Insulin secretion and signalling

Question 1

which cells does insulin come from

Answer 1

pancreatic B cells

Question 2

where about in the pancreas is insulin secreting cells located?

Answer 2

pancreatic islet

Question 3

what does alpha cells secrete

Answer 3

glucagon

Question 4

what cells produce somatostatin

Answer 4

d cells

Question 5

what do PP cells secrete?

Answer 5

pancreatic polypeptide

Question 6

where is insulin peptide synthesised?

Answer 6

in the rough endoplasmic reticulum of pancreatic b cells

Question 7

is an insulin chain single or poly?

Answer 7

single

Question 8

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

Answer 8

disulphide bridges

Question 9

What transporter does glucose enter b cells through?

Answer 9

GLUT2

Question 10

what phosphorylates glucose?

Answer 10

glucokinase

Question 11

true or false, increased glucose increases intracellular ATP concentration

Answer 11

true

Question 12

true or false, ATP promotes ATP sensitive K+ channels

Answer 12

FALSE- ATP inhibits the K channels

Question 13

what does inhibition of the K ATP channels lead to?

Answer 13

depolarisation of the cell membrane

Question 14

what does depolarisation of the cell membrane lead to?

Answer 14

Ca2+ channel opening

Question 15

What does an increased Ca2+ cause?

Answer 15

fusion of the secretory vesicles and cell membrane to release insulin

Question 16

is release of insulin biphasic or monophasic

Answer 16

BIPHASIC you turd

Question 17

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

Answer 17

SUR1 and Kir6.1

Question 18

why are the two proteins required in the K channels?

Answer 18

provide a functional channel

Question 19

What is K ATP channels regulated by?

Answer 19

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

Question 20

what is MODY?

Answer 20

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

Question 21

How does MODY happen?

Answer 21

genetic defect in B cell function.

Question 22

What is impaired in mody? (used for phosphorylation)

Answer 22

glucokinase

Question 23

What is primarily used to treat MODY

Answer 23

SULPHONYUREA

Question 24

what does genetic screening help you distinguish

Answer 24

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

Question 25

What is typ 1 diabetes

Answer 25

loss of insulin secreting B cells

Question 26

what is type 2 diabetes

Answer 26

defect in insulin sensitivity, hyperglycaemia

Question 27

what is MODY

Answer 27

defect in glucose sensitivity in pancreas/ loss of insulin secretion

Question 28

What is the insulin receptor that insulin binds to?

Answer 28

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

Question 29

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

Answer 29

a negative charge into protein structure

Question 30

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

Answer 30

autophosphorylate- causes a cellular response

Question 31

the transporter protein for insulin regulated glucose transporter is

Answer 31

GLUT4

Question 32

What does insulin promote

Answer 32

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

Question 33

What is leprachaunism

Answer 33

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

Question 34

what abnormalities would be present for leprachaunism

Answer 34

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

Question 35

What is rabson mendenhall syndrome

Answer 35

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

Question 36

What can happen in rabson mendenhall syndrome

Answer 36

acanthosis, fasting hypoglycaemia, diabetic ketoacidosis

Question 37

Where are ketone bodies formed

Answer 37

in liver mitochondria

Question 38

where do ketone bodies come from?

Answer 38

breakdown of fatty acids in acetyl CoA in b oxidation

Question 39

ketone bodies are important in metabolism energy in which organs?

Answer 39

renal contex and heart muscles

Question 40

what state can a build up of ketones lead to?

Answer 40

acidosis

Question 41

what are significant consequences in starvation in diabetics

Answer 41

coma and death due to dehydration

Question 42

Is type 1 or 2 associated with ketoacidosis

Answer 42

type 1