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Water and the Major Minerals Chapter 12. Water and the Body Fluids Water constitutes majority of body weight – Body composition Females Obese people Elderly.

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Presentation on theme: "Water and the Major Minerals Chapter 12. Water and the Body Fluids Water constitutes majority of body weight – Body composition Females Obese people Elderly."— Presentation transcript:

1 Water and the Major Minerals Chapter 12

2 Water and the Body Fluids Water constitutes majority of body weight – Body composition Females Obese people Elderly

3 Water and the Body Fluids Carries nutrients and waste products Maintains structure of large molecules Participates in metabolic reactions Serves as a solvent Acts as a lubricant and cushion Aids in regulation of body temperature Maintains blood volume

4 Water Balance and Recommended Intake Cellular fluids – Intracellular fluid – Extracellular fluid  Interstitial fluid  Intravascular fluid

5 Water Balance and Recommended Intake Water intake – Thirst and satiety Mouth, hypothalamus, and nerves – Thirst response lags behind the body’s need for water Dehydration symptoms – Water intoxication Symptoms

6 Signs of Dehydration

7 Water Balance and Recommended Intake Sources – Water – Beverages – Foods – Condensation reactions – Oxidation of energy-yielding nutrients

8 Water Balance and Recommended Intake Losses – Minimum excretion each day as urine – Vapor from lungs – Sweat from skin – Loss in feces Recommendations – Needs vary – AI for total water

9 Water Balance and Recommended Intake Health effects – Meet bodily needs – Protect against urinary stones & constipation – Concentration, alertness, and short-term memory – Type of water Hard water Soft water

10 Blood Volume and Blood Pressure Kidneys are central to blood volume and pressure maintenance Antidiuretic hormone (ADH) – Hypothalamus stimulates pituitary gland – Water-conserving hormone Stimulates kidneys to reabsorb water – Events trigger thirst

11 Nephron Function in the Kidney

12 Blood Volume and Blood Pressure Renin – Enzyme released by kidney cells when blood pressure is low – Kidneys reabsorb sodium Water retention Angiotensin – Renin hydrolyzes angiotensinogen to angiotensin I Convert to active form – angiotensin II

13 Blood Volume and Blood Pressure Aldosterone – Released from adrenal glands Release stimulated by angiotensin II – Signals kidneys Excrete potassium Retain sodium

14 Fluid and Electrolyte Balance Fluid balance – Two-thirds inside the cells – One-third outside the cells Dissociation of salt – Sodium – cation – Chloride – anion – Conduct electricity

15 Fluid and Electrolyte Balance Electrolytes attract water – Water molecules have net charge of zero Water follows electrolytes – Electrolytes predominantly outside of cell Sodium and chloride – Electrolytes predominantly inside of cell Potassium, magnesium, phosphate, sulfate – Selectively permeable membranes

16 Fluid and Electrolyte Balance Proteins regulate fluid movement – Attract water – Transport proteins Passage of ions across cell membranes Sodium-potassium pump Regulation of fluid and electrolyte balance – Two sites GI tract Kidneys

17 Fluid and Electrolyte Imbalance Causes of imbalance – Prolonged vomiting or diarrhea – Heavy sweating – Burns – Traumatic wounds – Some medications An imbalance can result in a medical emergency

18 Fluid and Electrolyte Imbalance Solutes lost depend on why fluid is lost – Vomiting or diarrhea – sodium – Tumor development – potassium Replacing lost fluids and electrolytes – Plain cool water and regular foods – Special replacement fluids

19 Acid-Base Balance Regulation of acidity – Narrow pH range to avoid life-threatening consequences Denaturation of proteins Concentration of hydrogen ions – High hydrogen concentration – acidic – Low hydrogen concentration – basic

20 The pH Scale

21 Acid-Base Balance Body defense against pH fluctuation – Buffers in blood Bicarbonate Carbonic acid – Respiration in lungs – Excretion in kidneys Bicarbonate

22 The Minerals – An Overview Major vs. trace minerals – Variation in amounts needed Inorganic elements – Always retain chemical identity – Cannot be destroyed by heat, air, acid, or mixing Body’s absorption and handling – Freely or with carriers

23 The Minerals – An Overview Bioavailability – Varies Food binders Nutrient interactions – Presence of other minerals Absorption, metabolism, and excretion Varied roles

24 Sodium Roles in body – Principal cation of extracellular fluid Primary regulator of volume – Acid-base balance – Nerve impulse transmission – Muscle contraction Sodium travels freely in the blood Kidneys: filter out and return what is needed

25 Sodium Recommendations – Diets rarely lack sodium – UL for adults Average intake in U.S. exceeds the UL Hypertension – Salt vs. sodium or chloride alone – Salt intake – DASH diet

26 Sodium Bone Loss (osteoporosis) – High salt intake is associated with increased calcium excretion Potassium as protective factor – DASH diet recommendation Food sources – Processed foods More sodium Less potassium

27 Sodium Deficiency – Conditions causing a deficiency Hyponatremia Toxicity – Acute Edema and high blood pressure – Chronic Hypertension

28 Chloride Essential nutrient Roles in the body – Major anion of extracellular fluids Moves passively across membranes Associates with sodium and potassium – Helps maintain fluid and electrolyte balance – Part of hydrochloric acid

29 Chloride Recommendations and intakes – Abundant in processed foods – Recommendations are slightly higher, but still equivalent to those of sodium Deficiency and toxicity – Diets rarely lack chloride – Conditions leading to deficiency – Toxicity – due to water deficiency

30 Potassium Principal intracellular cation Roles in the body – Helps maintain fluid and electrolyte balance – Helps maintain cell integrity – Aids in nerve impulse transmission and muscle contraction

31 Potassium Recommendations and intakes – Fresh foods are richest sources – AI for potassium Increase fruit and vegetable consumption Hypertension – Diets low in potassium – Diets high in potassium – Risk of stroke

32 Potassium Deficiency – Increase in blood pressure – Salt sensitivity – Kidney stones – Bone turnover – Irregular heartbeats – Muscle weakness – Glucose intolerance Toxicity – No UL – Overconsumption of potassium salts or supplements – Certain diseases or treatments – Kidneys accelerate excretion

33 Calcium Most abundant mineral in the body Adequate intake – Grows a healthy skeleton in early life – Helps minimize bone loss in later life Majority of body’s calcium is in bones and teeth – Part of bone structure – Calcium bank

34 Calcium In bones – Calcium salts form crystals Hydroxyapatite – Strength and rigidity to maturing bones – Bone remodeling In teeth – Fluoride stabilizes calcium crystals in teeth

35 Calcium In body fluids – Helps to maintain normal blood pressure – Extracellular calcium Participates in blood clotting – Intracellular calcium Regulation of muscle contraction Transmission of nerve impulses Secretion of hormones Activation of some enzyme reactions

36 Calcium Disease prevention – Hypertension – Blood cholesterol – Diabetes – Colon cancer Obesity – May help maintain healthy body weight Inverse relationship with food sources

37 Calcium Calcium balance – Involves system of hormones and vitamin D Parathyroid hormone & calcitonin – Organ system response Intestines Bones Kidneys – Calcium rigor – Calcium tetany

38 Calcium Absorption – Adults absorb about 30% of the calcium ingested Stomach’s acidity – calcium soluble Vitamin D – calcium-binding protein – Efficiency and inadequate intakes – Factors that enhance calcium absorption – Factors that inhibit calcium absorption

39 Calcium Recommendations – Based on amount needed to retain calcium in bones Peak bone mass – Set high enough to accommodate 30% absorption rate – UL has been established – Adverse effects from supplements

40 Calcium Milk products – Calcium is most abundant in milk products – Conceal milk products in foods – Consequences of drinking too little milk Other foods – Bioavailability – Fortified juices and foods Calcium and iron

41 Bioavailability of Calcium from Selected Foods

42 Calcium Deficiency – Peak bone mass by late 20s – All adults lose bone with age Begins between 30 and 40 years of age – Osteopenia – Osteoporosis Silent disease Blood samples offer no clues

43 Phases of Bone Development Throughout Life

44 Phosphorus Second most abundant mineral in body – Hydroxyapatite crystals of bone and teeth Roles in body – Part of major buffer system – Part of DNA and RNA – Assists in energy metabolism – Helps transport lipids in the blood – Structural component of cell membranes

45 Phosphorus Recommendations and intakes – Deficiencies are unlikely – Best sources Foods rich in proteins – Phosphoric acid intake and bone density – UL has been established

46 Magnesium Body locations – More than half is found in the bones Reservoir – Muscles and soft tissues – Extracellular fluid

47 Magnesium Roles in body – Maintains bone health – Part of protein making machinery – Necessary for energy metabolism – Participates in enzyme systems – Catalyst in ATP production – Muscle contraction and blood clotting – Supports normal function of immune system

48 Magnesium Intakes – Average dietary intake for U.S. adults is below recommendations – Hard water contributions Sources – Legumes, seeds, and nuts – Leafy green vegetables

49 Magnesium Deficiency – Rarely occurs Occurs with diseases – Causes tetany and impair central nervous system activity Hypertension – Protective factor Toxicity

50 Sulfate Sources of sulfate – Food and beverages – Amino acids Methionine Cysteine No recommended intake – Normal protein intake


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