Water and Major Minerals. b Water is an essential nutrient. b Can only last a few days without it. b...

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Water and Major MineralsWater and Major Minerals

WaterWater andand MajorMajor MineralsMinerals

Water is an essential nutrient.Water is an essential nutrient.Can only last a few days without it.Can only last a few days without it.The minerals maintain adequateThe minerals maintain adequate

distribution of water in the body.distribution of water in the body.Water is inside and outside of Water is inside and outside of

every cell in the body.every cell in the body.

Water’sWater’s functionfunction inin thethe bodybody..

Carries nutrients to and waste Carries nutrients to and waste products from the cells.products from the cells.

Serves as a solvent and takes Serves as a solvent and takes part in metabolic reactions.part in metabolic reactions.

Acts as a lubricant around Acts as a lubricant around joints.joints.

Regulates body temp and blood Regulates body temp and blood volume.volume.

Figure 12-4Page 402

Water Dissolves Salts and Follows Electrolytes

Na+O H

-ClNa+

The structural arrangement of the two hydrogen atoms and one oxygenatom enables water to dissolve salts. Water’s role as a solvent is one ofits most valuable characteristics.

WaterWater homeostasishomeostasis

60 % of adult weight is water.60 % of adult weight is water.Hypothalamus regulates water Hypothalamus regulates water

intake by stimulating thirst.intake by stimulating thirst.Dehydration: deprivation or Dehydration: deprivation or

excessive loss of fluid.excessive loss of fluid.Water intoxication: kidney Water intoxication: kidney

failure.failure.

Table 12-1Page 397

WaterWater sourcessources..

Beverages in the diet.Beverages in the diet.Water content of food, up to Water content of food, up to

90%.90%.Metabolic water.Metabolic water.These 3 sources average 2 1/2 These 3 sources average 2 1/2

Table 12-2Page 397

WaterWater losseslosses

Body must excrete 500 ml every Body must excrete 500 ml every day to discard waste products.day to discard waste products.

Water lost as vapor from lungs Water lost as vapor from lungs and sweat from skin; 1/2 of and sweat from skin; 1/2 of loss.loss.

Some water lost in feces.Some water lost in feces.Average loss is 2 1/2 L.Average loss is 2 1/2 L.

Table 12-3Page 398

WaterWater andand blood volumeblood volume

Water maintains blood volume.Water maintains blood volume.Kidneys regulate blood volume Kidneys regulate blood volume

by releasing or retaining water.by releasing or retaining water.Hypothalamus activates Hypothalamus activates

pituitary gland to secrete ADH pituitary gland to secrete ADH to retain water by kidneys and to retain water by kidneys and signal thirst.signal thirst.

WaterWater andand bloodblood pressurepressure

Kidneys release enzyme renin Kidneys release enzyme renin which causes kidneys to which causes kidneys to reabsorb sodium; water follows reabsorb sodium; water follows sodium.sodium.

Renin activates angiotensin Renin activates angiotensin which constricts blood vessels.which constricts blood vessels.

Angiotensin activates Angiotensin activates aldosterone which retains more aldosterone which retains more Na+ and waterNa+ and water

Water distribution in body.Water distribution in body.

2/3 inside and 1/3 outside cells.2/3 inside and 1/3 outside cells.Mineral salts dissolved in water Mineral salts dissolved in water

become cations (+) or anions (-).become cations (+) or anions (-).Electrolytes are mineral salts.Electrolytes are mineral salts.Electrolytes attract water and Electrolytes attract water and

help to maintain homeostasis.help to maintain homeostasis.

Figure 12-1Page 397

One Cell and Its Associated Fluids

Fluid between thecells (intercellularor interstitial)

Nucleus

Cellmembrane

Fluid within thecell (intracellular)

Blood vessel

Fluid (plasma) within the bloodvessels (intravascular)

Electrolyte distributionElectrolyte distribution

Sodium and chloride are outside Sodium and chloride are outside the cells.the cells.

Potassium, magnesium, sulfate, Potassium, magnesium, sulfate, phosphate are inside the cells.phosphate are inside the cells.

Water follows electrolytes across Water follows electrolytes across the cell membranes; osmosis.the cell membranes; osmosis.

Electrolytes must be = in charge.Electrolytes must be = in charge.

Table 12-4Page 402

Figure 12-5Page 403

Osmosis

Water can flow both waysacross the divider, but has agreater tendency to move fromside A to side B, where thereis a greater concentration ofsolute. The volume of waterbecomes greater on side B,and the concentrations onside A and B become equal.

32 Now additional solute isadded to side B. Solute cannotflow across the divider (in thecase of a cell, its membrane).23

1 With equal numbers of soluteparticles on both sides, theconcentrations are equal,and the tendency of water tomove in either direction isabout the same.

In-text Figure Page 403When sprinkled with salt, vegetables “sweat” because water moves

toward the higher concentration of salt outside the eggplant.

Fluid and Electrolyte Fluid and Electrolyte imbalance.imbalance.

Vomiting, diarrhea, profuse Vomiting, diarrhea, profuse sweating, burns, draining sweating, burns, draining wounds may cause imbalance.wounds may cause imbalance.

Sodium and chloride easily Sodium and chloride easily lost.lost.

Electrolytes and fluids must be Electrolytes and fluids must be replaced when imbalance replaced when imbalance occurs.occurs.

Acid-base balanceAcid-base balance

Normal pH is 7.35 to 7.45 for Normal pH is 7.35 to 7.45 for blood.blood.

Proteins are damaged beyond Proteins are damaged beyond normal range; body can’t function.normal range; body can’t function.

Buffers in blood, rate of respiration Buffers in blood, rate of respiration and regulation by kidneys maintain and regulation by kidneys maintain acid-base balance.acid-base balance.

Figure 12-6Page 405

The pH Scale

pH neutral

Acidic

Normal and abnormalpH ranges of blood

pH’s of commonsubstances

Acidosis

Normal

Alkalosis

Battery acid

Gastric juiceLemon juice

Vinegar

Concentrated lye

Household ammonia

Baking soda

Pancreatic juice

WaterBlood

MilkUrine

Coffee

Orange juice

Major mineralsMajor minerals

Inorganic elements; can not Inorganic elements; can not be destroyed in food prep.be destroyed in food prep.

May be bound by food May be bound by food compounds or interact with compounds or interact with other minerals.other minerals.

May not be absorbed.May not be absorbed.All have upper levels of intake.All have upper levels of intake.

Sodium functionsSodium functions

Principal cation and regulator of Principal cation and regulator of volume in extracellular fluid.volume in extracellular fluid.

Essential for nerve Essential for nerve transmission, muscle transmission, muscle contraction, acid-base balance.contraction, acid-base balance.

Kidneys filter out excess.Kidneys filter out excess.

Sodium and healthSodium and health

Need a minimum of 500 mg Need a minimum of 500 mg Na+.Na+.

Salt sensitive individuals may Salt sensitive individuals may benefit from Na+ restriction.benefit from Na+ restriction.

Hyponatremia: low blood Na+.Hyponatremia: low blood Na+.Na+ toxicity: edema and Htn.Na+ toxicity: edema and Htn.Processed foods are high in Processed foods are high in

Na+.Na+.

Figure 12-8Page 409

What Processing Does to the Sodium and Potassium Contents of Foods

Milk (whole)

Unprocessed

Peach pie

Processed

Canned,cream corn

Instantchocolatepudding

Oat cereal

Freshpeaches

Chipped beef

Vegetables

Fresh corn

Roast beef

Fruits

Rolled oats

Grains

Sodium

Potassium

Chloride functions.Chloride functions.

Major anion in extracellular Major anion in extracellular fluid.fluid.

Part of hydrochloric acid.Part of hydrochloric acid.Maintains fluid and Maintains fluid and

electrolyte balance. electrolyte balance.

Chloride and healthChloride and health

Adequate intake for adults is Adequate intake for adults is 2300 mg/day for 19-50 year olds2300 mg/day for 19-50 year olds

Need for Cl decreases with ageNeed for Cl decreases with ageDeficiency: rareDeficiency: rareToxicity may occur due to Toxicity may occur due to

dehydration.dehydration. Processed foods are high in NaClProcessed foods are high in NaCl

Potassium functionPotassium function

Principal cation inside cells.Principal cation inside cells.High intake appears to reduce High intake appears to reduce

high blood pressure.high blood pressure.Potassium and sodium trade Potassium and sodium trade

places across cell membranes places across cell membranes during nerve transmission during nerve transmission and muscle contraction.and muscle contraction.

Potassium and healthPotassium and health

Adequate intake for adults is Adequate intake for adults is 4700 mg/day.4700 mg/day.

Best source is fresh fruits and Best source is fresh fruits and veg.veg.

K+ deficiency is most common K+ deficiency is most common electrolyte imbalance; weakness.electrolyte imbalance; weakness.

Caused by diuretics, dehydration,Caused by diuretics, dehydration,

DM acidosis, vomiting, steroids.DM acidosis, vomiting, steroids.

In-text Figure Page 411

Fresh foods, especially fruitsand vegetables, providepotassium in abundance.

Calcium functionCalcium function

99% is found in bones and 99% is found in bones and teeth.teeth.

Cation regulates muscle Cation regulates muscle contraction, blood clotting, contraction, blood clotting, nerve transmission, secretion nerve transmission, secretion of hormones, activation of of hormones, activation of enzymes and regulates blood enzymes and regulates blood pressure.pressure.

Calcium and healthCalcium and health

Recommendations for bone Recommendations for bone healthhealth

1000 mg for 19-50 years 1000 mg for 19-50 years oldold

1200 mg for 50 + years.1200 mg for 50 + years.Calcium taken from bones Calcium taken from bones

when blood calcium is low.when blood calcium is low.

Figure 12-13Page 417

Phases of Bone Development throughout Life

Bonedensity

Bone lossActive growth

Peak bone mass

Figure H12-3Page 431

Bone Losses over Time Compared

Woman B had less bonemass starting out and sosuffered ill effects frombone loss later on.

Age 30

Danger zone

Menopause

Woman A entered adulthoodwith enough calcium in herbones to last a lifetime.

Age 60

Osteoporosis

Maintaining Blood Calcium from the Diet and from the Bones

With an adequate intake ofcalcium-rich food, bloodcalcium remains normal...

With a dietary deficiency,blood calcium still remainsnormal...

...because bones give up calcium to the blood. The result is weak, osteoporotic bones.

...and bones deposit calcium. The result is strong, dense bones.

Calcium sourcesCalcium sources

Milk products, tofu, sardines Milk products, tofu, sardines with bones, bok choy, black with bones, bok choy, black strap molasses, fortified strap molasses, fortified orange juice, corn tortillas, orange juice, corn tortillas, broccoli broccoli

Milk and milk products are rightlyfamous for their calcium contents.

Bioavailability of Calcium from Selected Foods

Cauliflower, watercress,brussels sprouts, rutabaga,kale, mustard greens, bokchoy, broccoli, turnip greens

>50%absorbed

>30%absorbed

>20%absorbed

>5%absorbed

Milk, calcium-fortified soymilk, calcium-set tofu,cheese, yogurt, calcium-fortifiedfoods and beverages

Almonds, sesame seeds,pinto beans, sweet potatoes

Spinach, rhubarb, Swisschard

Phosphorus functionPhosphorus function

Part of bones and teethPart of bones and teeth Found in all body cells; used as a Found in all body cells; used as a

bufferbuffer Part of DNA and RNAPart of DNA and RNA Part of ATP, the energy moleculePart of ATP, the energy molecule Activates enzymes and B vitaminsActivates enzymes and B vitamins Part of phospholipids, part of cell Part of phospholipids, part of cell

membranes, transports other lipidsmembranes, transports other lipids

Phosphorus and healthPhosphorus and health

RDA: 700 mg per day for adultsRDA: 700 mg per day for adults Sources: meats, milk products, Sources: meats, milk products,

legumes, soda with phosphoric acidlegumes, soda with phosphoric acid Dietary deficiency unknownDietary deficiency unknown High phosphorus, low calcium blood High phosphorus, low calcium blood

levels will lead to bone loss in levels will lead to bone loss in people with kidney failure.people with kidney failure.

Magnesium functionMagnesium function

Over half of magnesium is found in Over half of magnesium is found in the bones and dental enamelthe bones and dental enamel

Found in muscles and soft tissueFound in muscles and soft tissue Necessary for body’s production of Necessary for body’s production of

protein and for energy metabolismprotein and for energy metabolism Part of many enzymesPart of many enzymes Inhibits muscle contraction and Inhibits muscle contraction and

blood clotting; calcium promotes blood clotting; calcium promotes thesethese

Magnesium and healthMagnesium and health

RDA: 400 mg per day for men RDA: 400 mg per day for men RDA: 310 mg per day for womenRDA: 310 mg per day for women Sources: legumes, seeds, nuts, leafy Sources: legumes, seeds, nuts, leafy

green vegetablesgreen vegetables Deficiency: tetany; impaired central Deficiency: tetany; impaired central

nervous system function; constricted nervous system function; constricted circulatory system, may cause Htncirculatory system, may cause Htn

Toxicity: rare; fatal; from supplements Toxicity: rare; fatal; from supplements

Sulfur functionSulfur function

Found in essential nutrients such Found in essential nutrients such as vitamins and amino acidsas vitamins and amino acids

Sulfur bonds shape protein Sulfur bonds shape protein molecules and provide stability to molecules and provide stability to the protein structurethe protein structure

Skin, hair, nails contain sulfur Skin, hair, nails contain sulfur containing protein moleculescontaining protein molecules

Sulfur and healthSulfur and health

No RDA for sulfurNo RDA for sulfur No known deficiency; diet would No known deficiency; diet would

have to be deficient in protein rich have to be deficient in protein rich foodsfoods

Sources: meats, eggs, milk, Sources: meats, eggs, milk, legumes, nutslegumes, nuts

Click to view animation.

Bacteriophage studies

Animation

Figure 12-2Page 400

A Nephron, One of the Kidney’s Many Functioning Units

Renal artery

Kidney

Pelvis

Ureter

Bladder

Kidney, sectionedto show locationof nephrons

A nephron (a working unit of the kidney).Each kidney contains over one million nephrons.

The tubule passes wastematerials on to the bladder.

Renal vein

Blood flows into the glomerulus,and some of its fluid, withdissolved substances, isabsorbed into the tubule.

Then the fluid and substancesneeded by the body are returnedto the blood in vessels alongsidethe tubule.

To the bladder

Capillariesof glomerulus

Glomerulus

To the body

Blood vessel

Tubule

The cleansing of blood in the nephron is roughly analogousto the way you might clean your car. First you remove all yourpossessions and trash so that the car can be vacuumed.(1)Then you put back in the car what you want to keep(2) andthrow away the trash. (3)

Figure 12-3Page 401

How the Body Regulates Blood Volume

Aldosterone

Angiotensin causesthe blood vesselsto constrict, raisingpressure.

The hypothalamus respondsto high salt concentrationsin the blood by stimulating

the pituitary gland.

Renin initiates the activation of the protein angio-

tensinogen to angiotensin.

Angiotensin signalsthe adrenal gland to secrete aldo-sterone.

BrainKidneys

Aldosterone and ADH signal the kidneys to retain sodium and water,respectively, thus increasing blood volume.

The kidneys respond toreduced blood flow byreleasing the enzyme

renin.

The pituitary glandreleases antidiuretic

hormone (ADH).

Angiotensin

In-text Figure Page 403When immersed in water, raisins get plump because water moves

toward the higher concentration of sugar inside the raisins.

Physically active people must rememberto replace their body fluids.

Figure 12-7Page 406

Minerals in a 60-kilogram (132-pound) Human Body

TRACE MINERALSThere are more than a dozen trace minerals,although only six are shown here.

Amount (g)

MAJOR MINERALSThe major minerals are those present in amountslarger than 5 g (a teaspoon). A pound is about454 g; thus only calcium and phosphorus appearin amounts larger than a pound.

Fresh herbs add flavor to a recipewithout adding salt.

Figure 12-9Page 412

Potassium in Selected Foods

Fruits

Milk and milk products

Legumes, nuts, seeds

Best sources per kcalorie

Breads and cereals

Vegetables

POTASSIUMFresh fruits (purple), vegetables(green), legumes (brown), andmeats (red) contribute potassiumto the diet.

Food Serving size (kcalories)

Milligrams

The AI for potassium is 4700 mgper day.

0 200 400 600 800

Calcium Balance

Parathormonestimulates theactivation ofvitamin D.

Rising blood calciumsignals the thyroidgland to secretecalcitonin.

Calcitonin limitscalcium absorptionin the intestines.

Calcitonininhibits theactivationof vitamin D.

Parathyroid(embeddedin the thyroid)

Falling blood calciumsignals the parathyroidglands to secreteparathormone.

Vitamin D

Vitamin DActivation

Vitamin Denhances calciumabsorption inthe intestines.

All these actions raise bloodcalcium levels, which inhibitsparathormone secretion.

All these actions lower bloodcalcium levels, which inhibitscalcitonin secretion.

Vitamin D andparathormonestimulate calciumreabsorptionin the kidneys.

Vitamin D andparathormonestimulateosteoclast cells tobreak down bone,releasing calciuminto the blood.

Calcitoninprevents calciumreabsorptionin the kidneys.

Calcitonin inhibitsosteoclast cellsfrom breakingdown bone,preventing therelease of calcium.

Intestines

Kidneys

CalcitoninParathormone

Thyroid

Calcium in Selected Foods

Fruits

Breads and cereals

Vegetables

CALCIUMAs in the riboflavin figure, milk and milk products (white)dominate the calcium figure. Most people need at least threeselections from the milk group to meet recommendations.a Values based on products containing added calcium salts;the calcium in 1⁄2 c soybeans is about 1⁄3 as much as in1⁄2 c tofu. b If bones are discarded, calcium declines dramatically.

Food Serving size (kcalories)Milligrams

AI formen

19–50

AI formen51+

AI forwomen19–50

AI forwomen

Phosphorus in Selected Foods

Fruits

Breads and cereals

Vegetables

PHOSPHORUSProtein-rich sources, such asmilk (white), meats (red), andlegumes (brown), provideabundant phosphorus as well.

RDAfor

adults

Magnesium in Selected Foods

Fruits

Breads and cereals

Vegetables

MAGNESIUMLegumes (brown) are a richsource of magnesium.

RDA forwomen19-31

RDA formen19-30

Osteoporosis andCalcium

Healthy and Osteoporotic Trabecular Bones

Electron micrograph of trabecular boneaffected by osteoporosis.

Electron micrograph of healthytrabecular bone.

Loss of Height in a Woman Caused by Osteoporosis

80 years old

6 inches lost

50 years old

Table H12-1Page 430

Table H12-2Page 430

Strength training helps tobuild strong bones.

Water and Major Minerals. b Water is an essential nutrient. b Can only last a few days without it. b...

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