Intro To Renal Physio Flashcards
(42 cards)
What are the regulatory functions of the kidneys?
- ECF volume, osmolarity, ion composition
- clearance of metabolic end products, toxins, and drugs
- endocrine (erythropoietin, D3, renin)
What system does the kidney play an intergral role in and why?
cardiovascular; adequate BP and flow
In the standard patient what is the TBW, ICF, and ECF volumes?
42L, 28L, 14L
What are the Intravascular fluid and extravascular fluid?
plasma and interstitial fluid (75% of ECF)
TBW ____with age
decreases
TBW is ______proportional to body fat.
inversely
The solute composition of ECF and ICF are ______, the osmolarity of ICF and ECF is the _____
different; the same
Monitoring the volume and osmolarity of the _____ maintains TBW and osmolarity due to water and solute exchange between ECF and ICF compartments
plamsa
What effector organ controls regulated salt and water excretion? How is this accomplished?
kidney; they respond to the amts of solute and water consumed by increasing or decreasing the amounts of solute and water in the urine
what are some sources for unregulated water and salt loss
sweat, feces, insensible skin and lung loss
What determines fluid balance between plasma and ISF?
balance between capillary hydrostatic pressure and osmotic pressure differences across the capillary walls
What do the capillary hydrostatic pressure and oncotic pressure at the arteriolar end? Does this result in filtration or absorption?
Pc high, oncotic low–>filtration
What do the capillary hydrostatic pressure and oncotic pressure at the venous end? Does this result in filtration or absorption?
Pc low, oncotic higher–>reabsorption
What is responsible for the reversal driving force at the venous end?
filtration of fluid from intravascular to extravascular compartment decreases the hydrostatic pressure and concentrates the plasma proteins, which increases intravascular oncotic pressure.
Why is the oncotic pressure in the plasma higher than that in the ISF?
there’s more protein in plasma
What is Gibbs-Donnan equilibrium?
presence of negatively charged proteins in plama leads to higher cation concentration in plasma and higher anionic concentration in ISF
Why is the rate of filtration much higher in the glomerulus than in the systemic capillaries?
glomerular capillaries have a higher hydraulic conductivity
What is edema?
excess accumulation of fluid in the interstitial space due to cardiac, renal, hepatic, or endocrine dysfunction
-it is a localized or generalized imbalance in hydrostatic and osmotic pressure across the capillary wall; induces the fluid shift from intravascular to extravascular space
Why are CHF, nephrotic syndrome, and liver disease important?
cause isotonic rentention of sodium and water as well as decreased circulating volume–>decrease renal perfusion–>increase sodium rentention maintaining the edema
How can edema be assessed clincially?
increase in edema–>increase in weight;
decrease in edema–>decrease in weight
Net movement of water is driven only by
osmotic pressure differences across the cell membrane
Water moves (active or passive)____ down its concentration gradient in a direction from the side of higher water concentration to the side of lower water concentration `
passively
What is the rule of water movement?
passive transport of water follows active or passive transport of solutes
What happens when you have isoosmotic fluid expansion (ie IV isosmotic fluid gain to ECF)?
increase in ECF,
- N/C n ECF osmolarity
- no osmotic driving force between ICF and ECF
- no change in ICF volume or osmolarity
- dilution of plasma proteins and decrease Hct
