In females, the adrenal androgens play a role in libido and are converted into estrogens by other body tissues.
Regulation:
Mineralcorticoids are controlled through CRH & ACTH in a negative FB system and directly by blood pressure/ volume levels. As blood pressure or volume decreases, aldosterone is stimulated to be released to raise blood pressure or volume. Glucocorticoids are controlled through CRH, ACTH and blood levels of cortisol in a negative FB system. Androgens are controlled through CRH, ACTH & testosterone/estrogen levels in a negative FB system.
Adrenal Medulla
The adrenal medulla is a modified Sympathetic Ganaglion of the ANS but rather than release a neurotransmitter, it releases a hormone. Secretory cells: The hormone-producing cells are called Chromaffin Cells and are innervated by sympathetic preganglionic neurons of the ANS. Release of these hormones occurs quickly due to the direct control of these cells by the ANS. Hormones: The two major hormones produced by the chromaffin cells are: Epinephrine aka Adrenaline, and Norepinephrine (NE) aka Noradrenaline . Production of these hormones is unequal with ~80% epinephrine and 20% NE being produced.
Target: all body cells.
Function: Unlike hormones of the adrenal cortex, these hormones are NOT essential for life but only intensify sympathetic responses in other parts of the body. Epinephrine and NE can increase heart rate and force of contraction therefore increasing output of the heart and increasing blood pressure. In addition, they: increase blood flow to the heart, liver, skeletal muscles, and adipose tissue; dilate airways to the lungs, dilate the pupils; increase blood levels of glucose and fatty acids.
Regulation:
In stressful situations (fight or flight response), the hypothalamus stimulates the sympathetic preganglionic neurons, which stimulates the chromaffin cells to secrete epinephrine and NE.
Clinical Disease: Cushings, Let-Down Syndrome, Anhydrosis, Chronic Stress
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