(Ill) A thin rod of length carries a total charge Qdistributed uniformly along its length. See Fig. 21-67.Determine the electric fieldalong the axis of the rod starting vat one endthat is, find E(x) u----p---- ^for x > 0 in Fig. 21-67.
Chapter 9: Water and Minerals Friday, April 1, 2016 11:03 AM Water o Life cannot exist without water. o Water is a solvent for the chemicals in the body, allowing chemical reactions to take place. o Water makes up 50-70% of the body's weight. o Cannot survive long without water. Fluid Components o Intracellular Fluid: Water inside the cell o Extracellular Fluid: Water outside the cell o Water can diffuse between compartments. o Fluid Control o Ions control the movement of water between the intracellular and extracellular compartments o Ions are minerals with an electrical charge. They are also called electrolytes. o Osmosis: The movement of water across a semipermeable membrane. o Functions of Water o Solvent for chemical reactions within the body o Helps regulate temperature with sweat o Helps remove waste products Waste products dissolves into water o Cushions and lubricates Knees, joints, saliva, bile BalancingWater o Water isn't stored in the body. o Water balance is precisely by the nervous, endocrine, digestive, and urinary system Water Deficiency o 1-2% water loss - Thirst mechanism occurs o How do we conserve water Antidiuretic Hormone (ADH) Released by the pituitary gland Communicates with the kidney to conserve water. Aldosterone Released from the adrenal gland when blood volume decreases. Communicates with kidneys to conserve water and salt. o When Thirst is Ignored: 4% water loss - Muscles lose strength and endurance 10-12% water loss - Heat tolerance is decreased Become nauseous, confused, dizzy 20% water loss - A coma and perhaps death. o Can thirst be ignored Athletes - Weigh before and after Sick Children Older people Infants Over Consumption of Water o Too much in a short period of time leads to water intoxication or poison o Dilutes sodium levels - Hyponatremia Symptoms: Nausea Confusion Vomiting Headaches Muscle Weakness Convulsions Minerals o Major minerals: > 100 mg a day o Trace minerals: < 100 mg a day o Bioavailability: How much we take in Depends on: How much is in the food Our ability to absorb it The amount in a food doesn’t generally reflect the bioavailability. Minerals from plants: Depends on the soil it's grown in May be bound by dietary fibers and other molecules Minerals from animal sources: Are not as dependent on soil conditions Absorbed better than plant sources because of fewer binders and fibers o Mineral binders: Oxalates: Found in spinach; binds calcium Phytates: Found in grains; binds calcium, iron, zinc, others. Mineral-Mineral Interactions: Calcium-Iron; Zinc-Copper Vitamin-Mineral Interactions: Vitamin C: Improves iron absorption Vitamin D: Improves calcium absorption Mineral Toxicity o Minerals can be toxic in high levels, especially trace minerals o Not a problem when food is the source, but can be from mineral supplements Major Minerals o Calcium, Phosphorus, Potassium, Sulfur, Sodium, Chloride, and Magnesium. Calcium o Most abundant mineral in the body. o 99% of the calcium in the body is in the bones. Integral rolein the bone structure. Storehouse for calcium in the blood. o Adults absorb about 25% of the calcium in foods eaten. o Increase in infants and during pregnancy (Up to 60%) o Serum Calcium Functions: Regulates transport of ions across the cell membrane Also important in nerve transmission Helps maintain blood pressure Essential for muscle contractions Essential for secretion of hormones, enzymes, neurotransmitters, etc. Essential for blood clotting o Possible Health Benefits/Risks: Certain cancers and kidney stones Hypertension, high cholesterol, obesity o Osteoporosis: Decreased bone mass related to aging, genetic background, and poor diet. Leads to 1.5 million bone fractures per year in the U.S. Occurs in women and men Bone Density: Reaches a peak in the twenties Levels off in the thirties Lose after forty. It's important to build up bone density while you are young. Maintain Bone Density: Adequate amount of calcium and vitamin D in your diet Exercising Estrogen o Calcium in Foods AI: 1000-1200 mg per day Foods: Dairy Breads, rolls Leafy greens Calcium fortified products Supplements UL: 2500 mg per day Sodium o Absorb about 100% of sodium consumed o 30-40% found in the bones o The major positive ion found in the extracellular fluid o Functions: Fluid balance between compartments Nerve impulse conduction Absorption of glucose o Deficiency: Excessive perspiration Vomiting Diarrhea Leads to muscle cramps, nausea, dizziness, coma o Sensitivity: For most people, the body will readjust to higher sodium intake by increasing urine output. 10-15% of people have a sodium sensitivity High sodium intake leads to increased blood pressure. UL: 2300 mg per day Chloride o An ion of chlorine o Major negative ion for extracellular fluid o Used in producing stomach acids (HCl) and during immune response of white blood cells. Potassium o Major positive ion in intracellular fluid compartment. 95% of body's potassium o Important in fluid balance and nerve impulse transmission o Increasing Potassium is associated with lower blood pressure. o Increased risk of deficiency: People on diuretics to treat high blood pressure Alcoholics Certain Eating disorders Can lead to heart failure Too much - due to kidney failure, can stop heart. o AI: 4700 mg per day o Foods: Unprocessed Foods Rich Sources: Potatoes, plums, avocados, bananas, cantaloupe, honeydew melon, raisins Leafy greens Trace Minerals o Iron, Zinc, Selenium, Iodine, Copper, Chromium, Fluoride, etc. o All are toxic in excess. Iron o In every cell of the body o Absorb about 18% of that present in food. o Most iron associated with hemoglobin (RBC) and myoglobin (Muscle) o When RBC dies, iron is recycled. We lose very little, except during bleeding o Heme-iron is more readily absorbed than non-heme iron. o Vitamin C (75 mg) - enhances absorption of non-heme iron o Tannins in tea and phytates in grain inhibit iron absorption o Sources of heme-iron Organ meat Lamb/Mutton Pork Fish o Sources of non-heme iron Nuts Raisins Beans o Iron Deficiency Anemia: Decreased oxygen-carrying capacity of the blood. Lower number of RBC Less oxygen to the cells Affects 30% of the world population 1/2 of which is due to low iron Neurological dysfunction called Pica Eating weird things (ice, clay, dirt) Low iron associated anemia Impaired physical and mental activity Fatigue, loss of appetite Decreased learning ability Decreased attention span o Iron toxicity Hemochromatosis: A genetic condition characterized with bronzing of the skin. Associated with an increase of iron absorption. Iron builds up in the blood and liver, which can eventually lead to organ damage, especially the liver and heart. o Avoiding too much Iron UL: 45 mg a day Stomach irritation, toxicity can be life-threatening. Zinc o About 40% of dietary zinc is absorbed. o Zinc is a cofactor for up to 200 different enzymes o Functions: Growth Wound healing Sexual maturity Taste perception Immune system, indirect antioxidant o Sources: Oysters Beef Lamb Total (cereal) Chicken Clam High protein diets rich in animal sources are high in zinc. o Zinc Deficiency First recognized in the 1960s in boys from the middle east Diet low in animal protein, exclusive use of unleavened bread. Symptoms: Acne like rash Diarrhea Lack of appetite Delayed wound healing Impaired immunity Reduced sense of taste and smell Hair loss o Getting Enough Zinc RDA for men is 11 mg, women is 8 mg. Average American consumes about 10-14 mg/day Absorption depends on body needs. Phytic acid binds to zinc and limits availability High calcium intake decreases zinc absorption. Zinc competes with iron and copper for absorption. o Avoiding too much Zinc UL: 40 mg Excess interferes with copper metabolism Toxicity can occur from supplementation or over consumption of zinc-fortified foods. Intake greater than 100 mg results in diarrhea, cramps, nausea, vomiting, etc. Selenium o Indirect antioxidant, works with vitamin E to help protect cell membranes from oxidizing agents. o Binds to enzymes to protect against oxidation. o May have anticancer properties. o Selenium Deficiency Found in certain areas of China People developed characteristics muscle and heart problems associated with inadequate intake. o RDA: 55 micrograms/day o UL: 400 micrograms/day (hair loss) o Foods: Fish Eggs Shellfish Grains Seeds grown in soils containing selenium Iodide o Ion of iodine o Used in the production thyroid hormone o Thyroid hormone helps regulate metabolic rate, and promotes growth and development. o Iodide Deficiency Cells of the thyroid enlarge in attempt to trap more iodine. Called Goiter. People are sluggish and gain weight. During pregnancy, deficiency can cause extreme and irreversible mental and physical retardation of developing baby. Can be reversed within the first six months of pregnancy o RDA & DV: 150 micrograms o Most Americans consume more than the RDA o Found mostly in iodized salt. o Too much Iodide: UL: 1.1 mg High amounts can inhibit thyroid hormone synthesis. Copper o 12-75% of copper in the diet is absorbed. o Involvedin the metabolism of iron by functioning in the formation of hemoglobin and transport iron. o Also involved in the formation of connective tissue. o Is a cofactor for antioxidant enzymes. o Getting Enough Copper: Sources include liver, legumes, seeds, whole grain bread, cereals, cocoa Form found in supplements is not readily absorbed. Absorption is highly variable. Higher intakes associated with lower absorption efficiency. Phytates, fiber, excess zinc and iron supplements interfere with absorption. AI: 1 mg for women, 1.6 mg for men. o Avoiding too much Copper: 10 mg can cause toxicity. Symptoms include GI distress, vomiting blood, tarry feces, damage to liver and kidneys. Toxicity only occurs with supplementation. o Wilson's disease: A genetic disorder that results in accumulation of copper in the tissues. Characterized by damage to the liver, nervous system, and other organs. Dietary Supplements o Regulated by the Dietary Supplement Health and Education Act established in 1994 (DSHEA) o Established by Congress o Gives FDA the authority to regulate the,. o Established the office of Dietary Supplements under the NIH o DSHEA definition: Vitamin, mineral, herb or another botanical amino acid. A dietary substance to supplement the diet which could be an extract or a combination of the first four ingredients in the previous definition. Dietary supplements can be sold without proof that they are safe and effective Supplement makers ca make broad "structure or function" claims about their products. Cannot claim to prevent, treat, or cure a disease. o Should you take a supplement Evidence to support the widespread use of multivitamin and mineral supplements is mixed. Little risk of harm from consuming a balanced multivitamin Most studies indicate no discernible advantage. NIH concluded that the present evidence is insufficientto recommend for or against. Only a few studies of vitamin and mineral supplementsprevent deficiencies or chronic disease. High doses of one nutrient can affect absorption or metabolism of other nutrients. Some supplements can interfere with medications. The safest and healthiest way to ensure nutrient adequacy is… Think food first Fortified foods that can help fill gaps If supplement use is desired, educate yourself and discuss the choice with your physician or registered dietician Which Supplements to Choose Choose nationally recognized brand Ensure not to exceed the UL from supplements and fortified foods. Look for the United States Pharmacopeial Convention (USP) seal] Homeopathic Remedies Regulated by the FDA FDA doesn’t evaluate the remedies for safety or effectiveness Little evidence to support homeopathy as an effective treatment for any specific condition Must contain active ingredients that are listed in the Homeopathic Pharmacopeia of the United States (HPUS)