Chapter 7: fluid & electrolyte balance Flashcards
what should you do preserve vitamins inside food?
minimize contact with water, reduce heat, limit light, avoid air, ban basics
do younger people or older people have more body fluid?
younger people (more lean tissue)
do males or females have more body fluid?`
males
what is the function of fluids?
protect & lubricate our tissues: brain, spinal column, joints, fetus, GI tract, lungs
what is body fluid made up of?
water & electrolytes (charged ion)
what is the role of water in transporting substances?
water is an excellent solvent, so it can transport ions, carbohydrates, amino acids, vitamins, and minerals to cells
high blood volumes causes what?
hypertension (high blood pressure)
low blood volume causes what?
hypotension (low blood pressure)
fluid accounts for what component of blood?
blood volume
how does water maintain body temperature?
1) water has a high heat capacity, meaning it takes a lot of energy to raise water temperature so the temp of our body fluids remains stable
2) evaporative cooling: sweating (heat is transported from the body core through the bloodstream to skin’s surface)
what are the functions of electrolytes?
enable our nerves to respond to stimuli and signal our muscles to contract (movement of Ca2+ into a muscle cell stimulates contraction)
what does normal cell function depend on?
proper fluid and electrolyte balance
how does water move in the body?
it follows solutes and it moves freely across membranes
what are the stimuli for the thirst mechanism?
increased [salt] or [solutes] in blood, decreased BV and BP, dry mouth or throat
what brain region initiates the thirst mechanism?
hypothalamus
what are the pitfalls of the thirst mechanism?
it may not be sufficient; it turns on a bit late and off a bit early
what are the ways in which water is lost from the body?
urine, feces, sweat, evaporation, exhalation
what are the ways in which water enters the body?
beverages, food, metabolic reactions
what is the recommended intake of water for males?
3.7 L (3.0 L as beverages)
what is the recommended intake of water for females?
2.7 L (2.2 L as beverages)
what does the recommended intake of water vary with?
age, size, health status, environment, activity level
what happens if you drink too much water?
hyponatremia, water intoxication
what happens if you don’t drink enough water?
dehydration, infants and elderly are especially vulnerable
what are the functions of sodium?
fluid & electrolyte balance, associated with blood pressure and pH balance in the body, required for nerve impulse transmission, assists in the transport of certain nutrients (e.g. glucose) into body cells
what is the AI for sodium?
1500 mg/day
what is the RDI of sodium?
less than 2300 mg/day is recommended
how much sodium does the average American consume?
more than the RDI, 3400 mg/day
what populations must pay special attention to sodium intake?
hypertension, chronic heart failure, kidney disease, osteoporosis