Insulin synthesis and secretion

Question 1

What happens when food is ingested

Answer 1

there is an increase in glucose

Question 2

What happens when glucose gets above 5nM in the blood in a normal person

Answer 2

Insulin is secreted

Question 3

Glutamate moves across the membrane by facilitated transport when glucose is high in the blood. What helps with this facilitated transport

Answer 3

GLUT2

Question 4

In the cell glucose is changed to what with the help of glucokinase

Answer 4

glucose-6-phosphate

Question 5

Glucose goes through glycolysis, Krebs cycle and electron transport chain to produce how many ATP at the end

Answer 5

net 38 ATP molecules

Question 6

ATP does what to a K channel

Answer 6

closes it to cause increased intracellular K leading to depolarisation of the membrane

Question 7

What does ATP attach to to cause K channels to close

Answer 7

Kir6.2 (only attaches when ATP>ADP)

Question 8

Depolarisation of the membrane causes what

Answer 8

Calcium channels to open causing calcium influx

Question 9

What does Calcium influx do

Answer 9

causes exocytosis of the vesicles that contain insulin

Question 10

Where is insulin made

Answer 10

in the rough endoplasmic reticulum of beta islet cells

Question 11

Can insulin be available immediately

Answer 11

no, insulin is cleaved from preproinsulin (leaves insulin + C peptide) - only 5% of insulin is available immediately

Question 12

What does C peptide do

Answer 12

it has no physiological function

Question 13

Exocrine cells in the pancreas include

Answer 13

acinar cells

Question 14

Endocrine cells in the pancreas include

Answer 14

alpha, beta, sigma and PP cells

Question 15

What do alpha cells secrete in the pancreas

Answer 15

glucagon

Question 16

what do beta cells secrete in the pancreas

Answer 16

insulin

Question 17

what do sigma cells secrete in the pancreas

Answer 17

somatostatin

Question 18

what do PP cells secrete in the pancreas

Answer 18

pancreatic peptide

Question 19

Insulin helps the facilitated transfer of glucose into cells by which transporter

Answer 19

GLUT4

Question 20

What does insulin stimulate

Answer 20

glycogenesis (glucose –> glycogen)

Question 21

What does insulin inhibit

Answer 21

gluconeogenesis, glycogenolysis, lipolysis

Question 22

What does insulin do to fatty acids

Answer 22

encourages its uptake into adipose tissue

Question 23

Which insulin function is disturbed that causes weight loss in people with type 1 diabetes

Answer 23

the inhibition of lipolysis is disturbed

Question 24

What does glucagon do

Answer 24

changes glycogen to glucose in the liver

Question 25

What does adrenaline do

Answer 25

inhibits secretion of insulin and increases synthesis of glucose and stimulates glucagon

Question 26

What does cortisol do

Answer 26

inhibits blood glucose uptake into cells

Question 27

What does growth hormone do

Answer 27

inhibits blood glucose uptake into cells

Question 28

When is cortisol released

Answer 28

in response to stress

Question 29

When ADP>ATP what happens to K channels

Answer 29

They stay open as the ADP-Mg binds to SUR1

Question 30

If the K channel stays open, does insulin get released

Answer 30

no

Question 31

When food is ingested, what 2 peptides are released from the gut

Answer 31

GLP-1 and GIP

Question 32

What does GLP-1 do

Answer 32

increases insulin release, decreases gastric emptying (increases glucose uptake) and decreases glucagon release

Question 33

what does GIP do

Answer 33

Increases insulin release and decreases gastric emptying (increases glucose uptake)

Question 34

Insulin resistance is

Answer 34

the decreased ability to respond to physiological insulin levels - usually linked with obesity