Glucoregulation

Question 1

What are normal blood glucose levels?

Answer 1

4-6mmolL

Question 2

Pancreatic islet alpha and beta cells release what?

Answer 2

Glucagon - alpha cells

Insulin - beta cells

Question 3

Glycogenolysis?

Answer 3

Glycogen - large group of glucose
lysis - break apart

Breaks apart glycogen, increases blood glucose level.

Question 4

Gluconeogenesis?

Answer 4

Gluco (sugar) neo (new) genesis (make)

Creation of new glucose from protein and fat.

Question 5

What is glycogenesis?

Answer 5

Creation of glycogen (large clump of glucose) from glucose, decreases blood glucose level.

Question 6

Lipogenesis

Answer 6

Creation of lipids (fat) from glucose, decreases blood glucose levels.

Question 7

How is glucose obtained from diet?

Answer 7

Through ingestion of carbohydrates, which are broken down into glucose by digestive enzymes.

Question 8

What is the equation for cellular respiration?

Answer 8

C6H12O6 + (6)O2 –> (6)CO2 + (6)H2O + ATP

Question 9

Where is glycogen stored?

Answer 9

The liver and muscle cells.

Question 10

What is hypoglycaemia?

Answer 10

Hypo - low
Glyc - glucose
Aemia - blood

Low blood glucose.

Question 11

What is hyperglycaemia?

Answer 11

Hyper - high
Gly - glucose
Aemia - blood

High blood sugar

Question 12

What can hyperglycaemia result in?

Answer 12

Cardiovascular damage
Neurological damage
Kidney damage
Retinal damage
Ulcers on the feet and legs (neuropathy)

Question 13

What causes hypoglycaemia? What can hypoglycaemia result in?

Answer 13

If a diabetic patient has exercised too much, tumours, kidney or liver failure.

Clumsiness, trouble talking, confusion, loss of consciousness, death.

Question 14

Why is the liver especially important in glucoregulation?

Answer 14

1) glycogenesis and glycogenolysis can both occur here
2) Liver receives blood from hepatic portal vein, which receives blood from veins directly from the intestines. Thus the liver is the first destination for new nutrients which have just been absorbed.

Question 15

How does insulin decrease blood sugar levels?

Answer 15

Promotes glycogenesis
Promotes uptake of glucose into cells (particularly skeletal muscle)
Promotes lipogenesis
Promotes protein synthesis

Question 16

Where is glycogen stored in the body? How much glycogen can the body store?

Answer 16

Liver and muscle cells.

~500g

Question 17

Why does protein synthesis decrease blood sugar levels?

Answer 17

Protein synthesis requires energy to occur, uses energy from glucose.

Question 18

How does the body increase blood sugar levels?

Answer 18

1) Glycogenolysis (glycogen breakdown)
2) Lipolysis (fat breakdown)
3) Gluconeogenesis
4) Release of glucocorticoids (cortisol)
5) Release of adrenaline and noradrenaline

Question 19

How long can glycogen supply glucose for?

Answer 19

~6 hours

Question 20

What is the difference between glycogenolysis and gluconeogenesis?

Answer 20

Gluconeogenesis occurs more slowly (needs time to mobilise adipose tissue)
Gluconeogenesis uses fats and amino acids, glycogenolysis uses glycogen

Question 21

Which hormone promotes gluconeogenesis?

Answer 21

Glucagon

Question 22

How are glucocorticoids involved in glucoregulation?

Answer 22

Hypothalamus triggers the release of adrenocorticotopic hormone from the anterior pituitary gland. ACTH triggers the release of cortisol from the adrenal cortex. Cortisol increases blood sugar.

Question 23

What are the 3 ways that cortisol increases blood sugar?

Answer 23

1) Stimulates glycogenolysis
2) Facilitates transport of amino acids out of muscle for use in gluconeogenesis
3) Mobilises fatty acids from adipose tissue to be used for their metabolic energy
4) Stimulates the adrenal medulla to release adrenaline and noradrenaline - encourages use of glycogen in anaerobic respiration