Overview of Endocrine Glands random notes

Overview of Endocrine Glands random notes - Overview of...

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Overview of Endocrine Glands While exocrine glands secrete substances into the external environment (skin, digestive tract lumen), endocrine glands secrete hormones into the interstitial fluid. Primary endocrine organs: Hypothalamus, pituitary, pineal, thyroid, parathyroid Thymus, adrenal, pancreas, gonads (testes/ovaries), placenta Secondary endocrine organs: Heart, liver, stomach, small intestine, kidney, skin Hypothalamus and Pituitary Glands Hypothalamus: Part of the brain with many functions Primary because it secretes many hormones Most hormones affect the pituitary, a small structure attached to hypothalamus by the infundibulum. Posterior pituitary / neurohypophesis: Contains neurons that originate in the hypothalamus Secrete ADH and oxytocin from different areas Called neurohormones Anterior pituitary / adenohypophysis: Secrete tropic hormones (regulate release of other hormones) Can be stimulating or inhibiting Anterior pituitary / adenohypophysis: Hormone release in anterior pituitary triggered by neurohormone released in hypothalamus. Hypothalamic-pituitary portal system: Neurosecretory cells in hypothalamus release tropic hormone into portal vein, causing tropic hormone release from pituitary into bloodstream, causing hormone release from another endocrine gland, which affects the target organ. Thyroid Gland Thyroid: secretes thyroid hormones T3 and T4. Levels are normally kept constant. Requires uptake of iodine to synthesize. T3, the activated form, increases metabolism: Increases Na+/K+ pump activity Increases mitochondria Increases oxidative phosphorylation enzymes à This causes increased body heat production and oxygen consumption Blood levels of T4 are negative feedback to maintain thyroid hormone at normal levels. Hypothyroidism Decreased production of T3 and T4 Often caused by autoimmune disease: Hashimoto's thyroiditis Many symptoms include fatigue, weight gain, rough hair or skin, cold intolerance, irritability. Blood test will reveal T4 levels are low and TSH levels are high. Treatment is by hormone replacement therapy in pill form. Hyperthyroidism Overproduction of T3 and T4
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Caused by: Graves disease (autoimmune disease that triggers activating sites on thyroid to create more hormone), benign tumors. Symptoms include irregular heartbeat, heat intolerance, nervousness, insomnia, weight loss. Treatments include: Lifetime thyroid-suppresion medication Taking radioactive iodine to kill the thyroid, then taking lifetime synthetic hormone pills Partial thyroidectomy to remove tumor Parathyroid Gland Parathyroid: secretes parathyroid hormone (PTH) to regulate blood calcium levels. Hyperparathyroidism
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This note was uploaded on 04/09/2010 for the course MCB 240 taught by Professor Meisami during the Spring '08 term at University of Illinois, Urbana Champaign.

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Overview of Endocrine Glands random notes - Overview of...

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