Presentation on theme: "Water & The Major Minerals Chapter 12. Water & the Body Fluids Water – Makes up 60% (3/5) of adults body weight. Higher for children – Makes up 75% (3/4)"— Presentation transcript:
Water & The Major Minerals Chapter 12
Water & the Body Fluids Water – Makes up 60% (3/5) of adults body weight. Higher for children – Makes up 75% (3/4) of lean muscle. 25% (1/4) of fat – Males have more water (more lean muscle) Females, the elderly, obese have less
Water & the Body Fluids Water in body fluids: – Carries nutrients & waste products through the body. – Maintains structure of large molecules. – Participates in metabolic reactions. – Serves as a solvent so substances can participate in metabolic reactions. – Acts as a lubricant & cushion around joints, inside eyes, in the spinal cord, & as amniotic sac during pregnancy. – Aids in regulation of body temperature. – Maintains blood volume.
Water Balance & Recommended Intakes Fluid inside cell – Intracellular fluid Fluid outside cell – Extracellular fluid Interstitial fluid – Fluid surrounding cells Composition between the two differs. Composition in each remains constant under normal conditions.
Water Balance & Recommended Intakes Water intake – Influenced by thirst & satiety Sensed by hypothalamus & nerves.
Water Balance – Dehydration : loss of water & loss not replaced. Symptoms: – Water intoxication (rare) : excessive water consumption, may result due to a kidney disorder which reduces the amount of urine produced. Symptoms Hyponatremia
Water Sources – Nearly all foods contain water – Water is produced during cellular respiration & during condensation reactions.
Water Balances Water losses – Body must excrete a minimum of 500 mL (~ 2 cups) of urine a day. Reason – Water is also lost As sweat From lungs as vapor In feces – Average daily losses
Water Balance Water Recommendations – Water needs vary depending on diet, environmental conditions, activity, & humidity. – Sometimes expressed in proportion to amount of energy expended under average environmental conditions. For a person that expends 2000 kcal a day, the amount is 2 – 3 L (8 – 12 cups). – Agrees with AI for total amount set by DRI. If physically active or a hot day, a person will probably need more.
Water Balance Water Recommendations (continued) – Any beverage can meet fluid needs. Caffeinated beverages – Caffeine acts as a diuretic. » Causes more water to be lost. – People can consume it to meet daily fluid needs, however. Alcohol – Acts as a diuretic. – Should not be used to meet daily fluid needs.
Water Balance Health Effects of Water – Protection against – Hard or Soft Water makes a difference
Water Balance Bottled water – people may think its better & safer. – Not necessarily true in US. Distilled water – Has all minerals removed. Natural water – Comes from spring or well – Mineral content may not be changed. Mineral water – Comes from spring or well – Contains more minerals. Minerals give it unique taste. – Usually has higher sodium content.
Blood Volume & Blood Pressure Kidneys are major control for homeostasis of body fluids. – Kidneys regulate blood volume which influences blood pressure. – Kidneys reabsorb needed substances. – Kidneys excrete metabolic wastes with some water.
Fluid & Electrolyte Balance Dissociation of Salt in Water – Mineral salts dissociates (separates) into ions when dissolved in water. Ions - – Positive ions called cations. – Negative ions called anions. Electrolytes – salts that dissolve in water & dissociate into ions. conduct electrical currents.
Fluid & Electrolyte Balance Dissociation of Salt in Water (continued) – Electrolyte Balance Major extracellular ions Major intracellular ions
Fluid & Electrolyte Balance Electrolytes attract water – Water has net charge of zero. – Water is polar molecule Hydrogen Oxygen
Fluid & Electrolyte Balance Water Follows Electrolytes – Water moves across cell membranes when electrolytes move across. – Osmosis – Osmotic pressure
Osmosis (p. 391)
Fluid & Electrolyte Balance Proteins Regulate Flow of Fluids & Ions – Sodium –Potassium Pump (protein) Regulates Regulation of Fluid & Electrolyte Balance – GI tract & Kidneys regulate GI tract Kidneys
Fluid & Electrolyte Imbalances Different Solutes Lost by Different Routes – Solutes lost due to vomiting, sweating, bleeding or diarrhea Sodium and chloride – Adrenal gland tumor Oversecretion of aldosterone Kidneys may excrete too much potassim. – Uncontrolled diabetes Excretion of glucose
Fluid & Electrolyte Imbalances Replacing Lost Fluids & Electrolytes – Normal replacement of lost fluids Drink water – Severe cases ORT (oral rehydration therapy)
Acid – Base Balance Ions also regulate acidity of fluids. pH of body (7.35- 7.45) must be maintained otherwise life threatening situations result. – Examples Acidity is determine by H + 3 system defend against pH fluctuations
Acid-Base Balance Systems to prevent pH fluctuations – 1. Regulations by Buffers – 2. Regulation in the Lungs Raising & slowing respiration rate – 3.Regulation in Kidneys Reabsorb or excreting bicarbonate.
The Minerals - Overview Inorganic – Retain chemical identity – Remain in body until excreted – Cant be changed into anything else – Cant be destroyed by heat, air, acid, or mixing. Bodys Handling of Minerals
The Minerals - Overview Variable Bioavailability – Binders Found in some foods. – Prevent mineral absorption » Phytates » Oxalates
Sodium Sodium Roles in body – Maintains normal fluid electrolyte balance – Assists in nerve impulse conduction – Assists in muscle contraction Sodium & Hypertension
Sodium Sodium & Bone Loss – Calcium excretion increased with high salt intake. – See in summary: p. 397
Chloride Chloride Roles in Body – Maintains normal fluid & electrolyte balance. – Part of HCL – Necessary for proper digestion
Potassium Potassium Roles in Body – Maintains normal fluid & electrolyte balance. – Assists in may reactions. – Supports cell integrity – Assists in nerve impulse conduction. – Aids in muscle contraction. Potassium & Hypertension
Calcium Calcium Roles in Body – Mineralization of bones & teeth. – Involved in muscle contraction & relaxation. – Important in nerve functions, blood clotting, blood pressure.
Calcium Calcium in bones – As bones form, calcium forms hydroxyapatite on matrix of collagen. As mineralization continues, bones become denser & stronger. – Bones constantly remodeled. Bones gain & lose minerals Children gain more than they lose. – Teeth Formed in similar pattern, but they are not bone. Fluoride hardens & stabilizes the crystals of teeth
Calcium Calcium in body fluids – Extracellular fluids Helps maintain blood pressure – Reason Also participates in blood clotting. – Intracellular fluids Binds to proteins and activates them – Proteins participate in
Calcium Calcium & Disease Prevention – May protect against hypertension. Calcium & Obesity – May help maintain a healthy body weight.
Calcium Calcium absorption – Factors to enhance absorption Acidity of stomach keeps Ca soluble. Vitamin D helps to make the calcium binding protein needed for absorption. – Factors that inhibit absorption (many that enhance also inhibit) Lack of stomach acid Vitamin D deficiency High phosphorus intake Phytates Oxalates
Calcium Calcium in Milk – Calcium most abundant in milk – Consequences of drinking too little milk. Calcium in other foods – Tofu – Almonds – Broccoli
Calcium Calcium Deficiency – Stunted growth in children – Osteoporosis in adults Toxicity Symptoms – Constipation – Risk of kidney stones – Interference with absorption of other minerals.
Phosphorus Phosphorus Roles in Body – Mineralization of bones & teeth – Part of every cell – Important in genetic material – Part of phospholipids – Used in energy transfer & in buffer systems Phosphorus Deficiency – Muscular weaaakness – Bone pain
Magnesium Roles in Body – Bone mineralizaiton – Building of proteins – Enyme action – Muscular contraction – Nerve impulse conduction Deficiency – Weakness – confusion
Sulfate Part of proteins Stabilizes protein shape – Disulfide bridges