ENDOCRINE SYSTEMI. Introduction: Endocrine Glands are ductless glands that secrete hormones into the blood; controlled by the Hypothalamus. II. GlandsA. Pituitary = Hypophysis: hangs from the hypothalamus of the diencephalon 1. Adenohypophysis = anterior lobe aka anterior pituitarya. Growth hormone (GH) - regulates mitosis & growth of body cells b. Thyroid stimulating hormone (TSH) – controls thyroid activity c. Adrenocorticotropic hormone (ACTH) - controls activity of adrenal cortex d. Follicle stimulating hormone (FSH) – stimulates oogenesis (egg production) and spermatogenesis (Sperm production) e. Luteinizing hormone (LH) - Stimulates release of male & female sex hormones f. Prolactin (PRL) – milk productiong. Melanocyte releasing hormone (MSH)- stimulate melanin production 2. Neurohypophysis = Posterior Lobe = Posterior Pituitary: a. Oxytocin – i. causes uterine contractions during labor ii. Milk release during suckling. iii. Smooth muscle to contract in males to cause ejaculationb. Antidiuretic hormone (ADH, Vasopressin) – inhibits urine formation B. Thyroid: bilobed, just below larynx. 1. Thyroid Hormone (TH) - it increases cellular activity in skeletal, reproductive & nervous systems 2. Calcitonin - is released in response to increased blood calcium levels. Calcitonin decreases blood calcium by stimulating the deposition of calcium into bone. C. Parathyroids: 4 masses on back of thyroid. They release parathyroid hormone (PTH) in response to low calcium levels. - Parathyroid hormone (PTH) function: increase blood calcium levels by stimulating the removal of calcium from bone. D. Pancreas: Hormones are secreted from Pancreatic Islets 1. Beta Cells: secrete Insulin in response to high levels of glucose. Insulin decreases blood sugar. 2. Alpha Cells: secrete Glucagon in response to low levels of glucose. Glucagon increases blood sugar. E. Adrenal gland: atop kidneys; 2 areas: Cortex and Medulla1. Cortex - secretes steroids = Corticosteroids (in response to ACTH); 3 types a. Mineralocorticoids – regulate sodium and potassium levels; from Zona Glomerulosa b. Glucocorticoids – increases breakdown of fats and proteins to generate blood glucose = anti-stress; from Zona Fasciculata. c. Gonadocorticoids – produces sex hormones (normally very little of Estrogen, Progesterone, and Testosterone). May affect the onset of puberty, pubis and axillary hair development and sex drive.From Zona Reticularis. 2. Medulla - secretes Epinephrine (adrenaline) & Norepinephrine (noradrenalin), prepares the body for “fight or flight” F. Gonads 1. Testes - testosterone 2. Ovaries - estrogen & progesterone G. Thymus: bilobed; located at tracheal bifurcation. The thymus secretes Thymosin. Which of the following hormones is responsible for sodium and potassium balance? a. Glucocorticoidb. Mineralocorticoid c. Parathyroid hormone (PTH) d. Calcitonin e. Thyroid hormone
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