L3 - Endocrine pancreas (L4.1) Flashcards

1
Q

name of the group of cells in the pancreas

A

islets of langerhans

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2
Q

4 types of cells part of the islets of langerhans

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

what do alpha cells secrete?

A

glucagon

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4
Q

what do beta cells secrete?

A

insulin + amylin

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5
Q

what do delta cells secrete?

A

somatostatin

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6
Q

what do PP cells secrete?

A

pancreatic polypeptide

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7
Q

describe the structure of insulin

A

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

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8
Q

describe steps of insulin synthesis

A
  1. pre-proinsulin produced by ER
  2. transported to GA
  3. pre-proinsulin cleaved into proinsulin
  4. proinsulin cleaved into insulin + c-peptide
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9
Q

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

A

c-peptide; as it is produced with insulin

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10
Q

what 3 things control insulin secretion?

A
  1. blood glucose
  2. neural stimulation
  3. hormones
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11
Q

why is glucose more effect orally than IV?

A

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

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12
Q

4 stimulaters of insulin secretion

A
  1. parasymapthetic NS
  2. glucagon
  3. blood glucose
  4. GI incretins; GIP and GLP-1
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13
Q

2 inhibitors of insulin secretion

A
  1. somatostain

2. sympathetic NS

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14
Q

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

A

portal vein - liver

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15
Q

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

A

c-protein has a much longer half life

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16
Q

how is insulin broken down?

A

proteolytic degradation

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17
Q

where is insulin broken down?

A

liver, kidney and muscle

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18
Q

is insulin the only hormone to reduce BG?

A

yes

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19
Q

2 long term effects of insulin

A
  1. increase/decrease key enzymes

2. stimulate cell proliferation

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20
Q

4 effects of insulin in the liver

A
  1. increased glycogenesis
  2. increased glycolysis
  3. increased lipogenesis
  4. decreased ketosis and synthesis of ketone bodies
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21
Q

4 effects of insulin in fat

A
  1. increased glucose uptake
  2. increased fatty acid uptake
  3. increased fat synthesis
  4. increased glycolysis
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22
Q

4 effects of insulin in muscle

A
  1. increased glycogenesis
  2. increased glycolysis
  3. increased glucose uptake
  4. increased uptake of AA
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23
Q

what effect does insulin have on the synthesis of ketones?

A

decrease

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24
Q

what occurs when the level of ketone bodies increase?

A

ketone acidosis occurs - turns blood acidic

25
Q

what causes ketoacidosis?

A

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

26
Q

how is glucose transported into the cell?

A

GLUT transporter

27
Q

what are GLUT tranporters dependent on?

A

insulin

28
Q

function of glucagon

A

increase blood glucose

29
Q

4 things which glucagon is stimulated by

A
  1. AA in plasma
  2. low conc of glucose + fatty acids
  3. catecholamines (Ne+E)
  4. cholinergic stimuli
30
Q

2 things which glucagon is inhibitated by

A
  1. somatostatin

2. high conc of glucose + fatty acids

31
Q

4 effects of glucagon on carbs

A
  1. increase gluconeogenesis
  2. increase glycolysis
  3. decrease glycogen synthesis
  4. dec glucose oxidation
32
Q

3 effects of glucagon on lipids

A
  1. increase lipolysis
  2. increase ketogeneiss
  3. dec lipogenesis
33
Q

1 effect of glucagon on protein

A
  1. increase proteolyis
34
Q

in gluconeogensis, what is new glucose produced from?

A

proteins, AA, glycerol

35
Q

when does gluconeogenesis occur?

A

when there is a limited glucose supply

36
Q

where is amylin released from?

A

beta cells

37
Q

which hormone does amylin complement?

A

insulin

38
Q

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

A
  1. reduce gastric emptying
  2. antagonising glucagon effects
  3. reducing food intake
39
Q

name of amylin drug

A

pramlintide

40
Q

function of somatostatin?

A

imhibit insulin and glucagon release

inhibit release of GI hormones = gastrin, motilin, VIP

41
Q

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

A

beta

42
Q

main action of insulin

A

lower BG

43
Q

half-life of insulin

A

3-5 mins

44
Q

main target tissue for glucagon?

A

liver

45
Q

3 main target tissues for insulin?

A

liver
muscles
fat

46
Q

name of process: oxidation of glucose to produce energy

A

glycolysis

47
Q

name of process:synthesis of glucose from non-carb

A

gluconeogenesis

48
Q

name of process: synthesis of glycogen from glucose

A

glycogenesis

49
Q

name of process: breakdown of glycogen to form glucose

A

glycogenolysis

50
Q

main function of glucagon

A

increase BG

51
Q

T/F: insulin promotes glycogenesis

A

true

52
Q

T/F: insulin promotes glucose uptake into cells

A

true

53
Q

T/F: insulin inhibits ketosis

A

true

54
Q

T/F: glucagon promotes gluconeogenesis

A

true

55
Q

T/F: insulin inhibits glycogenolysis

A

true

56
Q

T/F: insulin inhibits glycolysis

A

false

57
Q

T/F: glucagon stimulates glycogenesis

A

false

58
Q

what do incretins stimulate?

A

insulin release from beta cells