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What hormones are released by the posterior pituitary?
Antidiuretic hormone (ADH) - also known as vasopressin and oxytocin
What is the function of ADH?
- Controls water homeostasis by affecting the permeability of the collecting tubules of the kidney and enhancing water resorption, making urine more concentrated and the blood more dilute
- Raises blood pressure by stimulating musculature of arterioles and capillaries
- Affects uterine contraction
- Promotes intestinal muscle contraction
What causes an increase level of ADH?
- Syndrome of inappropriate ADH secretion (SIADH) - no known stimulus for the release
- Small cell carcinoma of the lung
- CNS disease
- Pulmonary disease
- Side effect of certain drugs
What clinical conditions results in decreased levels of ADH?
- Diabetes insipidus
What is the function of oxytocin?
- Stimulates uterine contractions during childbirth
- Causes the ejection of breast milk
Name the 3 layers of the Adrenal cortex
- Zona glomerulosa (outermost)
- Zona fasciculata (2nd layer)
- Zona reticularis (3rd layer)
What does the zona glomerulosa secrete?
- (Aldosterone is the major one)
What does the zona fasciculata secrete?
- (Cortisol is the major one)
What does the zona reticularis secrete?
- Sex hormones
- (principally the androgens)
What is the inner portion of the adrenal gland?
What does the adrenal medulla produce?
- Amine hormones
- (epinephrine and norepinephrine)
What are collectively known as catecholamines?
What secretes the steroid hormones?
Name the 3 groups of steroid hormones
What regulates salt balance?
What assists with carbohydrate metabolism?
What is required for sexual function?
What controls the retention of Na, Cl, and H2O, the excretion of K and H, and the amount of fluid in the body?
What is aldosterone production controlled by?
Renin-angiotensin system of the kidneys
What is produced when there is a decrease in blood pressure or blood volume?
What is a protein that acts on angiotensinogen to produce angiotensin I?
What stimulates the secretion of aldosterone and is a potent vasoconstrictor?
What is the function of aldosterone?
- Increase salt
- Water conservation
- Overall effect is vasoconstriction
What is the reference range of aldosterone?
- Adult supine: 3-16 ng/dL
- Adult upright: 7-30 ng/dL
- Levels are higher in the morning
What is the clinical significance of hyperaldosteronism?
- Primary hyperaldosteronism: adrenal disease (Conn syndrome)
- Secondary hyperaldosteronism: Renin-angiotensin system disorder, malignant hypertension, or renin-secreting renal tumor
What is the clinical significance of hypoaldosteronism?
- Atrophy of the adrenal glands
- Addison disease
- Congenital deficiency of 21-hydroxylase enzyme
Pigmemtation of the skin
Decreased blood pressure
Atrophy of adrenal glands
Depressed production of aldosterone and glucocorticoid
Name the physiological effects of cortisol
- Anti-insulin effects on carbs that result in increased blood glucose levels
- Increased gluconeogenesis
- Increased lipolysis
- Increased protein catabolism
- Decreased protein synthesis
- Decreased antibody formation
- Suppressed inflammatory response
How is cortisol regulated?
- Hypothalamus secretes corticotropin-releasing hormone
- Anterior pituitary secretes adrenocorticotropic hormone
- Low levels of plasma cortisol promote ACTH release
- High levels of plasma cortisol inhibit ACTH
What is the reference range of total cortisol?
- 8 AM: 5-23 micro-gram/dL
- 4 PM: 3-16 micro-gram/dL
What is the clinical significance of hypercortisolism?
- Primary hypercortisolism: adrenal adenoma or carcinoma, exogenous administration of cortisol, Cushing syndrome
- Secondary hypercortisolism: excessive production of ACTH due to pituitary tumor, ectopic production of ACTH by nonendocrine tumor, Cushing disease
What is the clinical significance of hypocortisolism?
- Primary hypocortisolism: atrophy of adrenal gland, autoimmune disease, tuberculosis, prolonged high-dosage cortisol therapy
- Secondary hypocortisolism: pituitary hypofunction
Name the inner portion of the adrenal gland
How are catecholamines synthesized?
Synthesized from tyrosine by chromaffin cells of the adrenal medulla, brain, and sympathetic neurons
Name the hormones that are included in catecholamines
What hormone mobilizes energy stores by converting glycogen to glucose, which allows the voluntary muscles to have greater work output?
What hormone functions as a neurotransmitter affecting the vascular smooth muscle and heart and released primarily by the potganglionic sympathetic nerves?
What hormone functions as a neurotransmitter in the brain affecting the vascular system?
What are epinephrine and norepinephrine metabolized into and what is the final product?
- Metabolized into metanephrine and normetanephrine
- Final end product vanillylmandelic acid (VMA)
What are increased levels of epinephrine and norepinephrine associated with?
What is a malignant tumor of the adrenal medulla that occurs in children?
What does the neuroblastoma tumor produce?
Produces epinephrine, norepinephrine, and dopamine
What is the end product of dopamine metabolism?
Homovanillic acid (HVA)
What clinical condition is characterized by:
Increased HVA urinary excretion
Increased VMA urinary excretion