Chapter 3: Cardio (not everything, mainly equations) Flashcards
Velocity of blood flow can be expressed as
V= Q/A
Q= Flow ( mL/Min) A= Area (cm^2)
As blood flow goes up so does velocity.
As cross sectional area goes up, velocity decreases. (Low in capillaries since they have the largest cross sectional area)
Q = dP/R
Flow = Change in Pressure / Resistance (TPR)
dP= MAP -Right Atrial Pressure
Analogous to ohms law: I (flow) = V(voltage or Pressure) / R (resistance)
Poiseulles law
To determine Resistance
R = (8 x Viscosity x Length) / pi x r^4
In this, changes in radius have the larges effect on resistance.
The larger the radius the less resistance (by exponent 4)
Really just remember R= Viscosity x L / R^4 (the other crap won’t change but these will)
Is resistance in the vascular system in series or in parallel ?
Parallel (like the capillary bed)
With excetption of going from one organ to the next (series), blood flow is set up in parallel
Blood flow where there is no leading edge, fluid moves in a solid wall
Laminar
When Reynolds Number is increased, is there an increased or decreased chance of turbulence ?
Increased
As blood viscosity decreases, is there an increase or decreased chance of turbulence ?
Increased
As velocity of blood flow decreases is there an increased or decreased chance of turbulence ?
Decreased
Capacitance
The distensibility of a vessel (ability of a vessel to accommodate increased volume with minimal increases in pressure)
C= V/P
Capacitance = Volume/ Pressure
decreases with age
Is capacitance higher in veins or arteries ?
VEINS (of course, did i really need to ask ?)
Where in the vascular system is the decreases in blood pressure most pronounced ?
Across the ARTERIOLES !
Aorta: 100 mmHg
Arterioles: 50 mmHg
Capillaries: 20 mmHg
Vena Cava: 4 mmHg
Pulse Pressure
Systolic - Diastolic
Mainly determined by STROKE VOLUME
Decreases in capacitance leads to pulse pressure increases
MAP
Diastolic + 1/3(Pulse Pressure)
Pulse pressure = Systolic - Diastolic
P Wave
Atrial Depolarization
Atrial Repolarization
Burried in the QRS
PR interval
Beginning of P-wave to beginning of Q
R = QRS complex, they just don’t want to say it.
PR interval varies with conduction velocity through the AV Node
QRS Complex
Depolarization of the Ventricles
QT Interval
Beginning of the Q wave to the End of T-wave.
Represent Ventricular Depolarization and Repolarization
ST Segments
End of the S-wave to the beginning of the T-wave
T-wave
Ventricular Repolarization
What ion determines the resting membrane potential ?
K+ (the equilibrium potential of -94 is close to resting membrane potential)
In general, inward current of ions should _______ the cell
depolarize ( I, know this isn’t necessarily true, only with Cations)
Outward flow generally hyperpolarizes the cell
Phase 0 is mediated by opening of which Voltage Gated channel ?
Na+ ( leads to an inward current) and depolarization of cell
Phase I is mediated by
Brief depolarization when Na+ gates close and K+outflow