Control of Blood Glucose Concentration Flashcards
Why is the control of blood glucose important?
Blood glucose must be controlled to provide a constant supply of energy for cells, especially the brain, and to prevent damage to tissues from high or low glucose levels.
What is the normal concentration of glucose in the blood?
The normal concentration of glucose in the blood is about 90 mg per 100 cm³ (5 mmol/L).
What hormones are involved in the regulation of blood glucose?
Insulin and glucagon are the two main hormones involved in regulating blood glucose concentration.
What is the role of insulin in regulating blood glucose?
Insulin is secreted by the beta cells of the pancreas and lowers blood glucose by promoting the uptake of glucose into cells, especially liver and muscle cells.
What is the role of glucagon in regulating blood glucose?
Glucagon is secreted by the alpha cells of the pancreas and raises blood glucose by stimulating the liver to convert glycogen into glucose (glycogenolysis).
How does insulin lower blood glucose levels?
Insulin lowers blood glucose by promoting the uptake of glucose into cells for energy and storage as glycogen in the liver and muscle cells.
How does glucagon raise blood glucose levels?
Glucagon raises blood glucose by stimulating glycogenolysis (the breakdown of glycogen into glucose) and gluconeogenesis (the formation of glucose from non-carbohydrate sources) in the liver.
What is glycogenesis?
Glycogenesis is the process of converting glucose into glycogen for storage, primarily in the liver and muscles.
What is glycogenolysis?
Glycogenolysis is the process of breaking down glycogen into glucose, primarily in the liver, to raise blood glucose levels when they are too low.
What is gluconeogenesis?
Gluconeogenesis is the process of producing glucose from non-carbohydrate sources, such as amino acids and glycerol, mainly in the liver.
What is the role of the pancreas in blood glucose regulation?
The pancreas detects changes in blood glucose concentration and releases insulin or glucagon accordingly to maintain a stable blood glucose level.
How does the body respond to a rise in blood glucose?
When blood glucose rises, the pancreas releases insulin, which promotes glucose uptake by cells and the storage of glucose as glycogen in the liver and muscles.
How does the body respond to a drop in blood glucose?
When blood glucose drops, the pancreas releases glucagon, which stimulates the liver to break down glycogen into glucose and release it into the blood.
What is the role of the liver in controlling blood glucose levels?
The liver stores glucose as glycogen when blood glucose is high and releases glucose from glycogen when blood glucose is low, helping to stabilize glucose levels.
What is type 1 diabetes?
Type 1 diabetes is an autoimmune disease where the immune system attacks the beta cells of the pancreas, preventing insulin production and leading to high blood glucose levels.
What is type 2 diabetes?
Type 2 diabetes is a condition where the body becomes resistant to insulin or the pancreas doesn’t produce enough insulin, leading to high blood glucose levels.
How is type 1 diabetes treated?
Type 1 diabetes is treated with regular insulin injections or an insulin pump to control blood glucose levels.
How is type 2 diabetes treated?
Type 2 diabetes is treated with lifestyle changes (diet and exercise), oral medications, and sometimes insulin if the condition progresses.
What is the role of beta cells in the pancreas?
Beta cells in the pancreas secrete insulin in response to high blood glucose levels, helping to lower glucose levels in the blood.
What is the role of alpha cells in the pancreas?
Alpha cells in the pancreas secrete glucagon in response to low blood glucose levels, helping to increase blood glucose by stimulating glycogenolysis and gluconeogenesis.
What is the second messenger model of adrenaline action?
The second messenger model of adrenaline action involves adrenaline binding to a receptor on the cell surface, activating an enzyme called adenylate cyclase. This enzyme converts ATP into cyclic AMP (cAMP), which then activates protein kinases, leading to a cascade of reactions inside the cell, resulting in the desired physiological response (e.g., increased heart rate).
What is the second messenger model of glucagon action?
The second messenger model of glucagon action works similarly to adrenaline. Glucagon binds to a receptor on liver cells, activating adenylate cyclase. This converts ATP into cyclic AMP (cAMP), which then activates protein kinases, triggering glycogenolysis (the breakdown of glycogen into glucose) to raise blood glucose levels.
How does cyclic AMP (cAMP) function as a second messenger?
Cyclic AMP (cAMP) acts as a second messenger by activating protein kinases, which then phosphorylate target proteins inside the cell. This phosphorylation leads to various cellular responses, such as the activation of enzymes like glycogen phosphorylase in the case of glucagon, facilitating the breakdown of glycogen into glucose.
What is the role of protein kinases in the second messenger model?
Protein kinases are enzymes activated by cyclic AMP (cAMP) in the second messenger model. They phosphorylate specific proteins in the cell, altering their activity and triggering cellular responses, such as the activation of enzymes involved in glycogen breakdown in liver cells.
How does the second messenger model amplify the signal of adrenaline and glucagon?
The second messenger model amplifies the signal because a small amount of adrenaline or glucagon binding to a receptor can lead to the production of many molecules of cAMP. This, in turn, activates many protein kinases, resulting in a large number of molecules being activated in the cell, amplifying the physiological response.
