6. Cardiac Physiology II Flashcards
Circuits in Series
Flow must be equal
CO of R and L heart are inter dependent bc series arrangement
Hemodynamics
Blood flows in closed system
Blood
- noncompressible fluid
- heterogeneous (plasma, cells, proteins)
Vessels are compliant (flexible), not rigid
-size depends on internal pressure and vascular smooth muscle contractile state
Pressure Profile
BP changes throughout CV system
Heart spends more time in diastole than systole
MAP
Mean arterial pressure
Delta P
change in pressure
largest change in arterioles
Large Artery Properties
Thick walled
Under high pressure
Lots of smooth muscle
Large Vein Properties
Thin walled
Under low pressure
Capillaries
Not a lot of anything (smooth muscle, elastic tissue, fibrous tissue)
Transport processes!
Area and Volume Contained in Systemic Blood Vessels
Biggest cross sectional area: capillaries
(beds not individuals)
Greatest amount of blood: veins
(stretch easily, hold a lot of blood)
Q=delta P/R
Q: flow (how much travels)
- turbulent
- laminar
- velocity (how fast it travels)
delta P: change in pressure
R: resistance
- fluid viscosity
- vessel diameter
- vessel length
v=Q/A
Q: flow
v: velocity
A: total cross sectional area
Tube: pi r squared
If flow through a tube is constant then …
velocity increases as total cross sectional area decreases
Capillaries
Smallest diameter (individually)
Velocity is the least
Total cross sectional area is huge (beds)
Laminar Flow
Ideal
Streamline
Concentric lamina slide past one another
Parabolic effect to flow (highest velocity at center, not much moving on ends)
Predictable
Viscous forces dominate
Turbulent Flow
Eddy currents
Noisy
Larger pressure require to maintain constant flow
Going in all different directions
Large fluctuations in velocity causing swirling effect
Inertial forces dominate
