Adrenal Hormones Flashcards
What does the adrenal gland consist of?
- Cortex.
- Medulla.
What does the cortex of the adrenal gland secrete?
Adrenocorticoids and adrenal androgens.
What does the medulla of the adrenal gland secrete?
Epinephrine (adrenaline).
Into how many zones is the adrenal cortex divided?
Three zones.
From what does the adrenal cortex’s three zones synthesize various steroids?
Cholesterol.
What does the outer layer of the adrenal cortex produce?
Mineralocorticoids (e.g., aldosterone).
What does the middle layer of the adrenal cortex synthesize?
Glucocorticoids (e.g., cortisol also known as hydrocortisone).
What does the inner layer of the adrenal cortex secrete?
Adrenal androgens (e.g., dehydroepiandrosterone).
What controls the secretion of the two inner zones and the outer zone of the adrenal cortex?
Pituitary ACTH.
What serves as feedback inhibitors of ACTH and CRH secretion?
Glucocorticoids.
List four therapeutic uses of adrenal cortex hormones.
Replacement therapy, treatment and management of asthma and other inflammatory diseases (e.g., rheumatoid arthritis), treatment of severe allergic reactions, and treatment of some cancers.
Where do adrenocorticoids bind in target tissues?
To specific intracellular cytoplasmic receptors. (They are lipophilic and can penetrate cell membranes)
How is the distribution of glucocorticoid receptors different from mineralocorticoid receptors?
Glucocorticoid receptors are widely distributed throughout the body, whereas mineralocorticoid receptors are mainly confined to excretory organs like the kidney, colon, and salivary and sweat glands.
Which type of receptor has a wider spectrum of activity, glucocorticoid or mineralocorticoid?
Glucocorticoid.
What is the principal glucocorticoid?
Cortisol.
How is glucocorticoid production characterized diurnally?
Peak early in the morning, followed by a decline, then a smaller peak in the late afternoon.
What factors influence glucocorticoid secretion?
Stress.
How do glucocorticoids favor gluconeogenesis?
By stimulating protein catabolism (except in the liver) and lipolysis, providing building blocks for glucose synthesis, leading to hyperglycemia.
How do glucocorticoids increase resistance to stress?
By raising plasma glucose levels, providing the body with energy to combat stress.
How do glucocorticoids affect blood pressure?
They can cause a modest rise by enhancing vasoconstrictor action of adrenergic stimuli on small vessels.
How do glucocorticoids alter blood cell levels in plasma?
Decrease eosinophils, basophils, monocytes, and lymphocytes; increase hemoglobin, erythrocytes, platelets, and neutrophils.
What are the anti-inflammatory actions of glucocorticoids?
Reduce the inflammatory response and suppress immunity by lowering and inhibiting peripheral lymphocytes and macrophages, inhibiting phospholipase A2, reducing COX-2 synthesis, and decreasing histamine release.
How do glucocorticoids affect other components of the endocrine system?
Feedback inhibition of ACTH and TSH production, and increased GH production.
Why is adequate cortisol essential?
For normal renal glomerular filtration (GF).