Lecture Notes: Blood Glucose Regulation

Overview

• Discussion on how blood glucose concentration is regulated by hormones: insulin and glucagon.
• Explanation of the negative feedback loop involving these hormones.

Blood Glucose Concentration

• Refers to the level of sugar in the bloodstream.
• Adequate glucose is necessary for cellular respiration.
• High blood glucose can damage tissues; thus, balance is crucial.

Role of Insulin

• Function: Lowers blood glucose levels.
• Source: Released by the pancreas.
• Process:
  • After consuming a carbohydrate-rich meal, glucose levels rise as carbohydrates are broken down.
  • Pancreas detects high glucose and releases insulin.
  • Insulin binds to cell receptors, mainly in liver and muscle cells.
  • Promotes uptake of glucose by cells, converting it to glycogen for storage.
  • This decreases blood glucose levels back to normal.

Role of Glucagon

• Function: Increases blood glucose levels.
• Source: Also released by the pancreas.
• Process:
  • When blood glucose levels fall (e.g., skipping meals), the pancreas releases glucagon.
  • Glucagon binds to liver cells, converting stored glycogen back to glucose.
  • Glucose is released into the bloodstream, raising blood glucose levels back to normal.

Negative Feedback Loop

• Mechanism:
  • Insulin and glucagon work together to maintain blood glucose within a tight range.
  • High glucose triggers insulin release; low glucose triggers glucagon release.
  • This creates a dynamic balance, preventing extreme fluctuations.

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