Anatomy & Physiology - Endocrine System

Describe how cortisol influences glucose metabolism and immunity

Cortisol increases blood sugar by promoting gluconeogenesis in the liver, enhancing lipolysis and proteolysis for energy. It also suppresses immune response, inhibiting T-cell activation and cytokine release.

Explain the role of the adrenal medulla in the stress response.

Stressor → CNS → Thalamus → Adrenal medulla stimuilated to release adrenaline + Noradrenaline. → BP ↑, Heart rate ↑, respiratory rate ↑

Describe how insulin promotes glucose uptake into cells

Mainly in : skeletal muscle/adipose tissue.

Insulin bind to the cell membrane receptor (tyrosine kinase) → this activates GLUT-4 to attach to the membrane → Insulin entres → Glycolysis / Glycogenesis.

ADH acts on which part of the nephron?

Collecting duct

Explain the process of Thyroid hormone synthesis.

Iodine + Thyrosine → T3/T4 via Thyroid peroxidase 

1. Iodide uptake by fallicular cells.

2. Iodide oxidise to Iodine (via Thyroid peroxidase)

3. Iodine binds to Tyrosine in Thyroglobulin (protein by Thyroid cells) → Iodination → MIT/DIT

4. MIT+DIT = T3 / DIT+DIT = T4

5. Released into blood. 

Explain how Aldosterone helps maintain blood pressure

Aldosterone acts on renal distal tubules & collecting ducts to increase Na+ and water reabsorption, excretes K+. → Increased blood volume & BP. 

Describe the rold of somatostatin in pancreatic function.

Somatostatin (Delta cell) inhibits secretion of insulin and glucagon, helping balance nutrient metabolism.

Describe how Melatonin secretion is regulated by the light-dark cycle.

Melatonin is secreted by Pineal gland during darkness. Light detected by Retina inhibits hypothalamic signals to the Pineal gland → inhibits the secretion of Melatonin. 

Define SIADH and describe its effects on water balance

Syndrome of inappropriate ADH secretion.

Too much water reabsorbed in Kidney → increased water retention → Hemodilution, Hyponatremia, low urine output.

Growth hormone indirectly stimulates growth by increasing ____ ?

IGF-1