Drive - absorption

Question 1

By what process is K+ reabsorbed?

Answer 1

Passive diffusion

Question 2

By what process is Cl- reabsorbed?

Answer 2

Active transport (in exchange for bicarbonate)

Question 3

What does absorptive state mean/entail?

Answer 3

During which ingested nutrients enter the blood (from the GI tract)
Some provide immediate energy remainder is added to body’s energy stores

Question 4

What does the postabsorptive state mean/entail?

Answer 4

During which the GI tracts is empty of nutrients and the body’s on stores must supply energy

Question 5

What is the main enzyme involved in the digestion of lipids ad where is this synthesised?

Answer 5

Lipase - synthesised in the pancreas

Question 6

What does lipase do?

Answer 6

Hydrolyses the ester bonds on carbon 1 and 3 of triglycerides to produce a monoglyceride and 2 fatty acids

Question 7

What are micelles

Answer 7

Small droplets of fat, bile salts, cholesterol and fat soluble vitamins. Acts as a “holding station” for lipids.

Question 8

What are the 4 (main?) fat soluble vitamins?

Answer 8

A, D, E, K

Question 9

What are chylomicrons?

Answer 9

Vesicles that contain triglycerides, phospholipids, cholesterol and fat soluble vitamins

Question 10

Where are chylomicrons found and where do they go?

Answer 10

Golgi apparatus > vesicles form an travel to membrane where they fuse > pass into the interstitial fluid > enter the lacteals

Question 11

What are lacteals?

Answer 11

Lymphatic vessels in the intestinal villi

Question 12

Which vitamins are absorbed in the ilium?

Answer 12

The fat soluble ones = A, D, E and K

Question 13

Which vitamins are absorbed in the jejunum?

Answer 13

The water soluble ones = vitamin B and C

except B12

Question 14

Where is B12 absorbed?

Answer 14

In the terminal ileum

Question 15

How many amino acids are essential (and why are they essential)?

Answer 15

8 - as we cannot manufacture them ourselves

Question 16

Which isomer form of amino acids can we utilise?

Answer 16

L-form (optic isomer)

Question 17

Where does protein digestion begin?

Answer 17

In the stomach by pepsin (an endopeptidase)

Question 18

Where is pepsinogen 1 located?

Answer 18

Only in the HCl secreting region of the stomach (mainly the body)

Question 19

Where is pepsinogen 2 located?

Answer 19

Found in the pyloric region

Question 20

What is the optimal pH for pepsin?

Answer 20

pH = 1.6 to 3.2

Question 21

What is the pH is the majority of the duodenum?

Answer 21

pH = 6.5

Question 22

What form of the sugars are utilised in metabolism

Answer 22

D-isomers (optical isomerism)

Question 23

Which has more branching glycogen or starch?

Answer 23

Glycogen

Question 24

Where are oligosacchridases located?

Answer 24

At the outer portion of the membrane of the microvilli

Question 25

What carrier is involved in the process of absorption of glucose?

Answer 25

Sodium-glucose-cotransporter (SGLT)

Question 26

What carrier is involved in the process of absorption of galactose?

Answer 26

Sodium-glucose-cotransporter (SGLT)

Question 27

What carrier is involved in the process of absorption of fructose?

Answer 27

GLUT transporter

Question 28

What % of the small intestine are the majority of carbohydrates digested and absorbed

Answer 28

first 20%

Question 29

Which part of the small intestine reabsorbs the most water?

Answer 29

Jejunum

Question 30

What type of absorption does Na+ pass into the cell membranes via?

Answer 30

Active transport

Question 31

List 5 key features of the jejunum:

Answer 31

No Peyer’s patches

Long narrow villi

Lots of goblet cells

Closely packed plica circularis

Lymph node at lamina propria

Question 32

List 4 key features of the ileum:

Answer 32

Large Peyer’s patches

Shorter villi

Goblet cells increase towards distal end

Fewer plicae circularis