L3 - Endocrine pancreas (L4.1)

Question 1

name of the group of cells in the pancreas

Answer 1

islets of langerhans

Question 2

4 types of cells part of the islets of langerhans

Answer 2

1. alpha
2. beta
3. delta
4. PP cells

Question 3

what do alpha cells secrete?

Answer 3

glucagon

Question 4

what do beta cells secrete?

Answer 4

insulin + amylin

Question 5

what do delta cells secrete?

Answer 5

somatostatin

Question 6

what do PP cells secrete?

Answer 6

pancreatic polypeptide

Question 7

describe the structure of insulin

Answer 7

2 AA chains (1 x alpha and 1 x beta)
linked by 2 di-sulphide bonds
intrasubunit disulphide bond in A chain

Question 8

describe steps of insulin synthesis

Answer 8

1. pre-proinsulin produced by ER
2. transported to GA
3. pre-proinsulin cleaved into proinsulin
4. proinsulin cleaved into insulin + c-peptide

Question 9

what substance is an indicator for the prescence of insulin? why?

Answer 9

c-peptide; as it is produced with insulin

Question 10

what 3 things control insulin secretion?

Answer 10

1. blood glucose
2. neural stimulation
3. hormones

Question 11

why is glucose more effect orally than IV?

Answer 11

glucose in the GI tract is digested - GI hormones such as incretins can stimulate b cells to secrete insulin

Question 12

4 stimulaters of insulin secretion

Answer 12

1. parasymapthetic NS
2. glucagon
3. blood glucose
4. GI incretins; GIP and GLP-1

Question 13

2 inhibitors of insulin secretion

Answer 13

1. somatostain

2. sympathetic NS

Question 14

which vessel is insulin released into? which organ does this go to?

Answer 14

portal vein - liver

Question 15

why is it better to use c-protein as an indictor for insulin rather than insulin?

Answer 15

c-protein has a much longer half life

Question 16

how is insulin broken down?

Answer 16

proteolytic degradation

Question 17

where is insulin broken down?

Answer 17

liver, kidney and muscle

Question 18

is insulin the only hormone to reduce BG?

Answer 18

yes

Question 19

2 long term effects of insulin

Answer 19

1. increase/decrease key enzymes

2. stimulate cell proliferation

Question 20

4 effects of insulin in the liver

Answer 20

1. increased glycogenesis
2. increased glycolysis
3. increased lipogenesis
4. decreased ketosis and synthesis of ketone bodies

Question 21

4 effects of insulin in fat

Answer 21

1. increased glucose uptake
2. increased fatty acid uptake
3. increased fat synthesis
4. increased glycolysis

Question 22

4 effects of insulin in muscle

Answer 22

1. increased glycogenesis
2. increased glycolysis
3. increased glucose uptake
4. increased uptake of AA

Question 23

what effect does insulin have on the synthesis of ketones?

Answer 23

decrease

Question 24

what occurs when the level of ketone bodies increase?

Answer 24

ketone acidosis occurs - turns blood acidic

Question 25

what causes ketoacidosis?

Answer 25

when only fat is broken down to form glucose - as lack of carbs

Question 26

how is glucose transported into the cell?

Answer 26

GLUT transporter

Question 27

what are GLUT tranporters dependent on?

Answer 27

insulin

Question 28

function of glucagon

Answer 28

increase blood glucose

Question 29

4 things which glucagon is stimulated by

Answer 29

1. AA in plasma 2. low conc of glucose + fatty acids 3. catecholamines (Ne+E) 4. cholinergic stimuli

Question 30

2 things which glucagon is inhibitated by

Answer 30

1. somatostatin | 2. high conc of glucose + fatty acids

Question 31

4 effects of glucagon on carbs

Answer 31

1. increase gluconeogenesis 2. increase glycolysis 3. decrease glycogen synthesis 4. dec glucose oxidation

Question 32

3 effects of glucagon on lipids

Answer 32

1. increase lipolysis 2. increase ketogeneiss 3. dec lipogenesis

Question 33

1 effect of glucagon on protein

Answer 33

1. increase proteolyis

Question 34

in gluconeogensis, what is new glucose produced from?

Answer 34

proteins, AA, glycerol

Question 35

when does gluconeogenesis occur?

Answer 35

when there is a limited glucose supply

Question 36

where is amylin released from?

Answer 36

beta cells

Question 37

which hormone does amylin complement?

Answer 37

insulin

Question 38

how does amylin complement the effects of insulin? (3)

Answer 38

1. reduce gastric emptying 2. antagonising glucagon effects 3. reducing food intake

Question 39

name of amylin drug

Answer 39

pramlintide

Question 40

function of somatostatin?

Answer 40

imhibit insulin and glucagon release | inhibit release of GI hormones = gastrin, motilin, VIP

Question 41

a major portion of islets of langerhans consist of what type of cell?

Answer 41

beta

Question 42

main action of insulin

Answer 42

lower BG

Question 43

half-life of insulin

Answer 43

3-5 mins

Question 44

main target tissue for glucagon?

Answer 44

liver

Question 45

3 main target tissues for insulin?

Answer 45

liver muscles fat

Question 46

name of process: oxidation of glucose to produce energy

Answer 46

glycolysis

Question 47

name of process:synthesis of glucose from non-carb

Answer 47

gluconeogenesis

Question 48

name of process: synthesis of glycogen from glucose

Answer 48

glycogenesis

Question 49

name of process: breakdown of glycogen to form glucose

Answer 49

glycogenolysis

Question 50

main function of glucagon

Answer 50

increase BG

Question 51

T/F: insulin promotes glycogenesis

Answer 51

true

Question 52

T/F: insulin promotes glucose uptake into cells

Answer 52

true

Question 53

T/F: insulin inhibits ketosis

Answer 53

true

Question 54

T/F: glucagon promotes gluconeogenesis

Answer 54

true

Question 55

T/F: insulin inhibits glycogenolysis

Answer 55

true

Question 56

T/F: insulin inhibits glycolysis

Answer 56

false

Question 57

T/F: glucagon stimulates glycogenesis

Answer 57

false

Question 58

what do incretins stimulate?

Answer 58

insulin release from beta cells