Adrenal Hormones Flashcards
What NS innervates the adrenal medulla?
sympathetic innervation
What cells are included in the adrenal medulla?
Chromaffin cells
What does the adrenal medulla secrete?
Catecholamines
90% cells produce epi, 10% produce NE
What does the adrenal cortex secrete?
Corticosteroids
Bulk of the gland
What is the adrenal cortex stimulated by?
Stimulated by the ACTH
True/False: Adrenal cortex is key to survival?
- True
A. Vital to survival
B. Trauma to or removal of the adrenal glands requires corticosteroid supplementation throughout life
What is the function of the adrenal cortex?
- Different functional categories of steroid hormones are synthesized and secreted in three separate zones
A. Regulates salt, sugar, and sex
What are the 3 zones of the adrenal cortex and what do they produce?
1. Zona glomerulosa A. Aldosterone 2. Zona fasiculata B. Cortisol and Androgens 3. Zona reticularis A. androgen precursors
What are the general characteristicsof the zona glomerulosa?
- Produces mineralcorticoids
A. Principal mineralcorticoid is aldosterone
What is the function of aldosterone?
Outer layer
1. Affects Na metabolism
A. Increases tubular transport Na
B. Causes re-absorption Na, Cl, HCO3, & water
C. Causes excretion K
2. Secretion of these cells controlled by extracellular fluid concentrations of angiotensin II & K
A. Increase in either of above increases aldosterone secretion
What are the general characteristics of the zona fasciulata?
- Middle Layer
2. Produces glucocorticoids
What is the function of the glucocorticoids?
- Cortisol is the principal glucocorticoid
- Stimulates metabolism of lipids, proteins, glucose
- Anti-inflammatory effects
A. Inhibit WBC’s & other components of immune system - Also secretes small amounts androgens & estrogens
- Secretion of glucocorticoids is controlled by hypothalamic-pituitary axis via ACTH
What are the characteristics of the zona reticularis?
- Inner most layer
- Produces sex hormones
A. Androgens - Can also produce small amounts of cortisol
- Regulated by ACTH
A. Physiology not well understood
What are the actions of cortisol?
- muscle wasting
- gluconeogenesis
- hyperglycemia
- anti-inflammatory
- anti-immune effects
- insulin resistance
- It also has mineralocorticoid-like effects on the kidney at high concentrations.
How are glucocorticoids involved in carbohydrate metabolism?
- Stimulate gluconeogenesis
A. Formation of carbohydrates from proteins & other substances by liver - Cause decrease in rate of glucose utilization by most cells in body
- Cause increased insulin
A. Leads to insulin resistance
How are glucocorticoids involved in protein metabolism?
- Stimulates protein catabolism
A. Promotes amino acid mobilization from muscle to provide amino acids for gluconeogenesis - Increased protein catabolism and decreased protein synthesis leads to reduced protein stores (except liver)
- Increased liver proteins and plasma proteins
A. Inc liver & plasma proteins
B. Results from transport of proteins via plasma to liver for gluconeogenes
How are glucocorticoids involved in fat metabolism?
- Promotes mobilization fatty acids from adipose tissue
2. Shifts primary energy source to fatty acids
How are glucocorticoids involved with stress/inflammation?
- Stress causes increase ACTH which causes increase in cortisol secretion
- Different types of stress
A. Trauma
B. Infection
C. Surgery
D. Emotional