Understanding Blood Sugar Regulation For Medical Students

Understanding Blood Sugar Regulation For Medical Students

Question 1. Give the normal blood glucose level. Name the hormones that affect blood glucose level give four Important functions of insulin.
Answer:

Normal blood glucose level:

• Normal fasting blood glucose is 70-90 mg/dl.
• Postprandial blood glucose is 120-140 mg/dl.

Hormones that affect blood glucose level:

1. Insulin.

• Decreases blood sugar level by.
  1. Facilitating transport of glucose.
  2. Facilitates uptake of glucose by cells.
  3. Increases peripheral utilization of glucose.
  4. Decreases glucose output from the liver.
  5. Increases glycogenesis.
  6. Prevents glycogenolysis.
  7. Prevents gluconeogenesis.

2. Glucagon.

• It increases the blood sugar level by.
  1. Stimulating glycogenolysis.
  2. Promoting gluconeogenesis.
  3. Utilizing amino acids for glucose formation.

Question 2. What is normal serum calcium level? Name hormones regulating it. Describe the functions of parathormone.
Answer:

Normal serum calcium level:

• 9-11 mg/dl

Hormones regulating normal calcium level:

• Calcium concentration is regulated by the action of following hormones

1. Vitamin D

• Increases calcium level by
  • Increasing calcium from the small intestine
  • Stimulates osteoclasts to mobilize calcium into ECF from bones
  • Increases reabsorption of calcium from renal tubules

2. Parathormone

• Increases plasma calcium by promoting bone resorption
  • Increases reabsorption of calcium from renal tubules and decreases its excretion
  • Increases calcium absorption from gut

3. Calcitonin

• Inhibits osteoclast activity
• Inhibits calcium absorption from intestine

Functions of parathormone (PTH):

1. On bones

• PTH stimulates osteoclasts and osteoblast to cause resorption of calcium from bones
• Thus, it increases plasma calcium and decreases plasma phosphate

2. On kidneys

• Increases reabsorption of calcium from renal tubules
• Thus decreases calcium excretion in urine and increases serum calcium level
• PTH decreases reabsorption of phosphate
• Increases formation of 1,25-dihydroxycholecalciferol from 25-hydroxycholecalciferol

3. On GIT

• Increases calcium absorption from gut

4. On lactating mothers

• Decreases the amount of calcium secreted into the milk