absorption and secretion

Question 1

how are amino acids absorbed

Answer 1

sodium dependant co transport in the small intestine

Question 2

how are dipetides absorbed

Answer 2

H+ dipeptide cotransport

Question 3

how are tripeptides absorbed

Answer 3

H+ tripeptide cotransport

Question 4

what is the role of gastric lipase

Answer 4

slow the rate of gastric emptying

hydrolyse triglycerides

Question 5

what are chylomicrons made of

Answer 5

core of triglycerides and cholesterol ester

phospholipids and apolipoproteins on the outside

Question 6

where do the chylomicrons go next

Answer 6

packaged into secretory vesicles on the Golgi membrane and exocytosed across the basolateral membrane

then enter the lacteals

Question 7

describe the tight junctions in the intestine

Answer 7

small intestine- leaky

colon- impermeable so no paracellular route for fluids and electrolytes

Question 8

what are crypts of Lieberkuhn for

Answer 8

secretion

Question 9

what are colonic glands for

Answer 9

secretion

Question 10

where is the zone of cell proliferation

Answer 10

base of the crypts, replaces the villous cells

Question 11

what is a secretagog

Answer 11

a substance that promotes secretion

Question 12

describe the absorption of lipids

Answer 12

Bile salts form micelles
Diffusion of products into intestinal cells
Re-esterification within the cell to
triglycerides and cholesterol
Chylomicrons form in the cell and transfer to
lymph

Question 13

how is bile absorbed

Answer 13

sodium dependant co transport

Question 14

how is iron absorbed

Answer 14

binds to apoferritin in the intestinal cell and transferrin in the blood

Question 15

how is calcium absorbed

Answer 15

vitamin D dependant Ca+ binding protein- Calbindin

Question 16

how are water soluble vitamins absorbed

Answer 16

na dependant cotransport

Question 17

how is glucose and galactose absorbed

Answer 17

Na dependant co transport in the small intestine via SGLT1

Question 18

how is fructose absorbed

Answer 18

facilitated diffusion Via glucose transporter 5, GLUT5

Question 19

how are monosaccharides absorbed into the blood

Answer 19

GLUT2

Question 20

name the pancreatic proteases which are secreted as inactive precursors into the small intestine

Answer 20

trypsinogen
chemotrypsinogen
proelastase
procarboxypeptidase A and B

Question 21

how is trypsinogen converted to trypsin

Answer 21

brush border enzyme enterokinase

trypsin then converts the others

Question 22

how is pepsinogen converted to pepsin

Answer 22

low pH

Question 23

what happens to dipeptides and tripeptides in the small intestine epithelia

Answer 23

they are broken down into amino acids

Question 24

where are lipases found

Answer 24

tongue, stomach and small intestine

Question 25

where is cholecystokinin released

Answer 25

i cells of the duodenum and jejunum in response to monoglycerides and peptides and fatty acids

Question 26

what is lysolecithin

Answer 26

emulsifies lipids

Question 27

what enzymes are involved in fat digestion

Answer 27

pancreatic lipase, cholesterol ester hydrolase, phospolipase A and colipase

Question 28

where are fatty acids and monoglycerides stored before absorption

Answer 28

micelles

Question 29

what are chylomicrons made of

Answer 29

fats, cholesterol and proteins

made in the intestinal cells, then to lacteals

Question 30

where are chylomicrons processed

Answer 30

golgi

Question 31

what is the function of cAMP in the small intestine

Answer 31

increased anion secretion

inhibited NaCl absorption

Question 32

what is the second messenger of VIP

Answer 32

cAMP