pathophysio Flashcards
1
Q
Muscle fibers surrounding the heart are oriented ____ which allows ____.
A
- circular, longitudinal, oblique
- blood to be squeezed from apex to base
2
Q
cardiac output =
A
HR x SV
volume per min
3
Q
flow
A
Q =∆P/R
4
Q
mean arterial pressure
A
DP + [(SP-DP)/3]
5
Q
myocardial cell types
A
- pacemaker: automatically depolarize
- non-pacemaker (majority): depolarize when stimulated
6
Q
pacemaker cell potentials consist of:
A
- phase 4 depolarization: slow rise to threshold
- action potential
- repolarization
7
Q
phase 4 depolarization involves:
A
- decreased outward flow of K
- **funny current influx of Na
- gradual influx of Ca as threshold approached
8
Q
myocyte depolarization involves:
A
- vg Ca channel opening and influx of Ca
9
Q
myocyte repolarization involves:
A
- Ca channels close
- K channels open
10
Q
PNS ____ HR by ____.
A
- slows
- slowing hyperpolarization and slowing phase 4 (decreased If ICa)
11
Q
SNS ____ HR by ____.
A
- increases (also force)
- increases phase 4 rate (increased If and ICa) and decreasing threshold
12
Q
+ ionotropic effect
A
- increase HR and force of contraction due to increased intracellular Ca
13
Q
non-pacemaker cell action potential
A
- phase 0: rapid influx of Na
- phase 1: inactivation of Na channel and open K channel
- phase 2: plateau (Ca K balanced); Ca influx, slow K out
- phase 3: Ca close, K predominates
- phase 4: resting phase
14
Q
the slowest conduction velocity
A
travels through the AV node
15
Q
P wave
A
- atrial depolarization following SA node firing
16
Q
QRS complex
A
- ventricular depolarization
- atrial repolarization
17
Q
T wave
A
- ventricular repolarization
18
Q
PR segment
A
- time to pass through AV node
19
Q
QT interval
A
- duration of ventricular AP
20
Q
normal axis:
left axis deviation:
right axis deviation:
A
-30 to +90
< -30
> +90
21
Q
pulmonary wedge pressure estimates
A
- left atrial pressure
22
Q
ventricular systole begins with ____ and ends with ____.
A
- mitral valve closure
- aortic valve closure
23
Q
atrial pressure waves
A
- a: atrial systole
- c: mitral valve closure
- v: atrial filling and emptying
24
Q
stroke volume =
A
EDV-ESV
25
end diastolic volume
- volume in ventricle just before contraction
26
end systolic volume
- volume in ventricle right after contraction
27
S1
- closure of mitral and tricuspid valves
| - c wave
28
S2
- closure of aortic and pulmonic valves
29
S3
- diastolic; kentucky
| - during rapid filling, v wave
30
S3
- diastolic; tennessee
| - vibration of ventricular walls in atrial contraction, a wave
31
systolic murmurs
- aortic/pulmonary stenosis, mitral/tricuspid regurgitation, VSD
32
diastolic murmurs
- aortic/pulmonary regurgitation, mitral/tricuspid stenosis
33
continuous murmurs
- patent ductus arteriosis
34
L heart pressures are ____ than R heart pressures.
greater
35
pressure volume loop: axes
- x: left ventricular volume
| - y: left ventricular pressure
36
pressure volume loops: phases
* moves counter clockwise
- a: ventricular filling (mitral valve open/close)
- b: isovolumetric contraction
- c: ejection of sv (aortic valve open/close)
- d: isovolumetric relaxation
37
pressure volume loop: width and area
- width = SV = EDV-ESV
| - area = stroke work = SV * MAP
38
ejection fraction
SV/EDV
39
SV is affected by
- preload (increases EDV and Sv)
- afterload (increase ESV, decreases SV)
- contractility (inotropy) (decreases ESV, increases SV)
40
preload
- stretch of cardiac myocyte prior to contraction
| - maximized at EDV
41
heterometric regulation
- regulation of cardiac function via changing sarcomere length (i.e. preload)
42
afterload
- load against which heart muscle contracts to eject blood (aortic or pulmonary pressure and ventricular wall stress)
43
homeometric regulation
- regulation of cardiac function independent of sarcomere length (i.e. afterload)
44
positive inotropic effects result from:
- increased rate of delivery of Ca to myofibrils
- increased binding of Ca to troponin c
- increased rate of cross-bridge cycling
- increased HR (increased Ca)
45
loss of arterial compliance means that systolic pressure ____ and capillary flow ____.
- rises
| - becomes pulsatile
46
largest pressure drop is associated with ____. 3 functions are:
- arterioles
- reduce blood pressure at capillary entrance
- distribution of blood flow between/within tissues
- dampens pressure pulses
47
autoregulation allows:
- local/regional control of blood flow without ANS involvement
- so tissue blood flow remains constant in spite of arterial pressure changes
48
distribution of blood flow between tissues is aided by:
- muscular walls of arterioles
- metarterioles
- precapillary sphincters (direct blood flow)
49
causes of edema
- increased venous pressure (hydrostatic)
- decreased blood osmotic pressure
- increased interstitial osmotic pressure
50
factors that increase O2 demand of heart
- increased afterload
- increased SV
- increased HR
51
How is O2 delivery to heart increased?
- increasing coronary circulation
| - autoregulation with adenosine
52
coronary blood flow in left ventricle occurs primarily during ____.
- diastole
53
velocity varies ___ with total cross sectional area. slowest velocity is in ____.
- inversely
| - capillaries
54
ERP
- plateau phase
- limits frequency of AP and avoids tetany
- allows for ventricular filling
55
Frank-Starling curve
- x-axis: preload, EDV, EDP, sarcomere length, venous return
| - y-axis: contractile force, SV
56
baroreceptor signaling functions between MAP of:
- 75-150 mmHg
57
response to increased O2 demand
- increased afterload
- increased SV
- increased hr
