Cardiac Physiology Flashcards
1
Q
vessels with elastic, smooth muscle, and connective tissue
A
arteries
2
Q
smallest branches of arteries
A
arterioles
3
Q
site of highest resistance to flow
A
arterioles
4
Q
arterial system innervated by the _______ NS
A
Sympathetic
5
Q
single cell endothelium walled blood vessels
A
capilaries
6
Q
site of exchange of nutrients, waste products, (H2O, glucose, CO2)
A
capillary beds
7
Q
vasoactive substance examples
A
epinephrine( will close capillary beds), acids (normal pH 7.4ish), histamine
8
Q
for hives or allergic reaction
A
antihistamines
9
Q
histamine released by
A
mast cells
10
Q
_______ is related to the volume of blood inside a blood vessel
A
capacitance
11
Q
more blood in ______ blood tree than ______
A
venous (64%), arterial
12
Q
Volume/Pressure =
A
compliance
13
Q
if volume of vessel increases with only small changes in pressure that vessel is said to be _______
A
compliant
14
Q
if small change in volume results in large change in pressure, vessel is
A
non-compliant
15
Q
blood vessels vary widely in______
A
compliance– based on vessel wall make-up
16
Q
Veins have much less _______ and ______ than arteries in wall
A
elastin and smooth muscle
17
Q
sympathetic activation of veinous smooth muscle (lower compliance) for purpose of
A
shifting blood to arterial system
18
Q
veins have higher ability to change ________ over arteries
A
capacitance
19
Q
nociceptive afferent fiber synapses on dorsal horn interneuron which synapses on ipsilateral ventral horn motor neurons which excite flexion and inhibit extension of limb (this is reciprocal innervation)
A
withdrawal reflex
20
Q
decreased venous compliance =
A
decreased capacitance
21
Q
for congestive heart failure
A
decrease amount of blood being delivered to heart by makeing veins more compliant w/ nitroglycerin, sodium nitropusside–increases veinous CAPACITANCE and COMPLIANCE
22
Q
nitric oxide is a natural potent
A
vasodilator–to treat angina
23
Q
the tension or stress in the wall of the LV during ejection
A
afterload
24
Q
blood velocity slowest in ________ due to ___________
A
capillaries, large surface area
25
velocity is inversely proportional to ____
area
26
Velocity of blood flow =
flow/ cross sectional area
27
Blood flow Q =
pressure difference P / resistance R
28
more resistance =
less flow (vol/unit of time)
29
Q is inversely proportional to ____
resistance (ex. viscosity of fluid, length/width of vessel) Radius biggest player
30
resistance to blood flow
Poiseulle equation
31
resistance to flow types-- ________ and __________
series and parallel
32
series resistance
Rtotal = R1 + R2 + R3....
33
parallel resistance
1 / Rtotal = 1/R1 + 1/R2 + 1/R3....
34
more open capillary beds =
raise resistance
35
when fluid flows in parallel layers
laminar flow
36
when obstructions build up in vessels
non-laminar flow--makes noises
37
unusual sound blood makes as it rushes past obstruction
bruit
38
lowest pressure that occurs during cardiac cycle
diastolic pressure
39
systolic - diastolic pressure =
pulse pressure
40
volume of blood ejected from the one ventricle on a single cardiac cyclte (heartbeat)
stroke volume
41
volume of blood pumped by heart/ minute.
cardiac output
42
cardiac output =
stroke volume X heart rate
43
highest arterial pressure in cardiac cycle--
systolic pressure
44
systolic pressure happens ____-_______
mid-systole
45
diastolic pressure + 1/3 pulse pressure (estimates mean pressure)
mean arterial pressure
46
memorize mean pressures on outline
*
47
Pressure of aorta/ large arteries
100 mm Hg -- measured with catheter through internal jugular
48
arterioles pressure
50 mm Hg -- on exam numbers will be way off
49
capillary pressure
20 mm Hg
50
Vena cava pressure
4 mm Hg
51
Right atrium pressure
0-2 mm Hg
52
Pulmonary artery pressure
Sys-25 dia-8 mm Hg -- 15 mm Hg mean
53
pulmonary capillaries pressure
10 mm Hg
54
pulmonary vein pressure
8 mm Hg
55
left atrium pressure
2-5 mm Hg
56
the end diastolic PRESSURE that stretches the right or left ventricle of the heart to its greatest geometric dimensions under variable physiologic demand
ventricular preload
57
preload
end diastolic volume of ventricle--measure of optimal actin-myosin arrangement-- related to sarcomere length at end of distole
58
if BP is low and pressure is low it can be assumed that
preload is low and normal saline should be infused
59
RV pressure
15-30 mm Hg
60
LA pressure
6-12 mm Hg
61
dyastoli
ventricle relaxed
62
S1 sound
mitral valve closure
63
S2 sound
aorta/ pulmonic closure---may be split due to vast difference in pressure
64
S2 split
A2 -- aortic 1st (higher pressure)
| P2 -- pulmonic 2nd
65
capacitance vessels
veins
66
specialized myocardial cells for purpose of generation and conduction of depolarization
nodes of heart--SAVe HIS KIN
67
EKG Depolarization of atria
P wave-- SA node
68
Holds SA node stimulation of brief period
AV node--for purpose of complete atrial contraction
69
Depolarization of ventricles
QRS complex--AV node
70
more free intracellular Ca =
stronger heart contraction
71
stimulates intracellular Ca release
Ca induced Ca release--extracellular Ca AP excitation
72
SA resting membrane potential
not stable--decays to threshold 60-100 times/sec --> QRS automatically
its automaticity establishes heart rate
73
sympathetic tone on SA node
make phase 4 steeper--faster heart rate--slide 31
74
parasympathetic activity on heart
make phase 4 flatter--slows heart rate-- slide 31
75
SA node arrest due to
parasympathetic NS tone-- slide 35
76
imp anticholinergic drug
atropine--parasympathetolytic
77
SA node intrinsic firing rate
70-80 BPM
78
AV node intrinsic firing rate
40-60 BPM
79
Bundle of His intrinsic firing rate
40 BPM
80
Purkinje fiber intrinsic firing rate
15-20 BPM
81
examples of when you'd see latent pacemakers "take over" driving heart rate
vagal tone and "heart blocker drugs"
82
Slow depolarization of phase 4 result of
"funny" inward Na+ current
83
"Funny" inward current turned on by
repolarization from the previous action potential--ensures another AP will follow
84
Dopamine's action on heart
speeds up heart rate by stimulating nerve release of norepi
85
If SA node not firing or firing at same time as AV node
"Junctional Rhythm"--no P wave--passive filling of ventricles--20% loss of Cardiac output
86
subunit of troponin
C, I, T -- looked for in blood after MI
87
allows small amount of Ca in to induce Ca release from sarcoplasmic reticulum
VOLTAGE GATED Ca channels
88
voltage change inducing voltage gated Ca channels to open from outside cell
mediated by Na and K as any other cell
89
STRENGTH of heart contraction directly related to
amount of FREE Ca within cell
90
as with skeletal muscle--cardiac muscle must be stretched to ideal length to get
optimal contraction
91
without atrial kick
loss 20% of cardiac output because myocardium not stretched to optimal level pre-systole
92
frank-starling law says
increasing dyastolic pressure raises cardiac output--up to a critical point at which too much stretch from pressure causes not enough actin-myosin (too much preload) overlap and lowers cardiac output
93
aortic pressure
after load
94
ventricular end diastolic muscle fiber length
ventricular preload
95
volume of blood ejected with each beat
stroke volume
96
% of blood in the ventricle at the end of diastole, ejected with a single beat
ejection fraction -- normally 55%
97
cardiac output
stroke volume X heart rate
98
with activity--heart contractility raises in stair step pattern due to
intracellular free Ca not pumped back into SR fast enough
99
Parasympathetic tone only affects
decrease contractility--atria only
100
sympathetic tone will
increase heart contractility--atria and ventricles
101
pickle lady
rapid spike of salt in cardiac system--water follows salt--congestion of blood in lungs because heart can't keep up. veinous backup will cause pt to cough up pink sputum. Overstretched heart, increased afterload because of raised resistance due to sympathetic tone on arteries, acedosis because of CO2 buildup, weakness due to bad blood profusion.
102
central venous pressure related to
left ventricular pressure--> LV volume --> LA pressure--> etc.
103
heart beats per munute
heart rate
104
preload =
ventricular preload
105
stretch of ventricle-- position on frank-starling curve--aka actin-myosin positoning
preload--ventricular end diastolic muscle fiber length--(related to ventricular end diastolic volume or pressure)
106
most important protein in blood contributing to oncotic pressure
serum albumin
107
pressure would raise steeply in LV if
muscle was non-compliant due to prolonged untreated ^ BP--> hypertrophy of muscle = less compliance
108
stroke volume X aortic pressure =
cardiac work
109
cardiac work directly correlated with
O2 consumption
110
volume work for heart MUCH easier than
pressure work
111
Frank-Starling relationship between
pressure and volume
112
Best way to treat ventricular hypertrophy is
make sure it never happens by treating ^BP--Beta blockers, Ca channel blockers--may get resistance from Pt's due to side effects
113
treat volume overload of heart with
diuretics
114
beta-blockers and CCBs
decrease CONTRACTILITY --> decrease myocardial O2 requiremnts --> circumvent angina
115
anti-anxiety drugs i.e. valium may help ^ BP or volume overload by
decreasing sympathetic tone--thereby decreasing myocardial O2 demands
116
arterial side
| venous side
- hydrostatic pressure overpowers oncotic pressure--H2O out
| - oncotic pressure overpowers hydrostatic--pulls water in
117
pickle lady
more solutes in blood pull water into blood --> ^ blood volume--> heart must work harder (might not be able to)
118
components of Starling forces
- capillary hydrostatic pressure (PUSHING pressure w/in cap)
- interstitial fluid hydrostatic pressure (pressure outside cap)
- oncotic pressure (PULLING pressure w/in cap)
- interstitial fluid osmotic pressure
119
alpha 1 adrenergic agonis
constrict ARTERIAL tree--fight or flight (pale w/ fear)
120
______ amount of capillary beds open at any time
small (10-20%) -- brain, heart, kidneys always open--sympathetic
121
parasympathetic NS innervates the
SA and AV nodes--> only atria
122
^ thoracic space --> decrease in pleural pressure
general gas law
123
difference in pressure across something (airway, lung wall, etc) "inside"-"outside" =
transmural pressure--general term (transplural P is subcat)
124
transplural pressure=alveolar pressure - pleural pressure
keeps lungs inflated 0 - (-5) = 5
| -1 - (-7) = 6
