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I. Introduction B. Adrenal Cortex

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I. Introduction B. Adrenal Cortex I. Introduction Adrenal Glands • suprarenal – they sit on top of the kidneys • each is composed of 2 distinct regions: A. Adrenal Medulla - the inner region - comprises 20% of the gland - secretes epinephrine and norepinephrine - derived from ectoderm B. Adrenal Cortex 1) Zona Glomerulosa (outermost region) - produces mineralocorticoids (aldosterone) • the outer region 2) Zona Fasiculata (middle region) - produces glucocorticoids (cortisol) as well as • comprises 80% of the gland estrogens and androgens • secretes corticosteroids 3) Zona Reticularis (innermost region) • derived from mesoderm - same function as zona fasiculata DHEA – dehydroepiandrosterone • an adrenal androgen in females • responsible for growth of pubic and axillary hair C. Pathologies Associated with Adrenal II. Mineralocorticoids (Aldosterone) Androgen Hypersecretion A. Functions 1.Adrenogenital Syndrome - promotes reabsorption of Na+ and - hypersecretion of androgens or estrogens secretion of K+ from the distal portion of the a) in the adult female: nephron..primary regulator of salt balance and extracellular volume - masculinization (i.e. hirsutism) -Similar (but less important) effect on salt b) in the female embryo: transport in colon, salivary glands, and - female pseudohermaphroditism sweat glands. c) in the adult male: - no effect d) in young boys: - precocious pseudopuberty 1 II. Mineralocorticoids (Aldosterone) C. Pathologies B. Regulation of Secretion 1. Hypersecretion 1. Renin Angiotensin a. primary hyperaldosteronism - Angiotensin II stimulates aldost. secretion - Conn’s syndrome 2. Potassium - usually due to a tumor on the gland + - high levels of K induce aldost. secretion - too much secretion of gland itself 3. ACTH –no direct role b. secondary hyperaldosteronism - default in renin angiotensin system - most common in atherosclerosis of renal arteries C. Pathologies III. Glucocorticoids (Cortisol) 1. Hypersecretion A. Metabolic Effects c. Symptoms - overall effect: increase plasma glucose levels, often at the expense of » hypernatremia proteins and fats »hypokalemia 1. Liver 2. Hyposecretion (defer to a. gluconeogenesis later) b. increase glucose output 2. Muscle III. Glucocorticoids (Cortisol) III. Glucocorticoids (Cortisol) A. Metabolic Effects A. Metabolic Effects - overall effect: increase plasma glucose 3. Fats levels, often at the expense of proteins and fats a. Increases lipolysis 2. Muscle b. Anti-insulin a. break down protein to c. Alters distribution.. provide substrate for gluconeo. b. Anti-insulin effect moon-faced…scapular hump. 2 Other Effects- Fetal Other Effects-Adults • Cortisol aids in maturation of the • Decreases Bone Mass lungs, especially with the production • Response to Stress (G.A.S) of surfactant • CNS Effects • Maturation of g.i. enzymes • Catecholamines • Signals partuition ?? Other Effects (cont.) Pharmacology • Suppresses the immune system by inhibiting cytokine release and antibody production. Compound Gluco.Effect Miner. Eff Cortisol 1 1 • Inhibits inflammation by decreasing leukocyte mobilization and migration. Prednisone 3-4 0.5 Dexamethazone 20 1 C. Regulation D. Pathologies - it’s a classic negative feedback system - low glucocorticoid levels cause the 1) Hypersecretion hypothalamus to secrete corticotropin - Cushing’s Syndrome releasing hormone (CRH) - caused by too much exogenous cortisol, - CRH and low glucocorticoid levels cause the too much ACTH, an adrenal tumor, or ACTH anterior pituitary to release ACTH secreting tumor - ACTH stimulates glucocorticoid production at the adrenal cortex – Symptoms » Proteolysis * Stress and hypoglycemia can also trigger the » Moon-faced and buffalo hump release of CRH 3 D. Pathologies CONT. 2) Hyposecretion a) Primary Adrenal Cortical Insufficiency - Addison’s Disease - due to autoimmuno destruction of the gland b) Secondary Adrenal Cortical Insufficiency - due to too little ACTH EICOSANOIDS Prostaglandin Nomenclature ARACHIDONIC ACID •3 Groups •PGA •PGE prostaglandins •PGF prostacyclins •Double Bonds leukotriens •Optical Isomer thromboxanes Prostaglandin Functions • Reproduction • Respiratory • Nervous • Immune • MANY OTHERS!! 4.
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