nutri sci final study guide

nutri sci final study guide - Bone Health Bone is living...

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Bone Health Bone is living tissue Bone growth ends by age 35 Osteoblasts - build protein matrix and minerals Osteoclasts - dissolve bone matrix and release minerals into the bloodstream __________% of the body’s calcium is in the blood If blood calcium is low , parathyroid hormone is released from the parathyroid gland Parathyroid hormone acts on the kidney to activate vitamin D and increase intestinal absorption of calcium Parathyroid hormone acts on the osteoclasts in bone to release calcium into the bloodstream, which increases blood calcium levels If blood calcium is high , calcitonin is released from the thyroid gland Calcitonin stimulates the osteoblasts to take up more calcium and form new bone tissue, so blood calcium is lowered Phytochemicals are produced by plants 128/156 studies show that fruits and vegetables have a protective effect against cancer Phytochemicals may prevent cancer by acting as anti-oxidants o Some may detoxify carcinogens by blocking initiation o Some might lower cholesterol by preventing cholesterol synthesis in the body o Some might exert weak estrogen like effects and thereby protect against bone loss (genistein) Dietary carcinogens include: nitrites , pickling , mold Apoptosis -programmed cell death 3 Stage Model of Carcinogenesis o Initiation- DNA damage o Promotion- more DNA damage, takes the cell from initiated cancerous o Progression- a tumor is produced Anti-carcinogens - chemicals that stop the development of cancer Detoxification enzymes - from grapefruit juice, sulforaphane in broccoli and cabbage , and phenols in fruits and vegetables Genistein - found in soybeans ; chemically similar to estrogen and is able to bind to estrogen receptors, preventing estrogen from binding to its own receptors; blockades estrogen receptors o Also inhibits angiogenesis , growth of new blood supply to new and growing tumor cells Lignans - made from the insoluble dietary fiber lignin by gut bacteria; lowers blood levels of estrogen Indoles - found in broccoli and cabbage, which lowers the production of the estrogen precursor
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Tumor growth in rats slowed when given these phytochemicals o Limonene - from citrus o Geraniol -from hops o Beta-ionone - from raspberries and ginger Roles of phytochemicals in plants o Synthesize chemicals to kill bacteria and fungi o Produces bad tasting and toxic chemicals to keep it from being eaten o Must attract insects to carry pollen o Plants have a greater chemical diversity than animals The US average intake of vegetables is 1.5 servings a day o For fruits its less than 1 serving per day o The recommended intake for fruits and vegetables is 2-5 servings/day Pregnancy Two types of growth o Hyperplasia - growth in the number of cells o Hypertrophy - growth in the size of cells Teratogens are most dangerous during the 1 st Trimester During the third trimester, the fetus grows from 2-3 pounds at eh beginning to 7-8
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nutri sci final study guide - Bone Health Bone is living...

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