Carbohydrate metabolism and control of blood glucose

Question 1

how is glucose transported across the cell membrane

Answer 1

facilitated diffusion
glucose binds to the receptor carrier protien
creates a conformational change
intracellular release

Question 2

how is GI glucose absorption brought about

Answer 2

linked to active sodium -glucose co- transport

Question 3

Where is insulin produced

Answer 3

Pancreatic beta cells in the islets of langerhans

Question 4

When is insulin secreted

Answer 4

When blood sugars are high

Question 5

What is the half life of insulin

Answer 5

6 mins

Question 6

How is insulin degraded

Answer 6

by insulinase in the liver

Question 7

What is the mechanism of insulin secretion

Answer 7

-increase in glucose - glucsose taken into beta-cell by faciliated diffusion
- glucose converted to glucose-6-phophate by glucokinase
G6P oxidised to ATP
k+ channels open and K+ enter cell- depolarises
Depolarisation causes Ca2+ channel to open and influx of Ca2+
Insulin stored in vesicles exit the cell by exocytosis

Question 8

impact of somatostatin/norepinephrine on insulin

Answer 8

Reduced insulin secretion

Question 9

Impact of glucagon-like-peptide-1 on insulin

Answer 9

Promotes ca2+ influx and therefore promote the release of insulin

Question 10

Sulphonylurea drug impact on insulin

Answer 10

Encourage K+ channels to close

Question 11

What impact does sympathetic stimulation and epinephrine have on insulin

Answer 11

decrease insulin secretion

Question 12

What else has an influence on insulin

Answer 12

Amino acids
GI hormones
Autonomic nervous system

Question 13

What tissues are metabolic targets

Answer 13

Adipose
Straited muscle
Liver

Question 14

What will an incease in insulin cause

Answer 14

Glucokinase - Glucose -6- PO4- glucose uptake
glycogen synthase - Glycogen storage

ALL INCREASE

Question 15

What will a decrease in insulin cause

Answer 15

increase in
liver pohosphorylase causes increasein glycogen breakdown
increase in phsophatease would a decrease in glucose-6-PO4 which would cause an increase in glucose release

Question 16

What impact does insulin have on the brain

Answer 16

Insulin does not effect glucose uptake in the brain

Question 17

What is insulin converted by

Answer 17

glucagon
adrenaline/noradrenaline
cortisol
growth hormone

Question 18

Where is glucagon produced

Answer 18

Pancreatic alpha cells in islets of langerhans

Question 19

When is glucagon secreted

Answer 19

When blood glucose in low

Question 20

What does glucagon promote

Answer 20

Hepatic glucose release which increases glucogenolysis

Question 21

What does an increase in glucogenolysis cause

Answer 21

An increase in liver phosphorylase casuing an increase in glycogen breakdown and an increase in glucose release

Question 22

When does gluconeogenesis start to occur

Answer 22

When all the glycogen stores have been depleted

Question 23

Features of Type 1 diabetic

Answer 23

Insulin dependent
beta cell dysfucntion
juvenile onset

Question 24

Features of type 2 diabetic

Answer 24

Non - insulin dependent
Insulin resistance
obesity related
> 30 years old

Question 25

Why is there often XS glucose in the urine

Answer 25

It is not al filtered by the PCT

Question 26

What will dehydration cause

Answer 26

increase in blood glucose
Increase in osmolality of ECF
Causing the water to leave the cells

Question 27

What can cause glucotoxicity and what can it lead to

Answer 27

Adherent cellular messaging
chronic inflammation
beta-cell dysfunction
endothelial dysfunction

can lead to tissue damage

Question 28

What else can diabetes casuse

Answer 28

Lead to an increase of ketone in the blood - lowers pH

switch to fat metabolism and increase in hormone sensitive lipase

Question 29

What does a decrease in insulin cause

Answer 29

Increase in the utilisation of fat and protein leading to a depletion of body protein

Question 30

how is diabetes usually diagnosed

Answer 30

urine
Fasting blood glucose
glucose tolerance test
ketoacidosis