control of blood glucose Flashcards
Where is insulin released and when?
beta cells, the islet of Langerhans, blood glucose too high
What does insulin do?
binds to receptors on the liver this stimulates conversion of glucose to glycogen reducing blood glucose conc
what is glycogenesis?
the conversion of glucose to glycogen
Where is glucagon released and when?
alpha cells in the islet of Langerhans, blood glucose too low
what does Glucagon do?
bind to receptor cells in the liver this stimulates the conversion of glycogen to glucose, raising blood glucose concentration
What is glycogenolysis?
the conversion of glycogen to glucose
what does the adrenal cortex do?
releases cortisol which is secreted when glycogen stores run out. It stimulates gluconeogenesis which increases glucose levels quickly.
what does the adrenal medulla do?
This releases adrenaline and causes glycogenolysis
How does adrenaline cause glycogen to turn into glucose?
Adrenaline, the first messenger, binds to receptors on the cell surface membrane to give birth to hormone-receptor complex. The formation of the complex causes the enzyme adenylate cyclase/adenylyl cyclase to be activated.It catalyses the conversion of ATP into cyclic AMP which is the second messenger cyclic AMP activates an enzyme, Protein Kinase A/Protein Kinase, in the cell which starts a cascade of reactions. The last reaction to occur is the conversion of glycogen into glucose (glycogenolysis).
What is type one diabetes, how can it be managed?
This occurs suddenly in childhood. The body is unable to produce any insulin and is thought to be because the beta cells of the islets of Langerhans in the pancreas have been targeted by the immune system. The levels of glucose can be controlled by regular injections with insulin and the careful management of diet and exercise.
What is type two diabates?
This occurs mainly in people over the age of 40 however it is becoming increasingly more common in adolescents too. This condition arises when the insulin receptors are no longer responsive to insulin or an inadequate amount of insulin is being made by the beta cells. This too can be controlled by the careful management of diet and exercise.
