-
The average adult contains _________ liters of fluid
40
-
Healthy males are ______% water
60
-
Healthy females are ______% water
- 50
- because females have higher body fat % and smaller amount of skeletal muscle
-
Old age _______% of body water weight
45
-
Water is a ___________ solvent
universal
-
Solutes are classified into
Electrolytes and Non electrolytes
-
Electrolytes
- inorganic salts, all acids, bases and some proteins
- Have greater osmotic power than non electrolytes
-
Non electrolytes
glucose, lipids, creatine & urea
-
Expressed in miliequivalents per liter mEq/L or a measure of the number of electrical charges in 1L of solution
Electrolyte Concentration
-
single charged ions
1mEq= 1mOm
-
bivalent ions
1mEq= 1/2 mOm
-
Water occupies 2 main fluid compartments
- Intracellular fluid ICF- contained in cells 2/3 by volume
- Extracellular fluid ECF - plasma fluid portion of blood & interstitial fluid in spaces between cells & ECF
-
ECF
- lymph
- cerebral spinal fluid
- eye humors
- synovial fluid
- serous fluid
- gastrointestinal secretions
-
ICF= _____% of total body fluids
63
-
ECF= _____% of total body fluids
37%
-
mEq/L =
- concentration of ion mq/L
- _______________________
- atomic weight of ion
-
______% of the mass of solutes in plasma
90%
-
______% of the mass of solutes in interstitial fluid
60%
-
______% of the mass of solutes in intracellular compartment
97%
-
Potasium and protein found in high concentrations in ?
Cells
-
Sodium found in _______ concentrations in cells
low
-
compartmental exchange is regulated by
osmotic and hydrostatic pressure
-
net leakage of fluid from blood is picked up by
lymphatic vessels and returned to blood stream
-
ion fluxes are restricted by
more selectively by active transport
-
Nutrients, respiratory gases and wastes
more unidirectionally
-
Plasma is the only fluid that
circulates throughout the body links external and internal environments
-
Osmolalities of the body fluid are
-
to remain properly hydrated water intake must =
water output
-
Water intake sources
- Ingested fluid 60%
- solid food 30%
- Metabolic water or water oxidation 10%
-
water output
- urine 60%
- feces 4-6%
- Insensible losses 28%
- sweat 6-8%
-
increases in plasma osmolality trigger thirst and release of
antidiuretic hormone (ADH)
-
should take in _______ and release ______of fluids
2.5L or 2500ml
-
hypothalamic thirst center stimulated by
- decline in plasma volume 10-15%
- increase in plasma osmolality 1-2% - increase solute load
- total body water just needs to decrease by 1%
-
hypothalamic thirst center
sensed by baroreceptor input, angiotensin II, or other stimuli
-
Thirst quenched
as soon as we begin to drink water
-
Feedback signals that inhibit the thirst centers
- Moistening the mucosa of the mouth and throat
- activation of stomach & intestinal stretch receptors
-
Obligatory water losses
- insensitive losses from lungs & skin
- water accomplishes undigested food residues in feces
-
Obligatory water loss reflects that
kidneys excrete 900-1200 mOm of solutes to maintain blood homeostasis
-
Urine solutes must be
flushed out of the body in water
-
water reabsorbtion in collecting ducts is proportional to release of
ADH
-
Low ADH levels =
- produce dilute urine
- reduces volume of body fluids
-
High ADH levels =
produce concentrated urine
-
Hypothalamic osmoreceptors
trigger or inhibit ADH release
-
Factors that trigger or inhibit ADH release
- prolonged fever
- excessive sweating
- vomiting
- diarrhea
- severe blood loss
- traumatic burns
-
dehydration
- body in negative fluid balance
- hemorrhage, severe burns, prolonged vomiting, diarrhea water deprivation & diuretic abuse
-
dehydration leads to
- weight loss, fever, mental confusion
- hypovolemic shock loss of electrolytes
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