Glucose homeostasis

Question 1

Why is glucose importnat

Answer 1

Energy substrate

Important in CNS

Can lead to unconsciousness, coma and death

Question 2

What are the normal levels of glucose concentration

Answer 2

4-5 mmol/L

Question 3

What hormones help to increase blood glucose

Answer 3

Glucagon

Cortisol

GH

Catecholamines

Question 4

Why is it a challenge for people living with diabetes in terms of hormones

Answer 4

Only insulin which can lead to hypoglycaemia

Question 5

Which diabetes type is the most prevalent

Answer 5

Type 2

Type 1

Last maturity onset diabetes of the young

Question 6

Anatomy of the pancreas

Answer 6

It is a retroperitonael structure

Question 7

How much is the pacrease is made out of exocrine secretions

Answer 7

98%

Question 8

What are the different type of islet of langerhans

Answer 8

Question 9

What are pancreatic polypeptide producing cells

Answer 9

Communicate between gap junctions and tight junctions

Paracrine communications between islet cells

Question 10

What does somatostatin do in terms of pancreatic hormones

Answer 10

Keep both of the hormones in balance

Negative feedback hormone

Question 11

What other function does insulin have apart from lowering blood glucose

Answer 11

imporatn in fetal growth and development

Question 12

Reactions to an increase in blood glucose

Answer 12

Question 13

How does insulin regulate glucose

Answer 13

Build up of glycogen stores - glycognesis

Breakdown of glucose - glycolysis

Increase uptake of glucose to cell - mediated by GLUT4 (predominantely in skeletal muscles and adipocytes)

Amino acids transport increases - increase in protein synthesis

Increase in lipogenesi s- decrease in lipolysis

Question 14

Reaction to reduction in blood glucose

Answer 14

Question 15

Reaction to reduction in blood glucose

Answer 15

Increase lipolysis

Increase gluconeogenesis

Increase hepatic glycogenolysis

Increase amino acid transport into liver

Question 16

Glucokinase

Answer 16

GLUT-2 is not insulin sensitive

High affinity for glucose, whenver glucose in bloodstream reflected in B cell

Glucose is converted by glucokinase (hexokinase IV), not subject to negative feedback

Glucose - 6 - phosphate gives a good idea of how much glucose

High ATP produced which closes K+ channels

Membrane depolarisation which opens calcium channel gates

Calcium influx promotes insulin release

Question 17

How are insulin and C-peptide related

Answer 17

Insulin is stored in proinsulin

Undergoes proteolytic cleavage

Breakdown protein C peptide gives better indication of how much insulin someone is producing as insulin is relatively unstable

Question 18

What is the incretin effect

Answer 18

Gut hormones inhance insulin secretion and reduction in glucagon

GLP - 1 (glucagon like peptide)

Rpaidly degraded

Secreted in response to nutrients in the gut

Increasing levels of satiety

Treatment for diabetes

Question 19

First phase Insulin Reponse

Answer 19

Respones gets blunted

Beta cells work too much and cannot produce load

Question 20

Picture of insulin receptor

Answer 20

Insulin binds to extracellular part

Induces a conformational change in the tyrosine kinase domain of B subunit