Nutrient Absorption

Question 1

How can water obstruct nutrient absorption?

Answer 1

It forms a layer at the mucosal wall with H-bonds when undisturbed

Question 2

Impediment to nutrient absorption presented by lack of flow in gut

Answer 2

Water forms layer around intestinal wall with H-bonds.

Question 3

Brush-border membrane

Answer 3

Microviliated apical tip of enterocytes in small intestine

Question 4

Which cells secrete mucus in stomach?

Answer 4

Goblet cells

Question 5

Which cells secrete acid in stomach?

Answer 5

Parietal cells

Question 6

Which cells secrete pepsinogen in stomach?

Answer 6

Chief cells

Question 7

Average lifespan of an enterocyte

Answer 7

3-8 days

Question 8

Migration of entreocytes:
1)
2)
3)

Answer 8

1) Stem cells located in crypts
2) Migrate upwards towards vili
3) Differentiate as migrate

Question 9

What do crypt cells secrete?

Answer 9

Water, electrolytes

Question 10

Celiac disease

Answer 10

Gluten causes autoimmune disease

Results in epithelium on villi dying

Question 11

Enzyme that breaks down polysaccharides

Answer 11

Amylase

Question 12

Macromolecule broken down by amylase

Answer 12

Polysaccharides

Question 13

Environment in which amylase works the best

Answer 13

Neutral pH

Question 14

Efficiency of amylase in mouth

Answer 14

Poor

Food not broken down enough for amylase to access much surface area

Question 15

Method of digestion in stomach

Answer 15

Peristalsis grinds food against pylorus to break it down

Question 16

Where does amylase become effective?

Answer 16

In the duodenum

Bicarbonate neutralises acid

Question 17

Hormones released when food enters duodenum

Answer 17

Secretin

Cholecystokinin

Question 18

Role of secretin

Answer 18

Activates water secretion
Activates bicarbonate secretion
Inhibits stomach emptying

Question 19

Action of secretion

Answer 19

Enters blood, stimulates pancreas

Question 20

Cholecystokinin role

Answer 20

Stimulates pancreatic amylase release into duodenum

Question 21

Types of absorbable sugars

Answer 21

Glucrose, galactose, fructose

Question 22

Maltose

Answer 22

2xGlucose

Question 23

Sucrose

Answer 23

Glucose+Fructose

Question 24

Lactose

Answer 24

Glucose+Galactose

Question 25

How do glucose and galactose cross apical membrane?

Answer 25

Sodium-glucose linked transporter (SGLT)

Question 26

What powers the sodium-glucose linked transporter?

Answer 26

Sodium gradient across endothelial wall

Question 27

What converts pepsinogen to pepsin?

Answer 27

Low pH

Question 28

Endopeptidase

Answer 28

Breaks bonds within a polypeptide chain

Question 29

Limit of endopeptidases

Answer 29

Can't produce individual amino acids

Question 30

Where does fat sit in the stomach?

Answer 30

On top of carbs and proteins

Question 31

Which pancreatic proteases are released upon cholecystokinin signalling?

Answer 31

Trypsin, chymotrypsin

Question 32

Factors released upon cholecystokinin signalling

Answer 32

Pancreatic proteases

Question 33

Exopeptidases

Answer 33

Remove amino acids from the ends of proteins

Question 34

Types of exopeptidases

Answer 34

Carboxypeptidases | Aminopeptidases

Question 35

How are pancreatic proteases secreted?

Answer 35

As proenzymes

Question 36

How is protrypsin converted to trypsin?

Answer 36

Enteropeptidase in the brush-border membrane

Question 37

Enzyme activated by enteropeptidase in the brush-border membrane

Answer 37

Protrypsin --> trypsin

Question 38

Which enzymes are activated by trypsin?

Answer 38

Chymotrypsinogen --> Chymotrypsin | Procarboxypeptidase --> Carboxypeptidase

Question 39

What converts chymotrypsinogen to chymotrypsin?

Answer 39

Trypsin

Question 40

What converts procarboxypeptidase to carboxypeptidase?

Answer 40

Trypsin

Question 41

Which factor stimulates trypsin release?

Answer 41

Cholecystokinin

Question 42

What is the pathway for secreted chymotrypsin?

Answer 42

Cholecystokinin --> Protrypsin --> Trypsin --> Chymotrypsinogen --> Chymotrypsin

Question 43

Types of exopeptidases in the brush-border membrane

Answer 43

Aminopeptidases

Question 44

Where are fats mostly broken down?

Answer 44

Duodenum

Question 45

Which fat can stimulate CCK release?

Answer 45

Free fatty acids

Question 46

An effect of CCK release

Answer 46

Feel sated, release bile (for fat digestion)

Question 47

Effect of bile on fats

Answer 47

Emulsification