Control of Blood Glucose Concentration

aqa

where is insulin the hormone released?

it is released from B cells in the pancreas

why is insulin being released?

when blood glucose concentration rises in order to lower the concentration back to its optimum

what is insulin an example of?

negative feedback

describe what happens when blood glucose rises?

- insulin will bind to an insulin receptor
- vesicles of glucose transporters fuse with the plasma membrane
- allowing more glucose to enter the cell
- cell is also used to more glucose in respiration
- enzyme is activated to convert glucose to glycogen (glycogenesis)

describe what happens when blood glucose level decreases?

- alpha cells detects the change
- hormone glucagon is released in the adrenal gland and releases adrenaline
- second messenger model occurs
- activating enzymes which breaks down glycogen to glucose ( glycogenolysis)
-producing glucose from other molecules
- more glucose is released back to blood

glycogenesis

process of excess glucose being converted to glycogen when glucose is higher than normal (in liver)

glucogenolysis

hydrolyses glycogen back to glucose in liver which occurs when blood glucose is lover

gluconeogenesis

this is the process of creating glucose from non carbohydrate and stores in the liver which occurs is glycogen has been hydrolysed to glucose and need more glucose

role of glucagon

- alpha cells detects when glucose is too low
- secrete glucagon
- glucagon will attach the receptors on the surface of liver cells
- glucagon binds and causes protein to be activated into adenylate cyclase
- converts to ATP in cyclic AMP
- activates enzyme protein kinase and hydrolyses glycogen to glucose
- activating enzymes will involve in the conversion of glycerol from lipids to amino acid to glucose

role of adrenaline

- if glucose concentration is too low the adrenal gland will also secrete adrenaline
- adrenaline attach to receptors on the surface of target cells
- causes G protein to be activated
converts ATP cAMP
- cAMP activates the enzyme that can hydrolyse glycogen into glucose

what is the formation of cAMP?

it acts as a second messenger

what are diabetes?

diabetes is a conditon where the concentration of glucose in the blood cannot be controlled effectively
- can lead to hyper and hypo glycaemia

what is type 1 diabetes

it is caused by an autoimmune attack on the b cells of the pancreas
- b cells cannot detect the changes in the body
- body cannot produce insulin
- be treated by insulin injection

type 2

- this is caused because the body cannot produce enough insulin
- target cells loses their responsiveness to insulin
- develops in adulthood which is because of obesity and poor diet
- controlled by regulating intake of carbohydrates
- by increasing excercise and maybe insulin injections