Cardiology Flashcards
The resting membrane potential for the cardiac muscle cell is about _____mV. The change in membrane potential when an AP occurs is aboout _____ mV
-90
105
The plateau in the cardiac action potential is ________secs long which is _____ longer than skeletal muscle
.2
15
The 3 main ions responsible for the cardiac AP are _____ (wants to be at 120mV), ______ (wants to be at 67mV), and _____ ( wants to be -90mV)
Ca
Na
K
The threshold for an action potential is ______ mV.
-70mv
The plateau allows for _________ and ____________ of the heart.
Filling and contraction
The increase in________ ions and decrease in ________ ion permeability cause the cardiac AP plateau.
Ca++
K+
Preventing outflow of ______ takes cell longer to reach RMP.
K
The velocity of excitatory fibers in the atria/ventricles is _____- _____m/sec. It is 1/10th the velocity of skeletal muscles due to the ____ channels being slower. This allows time for _______ to develop.
.3 - .5m/sec
Na
TENSION
The ________________ allows for cardiac rest but another AP can come along and cause another depolarization … it will just need a bigger ___________ though.
Relative refractory period
stimulus/ potential
The heart will not pump as well with an AP generated during the _______________ period.
Relative Refractory
During the ____________ period, no contraction can occur. This correlates to the ___________. The membrane is too ____________.
Absolute refractory
Ca++ plateau
positive +
The AP in the heart is generated by the _____ or ______. It then travels into the __________ where depolarization causes extracellular ______ ions to enter the cell.
SA or AV node
T Tubule
Ca++
The increase in intracellular Ca++ is detected by Ryanodine receptors in the ____________ which causes ________ to be released. This is called the ______________.
Sarcoplasmic Reticulum
more Ca++
Calcium Spark
The T-tubules in the heart are ________ times the size than in skeletal muscle. In cardiac muscle the T Tubules open directly into the ________________ fluid, so their ________ concentration depends highly on extracellular concentration
5
extracellular
Ca++
In cardiac cells, there is a slight delay between_________ and _________.
Excitation and contraction
The__________ node is the pacemaker of the heart. The ________ delays conduction through the heart which allows for ___________ contraction
SA
AV
atrial
In cardiac cells, the wave of depolarization propagates to adjacent cells via ________________ located on ________________.
Gap Junctions
Intercalated Disks
The AV valves are only completely shut during ______________.
Ventricular Systole
On your CVP, the ______ wave shows you how well the atria are contracting. This correlates to _____ % of your stroke volume
A
20%
The most sensitive organ to perfusion is the ______________
Kidney
The Four phases of the pressure volume loop are: ____________, ____________, __________, ____________
Filling, Isovolumic contraction, Ejection, Isovolumic Relaxation
At End diastolic, the AV valves will _________ and you will start the ____________ contraction
Close
Isovolumic
At the end of the isovolumic contraction, the _________ valve will open and you will start the _________ phase. The
atrial
Ejection
The pulse pressure can be measured on the P-V loop by subtracting the ________________ from the _________________.
start of the ejecting phase pressure
peak of the ejecting phase pressure
S1 heart sound would be heard at ______________ on the PV loop and S2 would be heard at ________________
End Diastolic (mitral valves closing) End Systolic (aortic valve closing)
The End systolic volume will be around ________ in a healthy heart.
50ml
The Stroke volume represents “___________” and can be measured on the PV loop by subtracting start of __________ from the end of ________ phase on the loop.
Net-Work
Filling
filling
The average stroke volume will be around _____ ml. The ejection fraction is the stroke volume divided by ________ and the average will be around _______.
65ml/beat
peak volume
60%
Name the cardiac pressures RA: RV: PA: LA: LV:
4 25 25/10 8-10 80-100
About _____% of ventricular filling occurs during diastole before contraction of the atria. The remaining is called the ___________.
75
atrial kick
The ____- wave is atrial contraction
The ____-wave is ventricular contraction
The ____-wave is the in-filling of the atria from venous return.
A
C
V
The fraction of the end-diastolic volume that is ejected is the _____________. It is normally 110-120ml.
ejection fraction
What 3 things affect stroke volume?
Preload, afterload, Contractility
Excess _______ ions will cause dilation of myocardium. Excess _______ ions will cause spastic contractions.
Potassium
calcium
The sympathetic NS effects on the heart will be to _____________ & ________________
Increase HR and Contractility
The sympathetic NS ___________ contractility by stimulating _______ receptors
Increases
Beta
Most of the sympathetic NS innervates the _____________, while the Parasympathetic goes to the ____________
ventricles
atria(SA& AV nodes)
_________ is calculated with End Diastolic Pressure
Preload
Preload is affected by _________ and rate of ______________.
Venous BP
Rate of venous return
______________ is the pressure the ventricle must generated to EJECT blood.
Afterload
Cardiac Output at rest is __________.
4-6L/min
_________ are the last small branches of arteries. They are the ____________ and can vastly change blood flow.
arterioles
control conduits
___________ is where the exchange of fluids, nutrients, and O2 occurs
Capillaries
________ collect blood from capillaries and _______ are the major conduit of transport of blood to the heart
venules
veins
___________ are the major reservoir of blood in the body
Veins