Ch 14; water & major minerals Flashcards
water
-no energy, 2nd most important thing in life (oxygen), no digestion, absorption, metabolism
% of human body water
50-75%
brain 70%, lungs 90%, lean muscle 75%, blood 83%,
bodily water % vary by
gender, age, body fat content, and body structure
-infants children the most, seniors the least %
2 body compartments (water)
1) intracellular fluid
- 2/3 of bodes water
2) extracellular fluid
- interstitial (fluid b/w cells)
- intravascular (fluid in blood & lymph)
water myths (3)
- caffeine is dehydrating: only a mild diuretic (only feel dehydrated)
2) alcohol provides water: increases dehydration risk by ADH on kidneys
3) bottled water is healthier - 40% comes from tap, missing minerals
water needs vary on what
body size, physical activity, environmental conditions & dietary intake
AL for total water male & female
men: 25 cups
women: 11 cups
water organ regulators
kidneys, brain, lungs, liver
body’s response to loss of water
- water shifts freely in and out of cell
- controlled by electrolytes (water follows electrolytes)
- blood volume decreases, decreasing blood pressure
water regulated by what hormones & enzymes
- anti-diuretic hormone (ADH)
- renin-angiotensin system (causes vasoconstriction)
- aldosterone
causes of dehydration
low intake, diarrhea, intense exercise, vomiting, hot weather, high altitudes
-thirst not good in children, elderly, ill, w/ exercise
dehydration signs
dry mouth & skin, fatigue, muscle weakness, decreased urine output, dark yellow urine, headache, dizziness, hallucinations
water toxicity
hyponatremia (drink less water, increase sodium)
mineral?
essential inorganic elements needed in small amounts in the diet for normal function, growth & maintenance of body tissues
minerals ____ be synthesized in body
can’t
minerals divided into 2 categories
1) macrominerals
- greater than 100mg/day
2) microminerals (trace elements)
- less than 100 mg/day
mineral food source
from both plants & animals
-quantity influenced by agricultural factors
transportation & excretion of minerals
- once absorbed, travel in blood in free form or bound to protein
- excretion: primarily through urine
- w/ kidney damage, mineral intake must be controlled to avoid toxicity
functions of minerals
- cellular, tissue, organ, systemic = minerals are critical
- metabolism
- water balance
- nerve impulse transmission
- body components
common mineral deficiencies (major & minor)
major: Ca, Potassium, magnesium
minor (trace): iron, zinc, iodine
toxicity in minerals
seen in trace minerals w/ supplementation (iron, zinc)
sodium in foods
NaCl: 40% sodium, 60% chloride
-1 tsp = 2300 mg
excretion of sodium
mainly urine, feces, perspiration
sodium functions (3)
1) absorption of glucose & some AA in SI
2) required for normal muscle & nerve function
- muscle contraction
- conduction of nerve impulses
3) water balance