Adrenal Glands Flashcards
(23 cards)
What is the hypothalamic pituitary adrenal axis?
- The hypothalamus releases CRH
- CRH stimulates the anterior pituitary gland to release ACTH
- ACTH stimulates the adrenal cortex to produce cortisol
What are the two main classes of hormones produced by the adrenal cortex?
- Glucocorticoids
- Mineralocorticoids
What does ACTH stand for?
Adrenocorticotropic hormone
What does ACTH do?
Stimulates the adrenal cortex to produce and release glucocorticoids like cortisol
How is cortisol transported in the blood?
- 75% bound to CBG
- 15% bound to albumin
- 10% is free and active
How is aldosterone transported in the blood?
- 50% bound to albumin
- 10% bound to CBG
- 40% is free
What are the key metabolic actions of glucocorticoids?
- Increase gluconeogenesis, lipolysis, protein catabolism
- Decrease inflammatory cytokines and lymphocyte numbers
How do glucocorticoids affect carbohydrate metabolism?
- Stimulates gluconeogenesis
- Inhibits peripheral glucose uptake
- Increase liver glycogen synthesis
How do glucocorticoids affect fat metabolism?
- Increase of lipolysis
- Redistribution of fat
- Enhance effect of GH, glucagon and catecholamines
How do glucocorticoids affect protein metabolism?
- Stimulate liver protein synthesis
- Inhibit protein synthesis elsewhere
- Promote muscle breakdown and decreased bone cartilage development
How do glucocorticoids affect lymphoid tissue and immunity?
- Decrease in lymphocytes and eosinophils
- Decrease in cell and antibody mediated immunity
How do glucocorticoids affect the nervous system?
- Decrease EEG activity
- Increased appetite, depression and altered smell and taste sensitivity
How do glucocorticoids produce anti-inflammatory effects?
- Inhibit phospholipase A2
- Decrease histamine release and capillary permeability
How do glucocorticoids affect water balance?
- Inhibit ADH which increases urine output
- Increases GFR in kidneys
What is cortisol’s role in fetal development?
Prepares foetus for birth by stimulating lung surfactant, hepatic and digestive enzymes and helps initiate labour
What is Cushing’s disease?
When there is an excess of cortisol levels
What are signs of Cushing’s disease?
- Muscle wasting
- Pot belly
- Alopecia
- Skin thinning
- Enlarged liver
What is Addison’s disease?
When there is a cortisol deficiency
What are the signs of addison’s disease?
- Decreased blood pressure
- Vomiting
- Weakness
- Lost weight
- Dehydration
What is the primary mineralocorticoid?
Aldestrone
What does aldosterone do?
- Regulates sodium, potassium and water balance
- Regulates blood pressure
How does the renin-angiotensin system regulate aldosterone?
- Decrease in blood pressure
- Kidney releases renin
- Produces angiotensin II
- Angiotensin II stimulates the adrenal cortex to increase aldosterone
What happens when aldosterone is deficient?
Loss of Na+ and water balance resulting in death
