What happens to the percentage of body water through the lifespan? - correct answer
Newborns; 75-90%
Childhood; 60-65%
Adults; 60%
Older adults; declines with age
Why do older adults experience a decrease in body percentage of water? - correct answer -
increased adipose tissue
- decreased muscle mass
- renal decline
- diminished thirst
What is the definition of osmotic force? - correct answer Amt. of hydrostatic pressure required
to oppose the osmotic movement of water.
What is filtration? - correct answer movement of fluid from the capillary into the interstitial
space
What is reabsorption? - correct answer movement of fluid from interstitial space into the
capillary
What is capillary hydrostatic pressure? - correct answer (blood pressure) facilitates the outward
movement of water from the capillary to the interstitial space
What is capillary oncotic pressure? - correct answer Water pulling
attracts water from the interstitial space back into the capillary osmotically
What is interstitial hydrostatic pressure? - correct answer Water pushing.
facilitates the inward movement of water from the interstitial space into the capillary
What is interstitial oncotic pressure? - correct answer water pulling
attracts water from the capillary into the interstitial space osmotically.
,What is Starlings hypothesis? - correct answer Net filtration = forces favoring filtration - forces
opposing filtration
What forces favor filtration? - correct answer 1. Capillary hydrostatic pressure (blood pressure)
2. interstitial oncotic pressure (water pulling)
What forces oppose filtration? - correct answer 1. Plasma (capillary) oncotic pressure (water
pulling)
2. Interstitial hydrostatic pressure
What is the major force of filtration and reabosoprtion? - correct answer capillary pressures
What happens at the arteriole end of the capillary in terms of fluid forces? - correct answer
hydrostatic pressure > interstitial oncotic pressure = water into the insterstitial space
FILTRATION
What happens at the venous end of a capillary in terms of fluid forces? - correct answer
capillary oncotic pressure > interstitial hydrostatic pressure = fluid back into ciruclation
REABSORPTION
What is the pathophysiology of edema? - correct answer increased in forces favoring fluid
filtration from the capillaries or lymphatic channels into the tissues
What is the primary ECF cation? - correct answer Sodium
What is the primary ECF anion? - correct answer Chloride
Describe the relationship btw. Chloride and sodium and bicarbonate - correct answer Cl follow
sodium and varies inversely with bicarb.
What hormone regulates sodium? where is it synthesized? - correct answer Aldosterone.
Synthesized in the adrenal cortex.
When is aldosterone secreted? - correct answer Decreased renal perfusion, low NA levels, high
K levels.
What are the effects of aldosterone secretion? - correct answer Acts on the distule tubule of
the kidney to reabsorb sodium and water and excrete K and H+ into urine.
Describe the renin-angiotensin-aldosterone system - correct answer decreased blood pressure
causes the juxtaglomerular cells of kidney to secrete renin
, renin stimulates angiotensin I
angiotensin I converted to angiotensin II by ACE in pulmonary vessels
angiotensin II:
- stimulates aldosterone secretion
- causes vasoconstriction
leads to reabsorption of Na/H20, rise of systemic BP restoring renal perfusion... all negative
feedback that inhibits further release of renin
What produces ANP? Urodilantin? - correct answer myocardial atria
urodilantin is similar to ANP and is secreted by kidney cells in response to increased renal blood
flow.
Where is BNP produced? - correct answer ventricles
ANP and BNP are antagonist to what - correct answer RASS and stop secretion of aldosterone,
renin, and AD and the action of angiotensin II
Thirst perception is regulated by; - correct answer 1. Osmolality receptors (cause thirst ex: dry
mouth, plasma volume depletion)
2. Baroreceptors (stimulated by depleted plasma volume to cause release of ADH)
What does ADH (arginine vasopressin) do? When is is released? - correct answer - increases
H20 absorption by increasing permeability of renal tubules in collecting ducts of kidneys
- released with increased plasma osmolality, decreased circulating blood vol., decreased BP
What is osmolality? normal value? - correct answer Number of particles per kg of H20. Doesn't
depend on particle size, just number of particles.
normal = 295
What does high/low osmolality indicate - correct answer low (less 295) = fluid overload