HRMS 3

What is a goiter and how can both hypothyroidism and hyperthyroidism cause it?

• Goiter: Enlargement of the thyroid gland.

• Hyperthyroidism: Caused by excessive TSH stimulation despite normal iodine levels → overgrowth of thyroid.

• Hypothyroidism: Caused by low iodine → low TH → pituitary releases excess TSH to compensate → thyroid enlarges.

What are the effects of parathyroid hormone (PTH) on the body?

• Bones: Stimulates calcium release into the blood.

• Digestive system (Intestines): Increases calcium absorption via Vitamin D (calcitriol).

• Urinary system (Kidneys): Reduces calcium excretion by increasing reabsorption.

• Note: Calcitonin is the antagonistic hormone (lowers calcium levels).

How is aldosterone release controlled?

1. Low blood pressure or sodium levels trigger the production of angiotensin II.

2. Angiotensin II stimulates the adrenal cortex to release aldosterone.

3. Aldosterone acts on the kidneys to:
   

   • Retain sodium and water

   • Excrete potassium

   • Raise blood pressure and restore electrolyte balance

What is ketoacidosis and what causes it?

• Ketoacidosis: Build-up of ketone bodies in the blood.

• Caused when cells can’t use glucose (due to lack of insulin) and instead break down fat for energy (ATP).

• Fat metabolism → ketone byproducts → acidic blood

What are the symptoms and effects of insulin deficiency (diabetes mellitus)?

• Cause: Cells can’t absorb glucose without insulin → high blood glucose

• Symptoms:
  

  • Increased hunger and thirst

  • Frequent urination (glucose excreted in urine)

  • Lack of energy (cells can’t access glucose)