🍬 Control of Blood Glucose

Why it’s important

• Glucose = needed by all cells for respiration (energy).

• Blood glucose concentration must be kept constant → part of homeostasis.

• Monitored by the pancreas.

📈 When blood glucose is too high (after a carbohydrate-rich meal):

• Pancreas releases insulin.

• Insulin:

  • Triggers body cells to absorb glucose.

  • Triggers liver + muscle cells to store excess glucose as glycogen.

• Blood glucose returns to normal level.

📉 When blood glucose is too low (between meals) → Higher tier only:

• Pancreas releases glucagon.

• Glucagon:

  • Causes liver cells to break down glycogen → glucose.

  • Glucose released into blood.

• Blood glucose returns to normal.

• Insulin & glucagon form a negative feedback cycle (opposite effects, maintain balance).

🩸 Diabetes

Type 1 Diabetes

• Pancreas produces little/no insulin.

• Blood glucose rises dangerously high after meals.

• Treated by:

  • Monitoring blood glucose.

  • Insulin injections.

Type 2 Diabetes

• Body cells no longer respond to insulin.

• Linked to obesity (major risk factor).

• Treatment:

  • Controlled carbohydrate diet.

  • Exercise.

• Increasing in the UK due to rising obesity levels.

✅ Exam tips:

• Be able to describe what happens after a meal vs between meals.

• Know the difference between Type 1 and Type 2 diabetes (cause + treatment).

• Higher tier → learn glucagon and negative feedback cycle.