Insulin secretion and signalling Flashcards Preview

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Flashcards in Insulin secretion and signalling Deck (42):
1

which cells does insulin come from

pancreatic B cells

2

where about in the pancreas is insulin secreting cells located?

pancreatic islet

3

what does alpha cells secrete

glucagon

4

what cells produce somatostatin

d cells

5

what do PP cells secrete?

pancreatic polypeptide

6

where is insulin peptide synthesised?

in the rough endoplasmic reticulum of pancreatic b cells

7

is an insulin chain single or poly?

single

8

what links two polypeptide chains together in a polypeptide insulin chain ?

disulphide bridges

9

What transporter does glucose enter b cells through?

GLUT2

10

what phosphorylates glucose?

glucokinase

11

true or false, increased glucose increases intracellular ATP concentration

true

12

true or false, ATP promotes ATP sensitive K+ channels

FALSE- ATP inhibits the K channels

13

what does inhibition of the K ATP channels lead to?

depolarisation of the cell membrane

14

what does depolarisation of the cell membrane lead to?

Ca2+ channel opening

15

What does an increased Ca2+ cause?

fusion of the secretory vesicles and cell membrane to release insulin

16

is release of insulin biphasic or monophasic

BIPHASIC you turd

17

what are the two proteins that make up K ATP channels?

SUR1 and Kir6.1

18

why are the two proteins required in the K channels?

provide a functional channel

19

What is K ATP channels regulated by?

sulphonylurea and ATP- inhibts channels to promote depolarisation. DIAZOXIDE stimulates K ATP channels thus inhibits insulin secretion.

20

what is MODY?

maturity onset diabetes of the young- early onset type 2 diabetes- defect in insulin secretion.

21

How does MODY happen?

genetic defect in B cell function.

22

What is impaired in mody? (used for phosphorylation)

glucokinase

23

What is primarily used to treat MODY

SULPHONYUREA

24

what does genetic screening help you distinguish

type 1 and MODY- type 1= insulin, MODY= sulphonyurea

25

What is typ 1 diabetes

loss of insulin secreting B cells

26

what is type 2 diabetes

defect in insulin sensitivity, hyperglycaemia

27

what is MODY

defect in glucose sensitivity in pancreas/ loss of insulin secretion

28

What is the insulin receptor that insulin binds to?

DIMERIC tyrosine kinase (2 alpha- extracellular and 2 beta cytoplasmic)

29

by proteins phosphorylating on any hydroxyl group this gives...

a negative charge into protein structure

30

When alpha subunits are bound to insulin, what does this cause the beta cells to do?

autophosphorylate- causes a cellular response

31

the transporter protein for insulin regulated glucose transporter is

GLUT4

32

What does insulin promote

DNA synthesis, protein synthesis, gene expression, growth, glucose uptake in muscle and adipose tissues, amino acid uptake, glycogen synthesis, lipolysis

33

What is leprachaunism

rare autosomal recessive genetic trait where there is a mutation in the gene for insulin receptor binding/ signalling

34

what abnormalities would be present for leprachaunism

growth retardation, black hair, short stature, absence of fat

35

What is rabson mendenhall syndrome

rare autosomal recessive genetic trait- SEVERE insulin resistance, hyperglycaemia, hyperinsulinaemia.

36

What can happen in rabson mendenhall syndrome

acanthosis, fasting hypoglycaemia, diabetic ketoacidosis

37

Where are ketone bodies formed

in liver mitochondria

38

where do ketone bodies come from?

breakdown of fatty acids in acetyl CoA in b oxidation

39

ketone bodies are important in metabolism energy in which organs?

renal contex and heart muscles

40

what state can a build up of ketones lead to?

acidosis

41

what are significant consequences in starvation in diabetics

coma and death due to dehydration

42

Is type 1 or 2 associated with ketoacidosis

type 1