4

Question 1

what does hyperglycaemia cause to macrovasculature

Answer 1

atherosclerosis

Question 2

what does hyperglycaemia cause to microvascuolature

Answer 2

kidney and nerve disease

Question 3

is diabetes communicable

Answer 3

non

Question 4

what causes diabetes

Answer 4

relative insulin deficiency or resistance or both

Question 5

type I diabetes insulin production

Answer 5

very little to none

Question 6

type II diabetes insulin production

Answer 6

muscle sand fat develop insulin resistance and insulin secreting cells don’t produce enough insulin to compensate for it.

Question 7

prevalence in uk of diabetes in 1996

Answer 7

1.4M

in 2035 more than 5M

Question 8

normal blood glucose range

Answer 8

3.5 to 5.5 mmol/L before meals and less than 8 after meals

Question 9

in times of fasting how does the brain get glucose

Answer 9

by breaking down triglycerides.

Question 10

is the pancreas an endocrine or exocrine gland

Answer 10

primarily exocrnine but the islets of langherans of the pancreas form the endocrine part.

Question 11

what do islets of langherans produce

Answer 11

Alpha  (α) cells  producing glucagon​
account for ~30% of human islet cells* ​
	​
Beta (β) cells producing insulin ​
~ 60% of human islet cells* ​

Delta (δ) cells producing somatostatin	​
PP (or γ) cells producing pancreatic ​
polypeptide	​
​
Epsilon (ε) cells producing ghrelin	​

Question 12

whats the structure of insulin

Answer 12

2 chains linked by 3 disulphide linkages

Question 13

whats the effect of zinc on insulin

Answer 13

forms hexamers

Question 14

whats the storage form of insulin

Answer 14

hexamer

Question 15

whats the active form of insulin

Answer 15

monomeric

Question 16

how is the production of insulin controlled

Answer 16

transcription from gene
mrNA stability
mRNA trnaltion
post translational modification

Question 17

whats the ancestor of insulin

Answer 17

preproinsulin in pancreatic b cells
becomes proinsulin in ER
becomes insulin in Golgi after endopeptidase activity which cleave off c peptide from insulin

Question 18

what part of insulin makes it inactive

Answer 18

c peptide

Question 19

what molecule acts as the glucose sensor in the pancreas to release insulin

Answer 19

glucokinase

Question 20

ok now explain how insulin is released

Answer 20

At sub-stimulatory glucose concentrations, KATP channels are open. The resting membrane potential is maintained at a hyperpolarised level (~ −70 mV) ​
​
Increased ATP/ADP ratio results in closure of the KATP channels and membrane depolarisation​
​
Voltage-gated Ca2+ channels open, intracellular concentration of Ca2+ increases and this triggers insulin secretion ​

Question 21

what triggers insulin secretion

Answer 21

CA2plus increase

Question 22

what cells release insulin

Answer 22

pancreatic B cells

Question 23

how do pancreatic B cells release insulin

Answer 23

Pancreatic β cells release insulin in two phases ​
​
The first phase release is rapidly triggered in response to increased blood glucose levels ​
​
The second phase is a sustained, slow release of newly formed vesicles​

Question 24

what kind of receptor is the insulin receptor

Answer 24

tyrosine kinase enzyme linked

Question 25

how are insulin receptors activated

Answer 25

Insulin binds to the α subunits with the receptor.

conformational change activates Tyrosine kinase domain residing on the intracellular portion of the β subunits ​
​
The activated kinase domain autophosphorylates Tyrosine residues on the C-terminus of the receptor itself and phosphorylates Tyrosine residues within the adaptor protein insulin receptor substrate (IRS)​

Question 26

when theres no glucose around, what happens

Answer 26

insulin receptor is not activated
cytoplasm is inactive
GLUT4 are stored intracellular
glucose cannot cross membrane
glucose cannot be converted to glycogen.

Question 27

when glucose concentration increases what happens

Answer 27

insulin is secreted and binds the alpha subunit of tyrosine kinase receptor which phosphyoates its tyrosine residue on its beta subunit
activation of PIP3 leads to GLUT4 being transported to membrane so glucose can come in and can be converted to glycogen.

Question 28

whats the effect of insulin on glucose uptake in muscles and adipocytes

Answer 28

insulin stimulates glucose uptake

Question 29

whats the name of the glucose transporter

Answer 29

GLUT4

Question 30

whats the effect of insulin on glycogen synthesis in muscles

Answer 30

insulin stimulates glycogen synthesis in muscles

Question 31

what allows for activation of glycogen synthase

Answer 31

Akt further down pathywa from insulin phosphory.ates and inactivates glycogen synthase kinase (GSK)

Question 32

in adipocytes what does insulin do to lipogenesis

Answer 32

stimulates and inhibits it.

insulin inhibits HSL so triglycerides cannot be hydrolysed

Question 33

what happens to the liver with insulin

Answer 33

inhibits gluconeogenesis

enhances glucose uptake
increases glycogen synthesis
increases lipogenesis.

Question 34

other functions of insulin

Answer 34

Insulin promotes protein synthesis ​
and storage ​
​
It stimulates transport of aminoacids ​
into the cells​
Valine, leucine, isoleucine, tyrosine, phenylalanine​
​
It increases translation of mRNAs            ​
Synthesis of new proteins​
​
It inhibits catabolism of proteins   ​
It decreases aminoacids release ​
from cells (muscle)​
​
Insulin promotes K+ intracellular uptake​

Question 35

what diabetes does disruption of pancreatic B cells lead to

Answer 35

tupe i