Intro to Renal Physiology Flashcards
what are the five regulatory functions of the kidney?
managing extracellular fluid volume, osmolarity and ion composition, clearing metabolic end products, toxins and drugs and endocrine functions
describe the kidney’s support of cardiovascular function?
it maintains adequate blood pressure and blood flow y regulating volume
what percentages of body weight are total body water, intracellular fluid and extracellular fluid?
TBW is 60%, ICF is 40% and ECF is 20%
how many L is in 1 kg?
one
what percentage of ECF is intravascular vs extravascular?
intra- 25%, extra 75%
how does total body fluid change with age?
it decreases with age due to shrinkage of extracellular fluid volume
how does total body water relate to total body fat?
it is inversely proportional
how do solute composition and concentration compare in the ICF and ECF?
composition is very different but the concentration is the same (300 mOsm/L)
T or F: kidneys and GI tract are the only effector organs that contribute to regulation of fluid balance.
F- kidneys are the only effector organs in regulation of fluid and water balance
where does unregulated awater and salt loss come from?
sweat, feces and insensible skin and lung loss
what are the four starling forces?
capillary and tissue hydrostatic pressure
capillary and tissue oncotic pressure
why are ions and total osmotic pressure not included in the starling forces?
because ions can readily flow into and out of the vasculature with water
what is the equation for filtration or reabsorption rate? what is Lp and where is it high in the body?
rate= Lp[(Pc-Pi)-(PIc-PIi)]
Lp is the hydraulic conductivity coefficient (high in glomerulus)
what is the interplay between the hydrostatic pressure and oncotic pressure gradients in a normal capillary? what trend of fluid flow does this result in?
hydrostatic forces drive fluid out and oncotic forces drive fluid in. because of the initial filtration of the capillary, there is resorption at the end of the capillary because of the decrease in hydrostatic pressure that has occurred
compare the solute distribution between the ISF and plasma?
they are similar for everything except negatively charged plasma proteins in the vasculature. this drives fluid from the ECF inwards
what is gibbs donnan equilibrium?
the electrochemical equilibrium between the ISF and ESF caused by larger proportion of negatively charged proteins in the vasculature. this causes more cations to diffuse inwards and less anions to do so