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26 Cards in this Set
- Front
- Back
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Factors Influencing % Body Water
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-age (water content decreases with age)
-gender (muscle is more water than fat) -muscle mass and fat composition (men tend to be more muscle than women) |
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Functions of Water in the Body
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-universal solvent (polar molecule, neutral charge overall)
-transport of solutes -temperature regulation -lubrication for joints -protective cushion and bathes organs -structural component to the cells -essential for acid-base maintenance -Chemical Reactions (condensation and dehyration) |
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Water Balance
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-Water intake equals water excretion
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Water Intake
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-from fluids, foods, and metabolism
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Water Excretion
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-urine, feces, sweat and breathing (insensible water loss)
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Water Lost Through Sweat
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Varies based on:
1. environmental factors (temp, humidity, wind, sun's intensity, and clothing) 2. Amount of Physical activity 3. Training Status |
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Location of fluid in the body
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1. Intracellular (60%)
2. Extracellular (40%)--80% is interstitial fluid, 20% is plasma--driven by osmolarity |
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Electrolytes
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-minerals with electrically charged ions
-Cations and anions -only a small percentage of molecules in fluids are non-electrolytes (glucose, urea, and creatine) |
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Osmosis
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movement of water from high to low concentration
-passive process, no NRG is required -water moves to the area with higher concentration of solutes |
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Osmolarity
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-the total concentration of dissolved particles
-glucose=1 particle -NaCl=two particles -strongest factor that influences water balance in between compartments |
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Osmotic Pressure
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-amount needed to exert to stop water from moving
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Na-K Pump
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-transports 3 Na out of the cell and 2 K into the cell
-Na and K play a key role in water concentration inside and out of the cells -intracellular/extracellular ion concentrations -Osmotic gradient is established -driving force for fluid and Na+ coupled transport |
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How Water and Sodium affect Blood Pressure
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-direct relationship between blood volume and pressure
-kidneys help regulate blood volume and electrolyte balance through tightly controlled hormone signals (ADH--vasopresin, Aldosterone, and Angiotensin) |
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ADH aka Vasopresin
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-produced by the posterior pituitary
-acts on kidneys to increase water retention -regulated by baroreceptors (sense the decreased plasma volume) and osmoreceptors (senses the osmolarity in the blood) - |
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Disorders associated with ADH
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-diabetes insipidus
symptoms: polyurea and polydypsia -two types: nephrogenic and hypothalamic |
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Renin Angiotensin System
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Renin is secreted by the kidneys
-renin secretion is controlled by 1. decrease in arterial pressure 2. decrease in NaCl in filtrate 3. Decrease plasma concentration of Na -increases Na reabsorption--opposite effect of aldosterone |
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Water Intake on a Daily Basis
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-80% from fluids
-20% from food -Women: about 9 cups/day -Men: about 13 cups/day |
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Caffeine
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-mild diruetic
-doesn't cause a loss of body water |
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Alcohol
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-inhibits ADH
-induces urination--can be dehydrating -effects potassium concentration in the blood |
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Hypertension
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-high blood pressure--can be reduced by diuretics
-promotion of diuresis by inhibiting the reabsorption of sodium -increased sodium excretion increasing fluid excretion -reduces blood volume and lowers blood pressure |
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Water Imbalances
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1. overhydration
2. dehydration |
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Dehydration
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caused by:
1. prolonged diarrhea or vomiting 2. excessive sweating -water is depleated from ECF and ICF--changes in cell function |
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Effects of Dehydration
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-loss of short term and long term memory
-lower attention span and cognition -reduced ability to maintain core temperature -increased risk of urinary tract infections and fatigue -elderly, athletes and children are especially at risk |
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Thirst Mechanism
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-sign of dehydration
-urge to drink is important in preventing dehydration and restoring water balance -less circulation of blood can lead to reduced blood pressure, and hypotension if it is severe enough |
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Hyponatremia
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-water intoxication
-rapid consumption of water--decreasing the plasma sodium concentration -water is drawn into the cells -increasing ISF tonicity and water is drawn from the blood -cause swelling in cells--coma and death are possible |
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Ways to Monitor Hydration
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1. weigh oneself before and after a workout
2. monitor the color of urine excreted (really yellow? dehydrated) |
