14.3 Regulation Of Blood Glucose Concentration Flashcards
What increases blood glucose concentration?
Diet
Goycogenolysis
Gluconeogenesis
Glycogenolysis
Glycogen stores in the liver and muscle cells is broken down into glucose and released into bloodstream
Gluconeogenesis
Production of glucose from non carbohydrate sources eg glycerol and amino acids
What decreases blood glucose levels?
Respiration
Glycogenesis
Glycogenesis
Production of glycogen
When blood glucose concentration is too high, excess glucose is converted into glycogen
Body cell that does not have insulin receptor on cell surface membrane
Red blood cells
How does insulin lower blood glucose concentration?
Increase absorption of glucose by cells
Increase respiratory rate I’d cells
Increase Glycogenesis
Increase rate of glucose to fat conversion
Inhibit release of glucagon from alpha cells
Body cells that have receptors for glucagon
Liver and fat cells
How does glucagon raise blood glucose concentration?
Glycogenolysis - liver breaks down glycogen into glucose and release into bloodstream
Reducing glucose absorption by liver cells
Increase gluconeogenesis - increase conversion of amino acids and glycerol into glucose
Antagonistic hormones
Work against each other - glucagon and insulin
Control of insulin secretion
1) At normal blood glucose concentration, potassium channels in the plasma membrane of beta cells are open - K+ ions diffuse out of the cell -70mV potential
2) Blood glucose concentration rises, glucose enters cell by glucose transporter
3) Glucose is metabolised inside the mitochondria, causing ATP production
4) ATP binds to potassium channels and causes them to close - ATP sensitive potassium channels
5) K+ ions cannot diffuse out of cell, pd reduces to -30mV, depolarisation occurs
6) Depolarisation causes voltage gated calcium channels to open
7) Ca2+ ions enter the cell and cause secretory vesicles to release insulin they contain by exocytosis
