Glucoregulation Flashcards
What are normal blood glucose levels?
4-6mmolL
Pancreatic islet alpha and beta cells release what?
Glucagon - alpha cells
Insulin - beta cells
Glycogenolysis?
Glycogen - large group of glucose
lysis - break apart
Breaks apart glycogen, increases blood glucose level.
Gluconeogenesis?
Gluco (sugar) neo (new) genesis (make)
Creation of new glucose from protein and fat.
What is glycogenesis?
Creation of glycogen (large clump of glucose) from glucose, decreases blood glucose level.
Lipogenesis
Creation of lipids (fat) from glucose, decreases blood glucose levels.
How is glucose obtained from diet?
Through ingestion of carbohydrates, which are broken down into glucose by digestive enzymes.
What is the equation for cellular respiration?
C6H12O6 + (6)O2 –> (6)CO2 + (6)H2O + ATP
Where is glycogen stored?
The liver and muscle cells.
What is hypoglycaemia?
Hypo - low
Glyc - glucose
Aemia - blood
Low blood glucose.
What is hyperglycaemia?
Hyper - high
Gly - glucose
Aemia - blood
High blood sugar
What can hyperglycaemia result in?
Cardiovascular damage Neurological damage Kidney damage Retinal damage Ulcers on the feet and legs (neuropathy)
What causes hypoglycaemia? What can hypoglycaemia result in?
If a diabetic patient has exercised too much, tumours, kidney or liver failure.
Clumsiness, trouble talking, confusion, loss of consciousness, death.
Why is the liver especially important in glucoregulation?
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.
How does insulin decrease blood sugar levels?
Promotes glycogenesis
Promotes uptake of glucose into cells (particularly skeletal muscle)
Promotes lipogenesis
Promotes protein synthesis
Where is glycogen stored in the body? How much glycogen can the body store?
Liver and muscle cells.
~500g
Why does protein synthesis decrease blood sugar levels?
Protein synthesis requires energy to occur, uses energy from glucose.
How does the body increase blood sugar levels?
1) Glycogenolysis (glycogen breakdown)
2) Lipolysis (fat breakdown)
3) Gluconeogenesis
4) Release of glucocorticoids (cortisol)
5) Release of adrenaline and noradrenaline
How long can glycogen supply glucose for?
~6 hours
What is the difference between glycogenolysis and gluconeogenesis?
Gluconeogenesis occurs more slowly (needs time to mobilise adipose tissue)
Gluconeogenesis uses fats and amino acids, glycogenolysis uses glycogen
Which hormone promotes gluconeogenesis?
Glucagon
How are glucocorticoids involved in glucoregulation?
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.
What are the 3 ways that cortisol increases blood sugar?
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
