Perfusion (Heart) Flashcards
(136 cards)
diastole:
period of ventricular relaxation resulting in ventricular filling
myocardium:
muscle layer of the heart responsible for the pumping action of the heart
cardiac conduction system:
heart cells responsible for generating electrical impulses to the myocardial cells
The four valves in the heart, open and close in response
to the movement of blood and pressure changes within the chambers
There are two types of valves:
atrioventricular (AV) and semilunar.
the sinoatrial (SA) node
(the primary pacemaker of the heart)
atrioventricular (AV) node
(the secondary pacemaker of the heart)
The SA node in a normal resting adult heart has an inherent firing rate of
60 to 100 impulses per minute
the AV node has the second-highest inherent rate (
40 to 60 impulses per minute)
the ventricular pacemaker sites have the lowest inherent rate
(30 to 40 impulses per minute)
If the SA node malfunctions,
the AV node generally takes over the pacemaker function of the heart at its inherently lower rate.
Should both the SA and the AV nodes fail,
a pacemaker site in the ventricle will fire at its inherent bradycardic rate of 30 to 40 impulses per minute
The heart is composed of how many layers
three layers
The inner layer, or endocardium,
consists of endothelial tissue and lines the inside of the heart and valves.
The middle layer, or myocardium,
is made up of muscle fibers and is responsible for the pumping
The exterior layer of the heart is called
epicardium
The pumping action of the heart is accomplished by
the rhythmic relaxation and contraction of the muscular walls of its two top chambers (atria) and two bottom chambers (ventricles).
During the relaxation phase, called diastole, all four chambers relax simultaneously, which allows
the ventricles to fill in preparation for contraction.
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The right side of the heart, is made up of
the right atrium and right ventricle,
the right side of the heart distributes venous blood (deoxygenated blood) to
the lungs via the pulmonary artery (pulmonary circulation)
The pulmonary artery is the only artery in the body that carries
deoxygenated blood.
The left side of the heart, composed of
the left atrium and left ventricle
the left side of the heart distributes
oxygenated blood to the remainder of the body via the aorta