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20 Cards in this Set
- Front
- Back
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Water - Basics |
Makes up 45-75% of body weight Muscle tissue = nearly 75% water by wt Adipose tissue = 10% of water by wt Water's chemical for H20 Hydrogen bonds between hydrogen, oxygen creates water's strong surface tension, high heat capcity, dissolving capabilities Electrolyte/water balance Proportions of each must stay within a narrow range Maintained through intake, excretion of h2o Movement of ions |
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Water - Functions |
Carries waste out of body in urine Resistance temp changes (heat capacity) Cooling aka sweating Chemical reactions pH balance Body fluids |
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Water and Electrolytes |
A delicate equilibrium Electrolyte solutions, pos charges is equal to neg ions. |
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Cations |
Positively charged ions Ex: sodium potassium |
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Anions |
Negatively charged ions Ex: Chloride, Phosphate |
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Water in the Body |
2/3 of body is in intracellular fluid Main cation in intracellular: Potassium 1/3 of body is in extracellular fluid Main cation in extracellular fluid: Sodium Interstitial Fluid Plasma |
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Water - Adequate intake |
Water, beverages, food Men = 3.7 L Women = 2.7 L Pregnant = 3 L Lactating = 3.8 L 81% come from beverages 19% comes from food 250-300 ml of water produced by body |
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Water - Excretion |
Lungs - water evaporates via exhale Skin - perspiration, evaporation GI tract - feces Kidneys - urine |
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Insensible water loss |
Continuous evaporation of water from lungs and skin 1/4 to 1/2 of daily fluid loss High altitude, low humid, high temp incr losses During flight: Low cabin humidity = insensible fluid losses of 32-48 oz of water |
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Water Excretion |
Insensible water losses Rise during sickness Increase fluid intake when sick Elimination of wastes Urea Breakdown product of protein metab Major component of urine Overconsumption of protein, salt causes kidneys to work harder More protein, salt = more fluids you need to consume. |
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Water Balance |
Maintained through thirst, water excretion Fluid balanced between compartments Total body water regulated -Fluid excretion -Blood volume and pressure -Thirst -Water reabsorption in the GI tract |
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Osmoreceptors |
Neurons in the hypothalamus that detect changes in the fluid concentration in blood and regulate the release of antidiuretic hormone Causes water reabsorption in kidneys |
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Antidiuretic Hormone ADH |
Peptide hormone secreted by pituitary gland. It increases blood pressure and prevents fluid excretion by the kidneys aka vasopressin |
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Renin-Angiotensin System |
Response to dietary sodium Balances extracellular fluid volume, blood pressure Water follows sodium Increase in sodium intake increases extracellular fluid volume, BP Decreased retention of sodium, water Resulting excretion returns levels to normal Decrease in sodium intake triggers opposite effect. |
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Thirst |
Increase in osmolarity Reduction in blood volume and pressure Increase in angiotensin 2 Dry mouth and esophagus |
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GI Tract |
Requires many liters of fluid each day Rapid dehydration if water from all bodily secretions exited through feces Diuretics (increase fluid loss) |
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Alcohol |
Suppresses ADH production Excess consumption can cause dehydration= hangover |
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Caffeine |
Effects of caffeine on hydration are inconsistent Some say it causes chronic mild dehydration. Others say it helps contribute to total water intke. |
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Dehydration |
Major worldwide killer Infants & older adults vulnerable GI infections are responsible Diarrhea, vomiting leads to water loss Water losses can equal 20% of body weight Leads to coma, death Burns can cause deadly dehydration Diminished physical, mental performance: Fluid deficit of 1-2% of body wt can cause: -Decline in alertness -Decline in concentration capability -Increases feeling tired -Headaches Impaired decision-making, reaction times |
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Overhydration |
Acute water toxicity Caused by rapid consumption of large amounts of h2o Can exceed kidney max excretion rate (0.7-1L per hour) Untreated glandular disorders Causes excessive water retention Symptoms: headaches, then seizures, and then possibly death |
