Adrenal Disease - Adrenal Physiology

Question 1

What is the HPA Axis?

Answer 1

1. Hypothalamus - CRH (Corticotrophin Release Hormone).
2. Anterior Pituitary - ACTH (Adrenocorticotrophic Hormone).
3. Adrenal Gland - Cortisol.

Question 2

How is Cortisol released?

Answer 2

Pulses, in response to a stressful stimulus with diurnal variation (peaking in the early morning and stooping at evening).

Question 3

What effects does Cortisol have on the body (5)?

Answer 3

1. Inhibits Immune System.
2. Inhibits Bone Formation.
3. Raises Blood Glucose.
4. Increases Metabolism.
5. Increases Alertness.

Question 4

Sections and Products of the Adrenal Gland (3).

Answer 4

1. Zona Glomerulosa - Mineralocorticoids.
2. Zona Fasciculata - Corticosteroids.
3. Zona Reticularis - Androgens.

Question 5

RAAS.

Answer 5

1. JGA cells in Afferent Arteriole of Kidney detect low BP and secrete Renin.
2. Renin converts Angiotensinogen from Liver into Angiotensin I.
3. ACE converts Angiotensin I into Angiotensin II in the lungs.
4. Angiotensin II stimulates release of Aldosterone from Adrenal Glands.

Question 6

Effects of Aldosterone (3).

Answer 6

1. Increased Sodium Resorption at the DCT.
2. Increased Potassium Secretion from the DCT.
3. Increased Hydrogen Secretion from the Collecting Ducts.