applied phys exam 2

pressure exerted on inside of capillary walls by blood which pushes fluid out of capillary into interstitial space

Capillary hydrostatic pressure (P_C)

force caused by dispersion of plasma proteins and pulls water into capillaries

Plasma-colloid osmotic pressure (π_P)

pressure exerted on outside of capillary walls by ISF, pushes fluid from interstitial space to capillary

Interstitial fluid hydrostatic pressure (P_IF)

force caused by plasma proteins that leak into ISF (negligible in normal conditions)

Interstitial fluid-colloid osmotic pressure (π_IF)

what are the outward pressures?

Pc and π_IF

what are the inward pressures?

π_P and P_IF

___% is ICF

40%

___% is ECF

20%

___% of body weight is water

60%

___% of ECF is plasma, so its __% of total body weight

20%; 4%

___% of ECF is interstitial fluid, so its __% of total body weight

80%; 16%

indicator for TBW

radio-labeled water

indicator for ECF

inulin (can cross capillary walls but cannot enter cells)

indicator for plasma

albumin (Large protein that remains in plasma and doesn’t cross capillary walls)

C=

M/V

M=mass
V=volume

net exchange pressure equation:

NEP=(PC​+πIF​)−(πP​+PIF​)

Basically outward minus inward pressure

Positive NEP means ultrafiltration

Negative NEP means reabsorption

EF (percentage of end-diastolic volume (EDV) that leaves the heart)=

SV/EDV

Poiseuille’s Law:

Q = πΔPr⁴ / 8ηL

1. Q = flow

2. ΔP = pressure gradient

3. r = vessel radius

4. η = viscosity

5. L = vessel length 

   1. ↑ pressure → ↑ flow

   2. ↑ radius → ↑ flow

   3. ↑ viscosity → ↓ flow

   4. ↑ length → ↓ flow

PP (pulse pressure) driven by:

SV (↑ PP) and compliance (↓ compliance → ↑ PP)

MAP driven by

 CO and TPR

DP most sensitive to

TPR and HR

SP most sensitive to

SV and compliance

which has higher pH: arterial or venous and what are they?

arterial is 7.45 while venous is 7.35

pH=

6.1 + log ( [HCO₃⁻] / (0.03 × PCO₂) )

most important buffer?

protein

majority of bicarb reabsorption happens in?

proximal tubule

why is compensation for metabolic alkalosis not that effective?

compensation is respiratory acidosis which means we decrease respiratory rate and retain CO2 but since we are holding breath we do not breathe in O2 which is a problem

anion gap? only useful in?

difference between measured cations in ECF (primarily sodium) and anions (bicarb and chloride)
-useful in metabolic acidosis