Broken down into amino acids either oxidized to

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- broken down into amino acids, either oxidized to produce ATP or used to synthesize new proteins for body growth and repair (never stored), excess dietary acids are covered into glucose (gluconeogenesis) or triglycerides (lipogenesis). Insulinlike growth factors, thyroid hormones (T3 and T4), insulin, estrogen, and testosterone all stimulate protein synthesis. All-or-none rule - all amino acids necessary to make protein must be available or production will stop. Protein Catabolism - Amino acids are oxidized via Krebs cycle after deamination. Ammonia resulting from deamination is converted into urea in liver, passed into blood, and excreted in urine. Amino acids may be converted into glucose (gluconeogenesis), fatty acids, or ketone bodies. Protein anabolism - Protein synthesis is directed by DNA and utilizes cells’ RNA and ribosomes. Thermoregulation and the role of the hypothalamus. Thermoreceptors in the skin and hypothalamus send nerve impulses to the preoptic area and the heat-promoting center in the hypothalamus, and to hypothalamic neurosecretory cells that produce thyrotropin-releasing hormone (TRH). In response, the hypothalamus discharges nerve impulses and secretes TRH, which in turn stimulates thyrotrophs in the anterior pituitary to release thyroid-stimulating hormone (TSH). Nerve impulses from the hypothalamus and TSH then activate several effectors- vasoconstriction, release epinephrine&norepinephrine to increase cellular metabolism, shivering, thyroid hormones. Discriminate between fat soluble and water soluble vitamins Vitamins - Organic nutrients required in small amounts to maintain growth and normal metabolism. Fat-soluble vitamins - vitamins A, D, E, and K, are absorbed along with other dietary lipids in the small intestine and packaged into chylomicrons, require bile salts and some dietary lipids for adequate absorption, stored in hepatocytes. Water-soluble vitamins- B vitamins and vitamin C, dissolved in body fluids, not stored in body, excess intake eliminated in urine. Understand the role(s) of the following vitamins: A, B 1 , B 2 , B 12 , C, D, folic acid, K, niacin Vitamin A- Maintains general health and vigor of epithelial cells, Beta-carotene acts as antioxidant to inactivate free radicals, essential for formation of light-sensitive pigments in photoreceptors of retina, Aids in growth of bones and teeth by helping to regulate activity of osteoblasts and osteoclasts. Vitamin B1 (thiamine) - Acts as coenzyme for many different enzymes that break carbon-to-carbon bonds and are involved in carbohydrate metabolism of pyruvic acid to CO2 and H2O. Essential for synthesis of neurotransmitter acetylcholine. Vitamin B2 (riboflavin) - Component of certain coenzymes (for example, FAD and FMN) in carbohydrate and protein metabolism, especially in cells of eye, integument, mucosa of intestine, and blood. Vitamin B12 - Coenzyme necessary for red blood cell formation, formation of amino acid methionine, entrance of some amino acids into Krebs cycle, and manufacture of choline (used to synthesize acetylcholine). Vitamin C

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