Question 420 of 782

Which hormone is primarily responsible for regulating blood glucose levels by promoting the uptake of glucose into cells?

  • Glucagon
  • Insulin
  • Adrenaline
  • Cortisol

Correct Answer: B

Explanation
Correct Option: B. Insulin Detailed Explanation:
  1. Understanding Blood Glucose Regulation:
  2. Blood glucose levels are crucial for maintaining energy homeostasis in the body. The body needs to keep these levels within a specific range to ensure that cells have enough energy to function properly.
  3. The pancreas plays a key role in regulating blood glucose levels through the secretion of hormones, primarily insulin and glucagon.
  4. Role of Insulin:
  5. Insulin is a hormone produced by the beta cells of the pancreas. Its primary function is to lower blood glucose levels.
  6. When blood glucose levels rise after eating (especially carbohydrates), the pancreas releases insulin into the bloodstream.
  7. Insulin facilitates the uptake of glucose by cells, particularly muscle and fat cells, allowing them to use glucose for energy or store it as glycogen for later use.
  8. Insulin also inhibits the production of glucose by the liver, further helping to lower blood glucose levels.
  9. Mechanism of Action:
  10. Insulin binds to insulin receptors on the surface of target cells. This binding triggers a series of intracellular signaling pathways that promote the translocation of glucose transporter proteins (such as GLUT4) to the cell membrane.
  11. Once these transporters are on the membrane, they allow glucose to enter the cell, effectively reducing the concentration of glucose in the bloodstream.
  12. Why Other Options Are Incorrect:
  13. A. Glucagon:
    • Glucagon is produced by the alpha cells of the pancreas and has the opposite effect of insulin. It raises blood glucose levels by promoting the conversion of glycogen to glucose in the liver (glycogenolysis) and stimulating gluconeogenesis (the production of glucose from non-carbohydrate sources). Therefore, glucagon is not responsible for promoting glucose uptake into cells.
  14. C. Adrenaline (Epinephrine):
    • Adrenaline is a hormone released during stress or "fight or flight" situations. It increases blood glucose levels by promoting glycogen breakdown in the liver and inhibiting insulin secretion. While it helps provide energy during emergencies, it does not promote glucose uptake into cells.
  15. D. Cortisol:
    • Cortisol is a steroid hormone released in response to stress and low blood glucose levels. It increases blood glucose levels by promoting gluconeogenesis and reducing glucose uptake in non-essential tissues. Like adrenaline, it does not facilitate glucose uptake into cells.
Summary of Key Points:
  • Insulin is the primary hormone responsible for lowering blood glucose levels by promoting glucose uptake into cells.
  • It is secreted by the pancreas in response to high blood glucose levels, especially after meals.
  • Other hormones like glucagon, adrenaline, and cortisol work to increase blood glucose levels, not decrease them.
  • Understanding the roles of these hormones is crucial for grasping how the body maintains energy balance and responds to dietary intake.
Revision Summary:
  • Insulin lowers blood glucose by promoting cellular uptake of glucose.
  • Glucagon, adrenaline, and cortisol raise blood glucose levels.
  • Insulin is secreted in response to high blood glucose, while the others are secreted during stress or low glucose conditions.
  • The balance between these hormones is essential for metabolic homeostasis.
← Previous Next →
Jump to: 420 421 422 423 424 425 426 427 428 429