juice produced?

A

Acinar cells of pancreas

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11
Q

How do pancreatic juices enter the duodenum?

A

Through the pancreatic duct

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12
Q

What does pancreatic juice contain?

A

Protease, lipases, amylase and sodium bicarbonate

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13
Q

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

A

Neutralise chyme

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14
Q

What 2 hormones regulate pancreatic juice production?

A

Hormone cholecystokinin (CCK) and secretin

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15
Q

What is the effect of CCK on stomach emptying?

A

Decreases

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16
Q

What is the effect of CCK on bile?

A

Causing contraction which moves bile into the duodenum

17
Q

What hormone stimulates goblet cells?

18
Q

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

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

19
Q

What is the function of sucrose-isomaltase?

A

Hydrolyse sucrose

sucrose –> glucose + fructose

20
Q

What is the function of lactase?

A

Lactose –> glucose + galactose

21
Q

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

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

22
Q

What enzyme hydrolyses food proteins in the stomach?

23
Q

What enzyme hydrolyses food protein in the duodenum onwards?

A

Pancreatic proteases

24
Q

What do peptidases act on?

A

Mix of small peptides from the hydrolysis of food proteins

25
What do peptidases form?
AA and small peptides
26
Why are the products of peptidases important?
They are small enough to be transported across the apical membrane of the enterocytes
27
What is the function of enterkinase?
Partially hydrolyse pancreatic zymogen proteases to release active enzymes
28
Are there any brush border enzymes that act on lipids or nucleic acids?
No
29
What is the effect of tight junctions around enterocytes on the ECF?
ECF surrounding apical and basolateral membrane are seperated
30
What is the effect of tight junctions around enterocytes on diffusion of proteins?
Prevents
31
What are the consequences fo tight junctions between enterocytes? (3))
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