Cardiac Review Flashcards
Cardiac muscle cells are connected via _________
intercalated disks
Extracellular ____ is essential for contraction of cardiac muscle
Ca2+
T/F: You cannot increase the force of contraction in cardiac cells by recruiting ore muscle fibers or by inducing tetany
TRUE
_______ is related to heart rate
Chronotropy
What is dromotropy?
conduction velocity
What is inotropy?
force
What is clinotropy?
rate (velocity) of contraction
What is lusitropy?
rate of relaxation
More blood volume is contained in the _____ than ______
veins
arteries
What has the highest cross-sectional area?
capillaries
If vascular resistance is in a series, then it is [additive/reduced]
additive
If vascular resistance is in parallel, then it is [additive/reduced]
reduced
What does Reynold’s number indicate?
turbulence
The [higher/lower] viscosity of a fluid, the more resistance it will have
lower
What is the definition of cardiac output
Q = P/V
What is preload?
ventricular wall stretch prior to contraction
- proportional to EDV
What is afterload?
the forces that oppose the ventricular ejection of blood
Preload is when the _____ valve closes
mitral
Afterload is when the _____ opens
aortic
What is isovolumentric contraction
AV valve is closed
What is the mean pressure of the aorta?
100 mmHg
Is diastole or systole longer?
diastole
What is the windkessel effect?
the proximal large arterial vessels store approximately 50% of the left ventricular stroke volume during systole
elastic forces of the aortic wall propel this volume to the peripheral circulation during diastole
What is the importance of intercalated discs, fascia adherens, and desmosomes?
discs: ensure that cardiac muscle functions as a single unit
adherens & desmosomes: transmit force from one cardiac muscle cell to another
What is effective refractory period?
period during which the membrane is not sufficiently depolarized and sodium channels have no completely recovered
- non-conducted electrical response to stimulus
What is relative refractory period?
requires a larger stimulus
What are the 3rd and 4th heart sounds?
3rd: ventricular filling
4th: atrial filling
