17 Questions
The increase in ______ level inside the muscle fibers leads to an increase in the force of contraction.
Ca2+
Digitalis inhibits the ______ pump, leading to an increase in intracellular Na+.
Na+ K+
The Na+/______ exchanger is prevented from pumping Ca2+ to the extra cellular fluid.
Ca2+
Cardiac output (COP) is defined as the volume of blood pumped by each ______ per minute.
ventricle
The stroke volume is the volume of blood pumped by each ______ per beat.
ventricle
The volume of blood in a ventricle at the end of contraction, or ______, is called end-systolic volume.
systole
The volume of blood in the right and/or left ventricle at end load or filling in ______ is called end-diastolic volume.
diastole
The number of heart beats per ______ is called heart rate.
minute
The parasympathetic stimulation has a ______ chronotropic effect on the heart rate.
negative
The greater the ______ the greater the stretch of the cardiac muscle fibers.
EDV
More intracellular ______ means stronger contraction.
Ca2+
The chemical transmitter that acts on ß1 receptors is ______.
NE
The type of receptors that norepinephrine acts on is ______.
ß1
The level of ______ in the cytosol determines the strength of cardiac muscle contraction.
cytosolic calcium
The type of Ca2+ channels that open due to norepinephrine is ______ type.
L-
The type of effect that catecholamines have on ventricular contraction is ______.
positive inotropic
The second messenger molecule that increases due to norepinephrine is ______.
cAMP
Test your knowledge of cardiac physiology, including the effects of digitalis on muscle contraction and ion transport. Learn how Ca2+ levels and Na+ gradients impact cardiac function.
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