Renal Phys 1 Flashcards
(32 cards)
What are the three body fluid compartments?
ICF, ECF, other (transcellular)
How much of the total body fluid is ICF?
40% or 2/3
How much of the total body fluid is ECF?
20% or 1/3
What are the two components of ECF?
plasma and interstitial fluid
Does interstitial fluid or the plasma make up more of the ECF?
interstitial fluid
Which has a higher concentration of proteins, interstitial fluids or plasma? Why?
plasma, because proteins cannot cross the capillary membrane easily
Which component can you use to regulate volume?
the plasma
Water added to the body first enters and leaves through which compartment?
ECF
What is the Gibbs-Donnan effect?
Since there are more negatively charged proteins in the plasma, cations will enter the plasma due to their attraction to the negative charge and anions will remain in the interstitial fluid. This creates an osmotic and electrochemical gradient across the membrane
How do you counteract the Gibbs-Donnan effect?
the Na/K ATPase counteracts this force by pumping 3 sodium out, which will allow water to follow.
What is third spacing? What is its clinical relevance?
Third-spacing occurs when too much fluid moves from the intravascular space (blood vessels) into the interstitial or “third” space-the nonfunctional area between cells. This can cause potentially serious problems such as edema, reduced cardiac output, and hypotension.
What is the primary ECF cation? Anion?
Na+ ; Cl-
What is the primary ICF cation?
K+ ; phosphate
Why can electrolytes cause greater fluid shift?
because of their high osmotic power; they can dissociate in water to at least two ions
How do osmolality and osmolarity differ?
Osmolality measures osmotically active particles per kg of water, while osmolarity measures the particles per liter of total solution
Describe the compartmentalization of fluids in blood
Blood has both ECF (plasma) and ICF (RBC); about 60% of blood is plasma and 40% is RBC
What is hematocrit and what are the normal values for men and women?
It is the fraction of the blood that is RBC;
men 0.40
women 0.36
How does ECF volume loss change total plasma protein (concentration) and hematocrit?
It increases the concentration and increases hematocrit
How does ECF volume gain change total plasma protein (concentration) and hematocrit?
decreased total plasma protein (dilution) and decreased hematocrit
What causes fluid to leave the capillary?
Hydrostatic pressure
What causes fluid to enter the capillary?
plasma colloid osmotic pressure - pulling force of albumin attracting water into capillary
What are the two causes of edema?
- alteration in capillary hemodynamics (starling forces)
2. inappropriate renal retention of dietary Na+ and water expansion of ECF volume
What are the three types of solution tonicity? What are the differences?
Isotonic, hypertonic and hypotonic.
Isotonic environment has a NaCl concentration = .85%
Hypertonic environment has a NaCl concentration > 0.85%
Hypotonic environment has a NaCl concentration < 0.85%
what are the two types of replacement therapy?
Colloid and Crystalloid. Colloids are infused and remain in the capillaries and draw fluid into vessels. Crystalloids contain organic or inorganic salts and do not cross plasma membranes (remain in ECF).
