Chapter 24: Water & Electrolyte Flashcards
Newborn baby’s body weight is about
75% water
Total body water (TBW)
content of average young adults is 60% in men and 50% in women
obese and elderly people body water %
as little as 45% by weight
why is women’s totals body water average slightly less?
they have more adipose tissue, which displaces water
Fluid compartments
areas separated by selectively permeable membranes and differing in chemical composition
ECF is divided into
- 25% tissue (interstitial) fluid
- 8% blood plasma and lymph
- 2% transcellular fluid
intracellular fluid (ICF) %
65%
extracellular fluid (ECF)
35%
Fluid balance
when daily water gains and losses are equal (about 2,500 mL/day)
gains come from which two sources?
metabolic water and performed water
Metabolic water
formed by aerobic metabolism and dehydration synthesis
Preformed water
ingested in food and drink
cutaneous transpiration
water that diffuses through epidermis and evaporates
Insensible water loss
not usually aware of it; breath and cutaneous transpiration
Sensible water loss
noticeable output; urine and moderate sweating
Fluid deficiency
fluid imbalance that arises when fluid output exceeds intake over long period of time