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"right" vs "left" side circulation
right = pulmonary (deoxygenation)
left = systemic (oxygenated)
flow is proportional to pressure & inversely proportional to resistance
ohm's law
↑ resistance = ____ CO
↓
↑ flow = ____ pressure
↑
↑ length = ____ resistance
↑
↓ radius = ____ resistance
↑
what impacts flow the most
radius!
compliance
distensibility of a structure
(pressure will stay the same if more blood enters)
exitation-contraction coupling
1. pacemaker cells = AP along T tubules
2. voltage-gated ion channels = Ca2+ INTO cell
3. SR releases Ca2+
4.Ca2+-induced Ca2+-released
5. Ca2+ to troponin C...
6. Ca2+-ATPase = put Ca2+ back into SR
Ca2+/Na exchanger = Ca2+ OUT of cell
Conduction pathway of the heart
SA node, AV node, bundle of His, L/R bundle branches, and Purkinje fibers
ventricular muscle AP (phases)
Phase 0 = Na+ - depol
Phase 1 = K+ leaves - partial repol
Phase 2 = Ca2+ comes in same time K+ leaves - plateau
Phase 3 = K+ leaves - repol
(Phase 4 = rest)
SA node will fire spontaneously during which phase?
Phase 4
EKG wave meanings
P = atrial depol (contraction)
QRS = ventricular depol (contraction)
T = ventricular repol (relaxation)
normal rate of SA node. What slows it down?
100 bpm
- pns tone = 70 bpm
what happens if SA node fails?
AV node 40-60 bpm
- if fails = bundle of his = 20-40 bpm
AV node must have a long ______ = protect against arrhythmias
absolute refractory period
(beta blockers extend this period if used)
atrial fibrillation rate
350-600 bpm (thats why we need AV node to relax HR)
PNS vs SNS chronotropic (beats per min) effect
- what do they release?
PNS = negative chronotropic effect
- Ach -> muscarinic
SNS = positive chronotropic effect
- E/NE -> adrenergic (a,beta)
what drug is used for bradycardia?
atropine = blocks muscarinic receptors (↓ pns)
inotropy vs dromotropy vs chronotropy
inotropy = force of contraction
dromotropy = conductance
chronotropy = bpm
leads:
- frontal plane
- transverse plane
frontal = 6 limb leads
transverse = 6 precordial leads
ventricular diastole
atrial systole
isovolumic ventricular contraction
ventricular ejection
isovolumic relaxation
ventricular diastole = AV valves open
atrial systole = atrial kick
isovolumic vent contraction = aortic valve open, AV valves closed
ventricular ejection = ventri p > aortic p (120mmHg)
isovolumic relaxation = ventri p < aortic p, aortic valve closes, AV valves open
dicrotic notch
vibration (backflow) caused by closure of aortic valve = change in aortic pressure
A, C, V wave in left atira
A = atrial systole
C = mitral valve closes in vent cont
V = atrial filling in vent diastole
stroke volume equation
SV = EDV - ESV
ejection fraction equation
EF = SV/EDV
ejection fraction is usually ___ %
55-65%
S1
lub" = AV valves close
S2
- s2 split
"dub" = semilunar valves close
- inspiration = S2 split (↓ pressure = ↑ SV), delays P2 (pulomonic valve)
S3
"Tennessee" = blood hitting stiff ventricle
S4
"kentucky" = atrial kick
CO equation
Q = HR x SV
2 forms of congestive heart failure:
Preserved EF vs Reduced EF
preserved = diastolic dysf
reduced = systolic dysf
Cardiac Index equation
CI = Q/BSA (body surface area)
- only used in icu
Frank-Starling Law
- give relationships
- why does this occur
↑ stretch = ↑ EDV = ↑ contraction = ↑SV
there is increased sensitivity of troponin C to Ca2+!
____ is the MOST important determinant of SV
EDV!!!
Preload vs. afterload
Preload = EDV created by venous return
Afterload = systemic/aortic pressure
5 factors that increase preload
1. ↑ circulating blood
2. skeletal muscle contr
3. inspiration (increase abdominal pressure -> blood to heart)
4. atrial systole
5. venoconstriction
SV is determined by what 3 things?
preload, afterload, contractility
↑ preload = ____ SV
↑
2 factors that increase afterload
1. low compliance of ventricle
2. stenosis
use BP to test vascular resistance
↑ afterload = ____ SV
↓
left vs right-shift in Frank-Starling
left = ↑ contractility
right = ↓ contractility
↑ compliance = ____ SV
↑
LV failure = ___ compliance = ___ pressure = ___ EDV = ___ SV = ___ HR
↓ compliance = ↑ pressure = ↓ EDV = ↓ SV = ↑ HR
site of greatest vascular resistance ??
arteries & arterioles
they control BP the most!
benefit of capillaries
large surface area = exchange of nutrients
benefits of venules/veins
high capacitance (can hold a LOT of blood), low pressure
↑ venous tone (aka venoconstriction) = _____ venous return
increase
↑ SVR = ___ afterload = ____ SV
↑ afterload = ↓ sv
what 2 things affect ESV
1. afterload
2. contractility
!!!
what effects EDV
preload !!!
Pulse pressure equation
PP = SBP-DBP
MAP equations
MAP = DBP + 1/3 (PP)
MAP = CO x SV
what 4 things det SBP
1. MAP is proportional to CO & SVR
2. Increases in SV = increase SBP & PP
3. low aortic compliance = high SBP (atherosclerosis)
4. DBP
↑ CO & ↑ SVR = ___ MAP
↑
↑ SV = ___ SBP = ___ PP
↑ SBP = ↑ PP
↓ compliance = _____ SBP
↑
what 3 things det DBP
1. vascular resistance
2. runoff from aorta
3. time
↑ vascular resistance = ___ DBP
↑
↑ runoff = ___ DPB
↑
↑ HR = ____ DBP
↑ (less time for drop in pressure)
SVR is what
systemic vascular resistance (aka total peripheral resistance!!)
How is SVR determined?
vasoconstriction
vasodialation
vasoconstriction = ____ SVR = ___ afterload = ____ SV
↑ SVR = ↑ afterload = ↓ SV
vasoconstriction = ____ VR
↓
vasodilation = ____ SVR = ___ afterload = ____ SV
↓ SVR = ↓ afterload = ↑ SV
vasodilation = ___ VR
↑
Central venous pressure (CVP) is pressure of blood in the _____
right atria !!!
(& vena cavas)
what do you do when CO is LESS THAN 5???
add saline!!!
ON EXAM
↓ CVP = ___ venous return
↑
↑ CVP = _____ venous return = ____ EDV = ___ preload = ___ SV
↓venous return = ↓ EDV = ↓ preload = ↓ SV
3 ways venous return can be altered
1. supine -> standing
2. skeletal muscle contr
3. ventilation
supine to standing = ____ VR = ___ CO = ___BP
↓ all
walking = ____ VR = ____ CO = ___ BP
↑ all
inspiration = ____ VR = ____ CO
↑ both
transmural pressure
pressure able to distend or dilate a structure
CO must equal
VR (venous return)!!
issues with filling vs contraction
filling = diastolic problem
contraction = systolic problem
HR is ONLY determined by?
PNS -
SNS +
main response system that protects against systemic arterial BP
baroreceptors!
primary site of cardiovascular control
medulla oblongata
PNS (vagal) fibers innervate...
SA, AV, conduction pathways, cardiac myocytes
PNS fibers main effects
lower HR, conduction, & contraction
SNS have which receprots
beta & alpha
SNS receptors:
B1
A1
B2
B1 = ↑ HR, conduction, contractility
A1 = vasoconstriction/venoconstriction
B2 = vasodilation
net effect of SNS is ___ & ___!!
vasoconstriction & ↑SVR
NE vs E affinity for SNS receptors
NE - alpha
E - B2
baroreceptors: primary vs secondary
primary = carotid sinus (glossopharyngeal CN IX)
secondary = aortic arch (vagus CN X)
carotid message = _____ stretch = activates ____ nervous system = ____ tachy
↑ stretch = activates PARASYMPATHETIC nervous system = ↓ tachy
veno vs vasoconstriction
veno - ↑blood flow
vaso - ↓blood flow
see if a change BP/HR is due to a change of position causing fainting - a good baroreceptor reflex test!
tilt-table test
need constant blood flow
brain & kidney (unlike GI)
when is blood flow highest in the myocardium?
diastole!!!
which is why tachy is an ISSUE (less diastole)
how do you increase O2 supply?
increase coronary BF
what drug provides vasodilation
nitroglycerin = has nitric oxide
myogenic autoregulation
brain will have constant supply of O2
want MAP to be ____
>65mmHg!!!
How is renal & GI affected during exercise?
vasoconstriction
(SNS - don't want to pee/eat while running)
SNS - when cold vs hot
cold = vasoconstriction
hot = vasodilation
Note 
Flashcard (42)