Chapter 11: Water and Electrolytes Flashcards
water accounts for _____ of the total body weight of an adult, making it the most abundant constituent of the body
60%
sodium, calcium, potassium, chlorine, phosphate, and magnesium are all
electrolytes
water distribution
body water is found in 2 major compartments
intracellular and extracellular
water distribution
compartment with its intracellular fluid (ICF)
intracellular
water distribution
compartment with its extracellular fluid (ECF)
extracellular
water distribution
intracellular - approximately _____ L
30 L
major cation - intracellular
potassium
major anion - intracellular
phosphate
water distribution
extracellular - approximately _____ L
15-17 L
major anion - extracellular
chloride
major cation - extracellular
sodium
extracellular (3)
all fluids within the blood vessel (around 3 L)
intravascular fluid compartment
extracellular (3)
fluids around and between the cells
intercellular, interstitial, or extravascular fluid
extracellular (3)
fluids in the eyeball (vitreous humor), around the joints (synovial fluid), and within digestive secretions
transcellular fluid compartment
is the maintenance of normal ECF or the external environment of the cells
homeostasis
water balance - maintenance
the body regulates both water _____ and _____
intake and excretion
water balance - maintenance
thirst and satiety govern our water intake, sensed by the _____ (3)
mouth, hypothalamus, and stomach
water balance - maintenance
the excretion of water, involves the brain cells (2) and _____
cells of hypothalamus and pituitary gland
kidney
water balance of fluid balance is achieved through the (2)
-control of fluid intake;
-control of rate of fluid lost through kidneys
water balance - maintenance
maintain through the actions of hormones (2)
anti-diuretic hormone and aldosterone
water balance is disturbed in
refers to a condition resulting from excessive water loss, accompanied by losses of electrolytes
dehydration
water balance is disturbed in
a condition that results from excessive intake of fluids without an equivalent amount of salt
overhydration or water intoxication
regulators of water balance
hormonal control
renin-angiotensin-aldosterone (RAA) mechanism
regulators of water balance
an enzyme from the kidneys tat is secreted in response to low renal blood flow
converts the plasma proteins angiotensin I to angiotensin II
renin
regulators of water balance
hormone from the adrenal cortex that stimulates sodium retention
aldosterone
regulators of water balance
secreted by the pituitary gland
retains water
vasopressin or ADH
water requirements
to compensate for water losses, the body must take in daily at least _____ of water based on a recommended intake of 1mL per kcal of energy expenditure
2.5 L
products of ionization of salt, acid, or base dissolved in water, are electrically charged particles;
exists as anions and cations distributed throughout the fluid compartments of the body
electrolytes
electrolytes
negatively-charged particles
ex: chloride, bicarbonates phosphatase, and sulfates
anions
electrolytes
positively-charged particles
ex: sodium, potassium, calcium, and magnesium
cations
daily requirements for water
infants (birth to <6 months)
800 mL
daily requirements for water
infants (6 months to <12 months)
1000 mL
daily requirements for water
children (1-18 y/o) acc to weight
10-20 kg
1000 ml + 50 ml/kg for each kg in excess of 10
daily requirements for water
children (1-18 y/o) acc to weight
>20 kg
1000 ml + 20 ml/kg for each kg in excess of 20
daily requirements for water
adults older than 18 y/o
2500 ml
daily requirements for water
older persons than 65 y/o
1500 ml
daily requirements for water
pregnant women (2500 ml)
+ 300 ml
daily requirements for water
lactating women (first 6 months) (2500 ml)
+750 - 1000 ml
electrolyte balance
used by the body to help regulate the distribution, composition, and acidity of fluids
without these, water molecules in the body move freely across cell membranes
cells have no way to hold onto water molecules directly, with the help of electrolytes, cells move water by indirect means as water follows salt or electrolytes
electrolytes
electrolyte balance - mechanism
_____ (both ecf electrolytes) and _____ (both icf electrolytes) are the major electrolytes regulating the water movement
sodium and chloride;
potassium and phosphatase
electrolyte balance - mechanism
when water loss exceeds electrolytes loss, the ECF becomes _____ in relation to the ICF
water moves from the cells to the ECF to restore equilibrium
hypertonic
electrolyte balance - mechanism
when water enters the ECF with insufficient electrolytes to maintain the density of the solution, the EC becomes _____ and moves into the cell
hypotonic
electrolyte balance - mechanism
other mechanisms involve a balance between _____ (exerted by the proteins in plasma, keeps the fluids inside the blood) and _____ (exerted by the pumping action of the heart on the fluids outside the blood vessels)
oncotic pressure; hydrostatic pressure
acid-base balance
body has certain buffer systems and uses _____ to help maintain water balance and regulate the acidity (pH) of fluids
ions
acid-base balance
the most important electrolyte buffering system is the _____ system in the blood
bicarbonate buffer
maintenance of acid-base
acid-balance or _____ concentration must be controlled
hydrogen ion
maintenance of acid-base
plasma pH is
pH 7.4
maintenance of acid-base
optimal pH at which the body can operate ranges from
pH 7.35 to pH 7.45
