Blood sugar levels 

  • glucose is required for cell respiration
  • glucose must be present in the blood at all times
  • the levels have to be kept within certain limits to prevent damage to the body
  • too high or low you may die

control of blood glucose

  • 2 hormones control glucose levels
  • insulin and glucagon
  • these are released from the islets of Langerhans
  • alpha cells release glucagon
  • beta cells release insulin

rise in glucose levels

  • absorption of carbohydrates such as starch and sugars after a meal
  • starch is broken down into glucose before absorption
  • glucose is absorbed by the small intestine
  • blood glucose levels will rose

response to rise in glucose levels

  • conversion of amino acids to glycerol and glucose.excess amino acids absorbed from food cannot be stored,they are deaminated in the liver
  • the amino part is converted into urea and excreted.the rest of the molecule is converted into glucose
  • conversion of glycogen into glucose

effects of insulin

  • released when glucose levels rise
  • target cells are liver and muscle
  • cause these cells to take up glucose by increasing their membrane permeability by adding more transport proteins to the membrane
  • glucose uptake is by facilitated diffusion
  • stimulate the cells to produce an enzyme that converts soluble glucose into insoluble glycogen
  • the glycogen will act as a glucose store
  • as a result blood glucose levels fall
  • they are stored as glycogen rather than glucose so that the balance of the cell is not disturbed

effects of insulin

  • increases the rate of respiration to lower glucose levels
  • increases the rate of conversion of glucose into fat in adipose cells

 %%⭐ blood glucose rises → detected by beta cells → beta cells release insulin → blood glucose levels fall to normal → detected by beta cells → reduce insulin production.%%

effects of glucagon

  • released when glucose levels fall
  • target cells are liver cells
  • cause cells to produce an enzyme that converts glycogen to glucose
  • gluconeogenesis
  • causes the cells to release the glucose into blood
  • glucose levels in the blood will rise - bringing it back to normal

%%⭐ blood glucose levels fall → detected by the alpha cells → alpha cells release glucagon → blood glucose levels fall to normal → detected by alpha cells → reduce glucagon production%%