Listen to the apical heart rate at this location

Listen to the apical heart rate at this location.

SLIDE 3
Contraction of the Heart to Pump Blood
The heart's pumping action is sparked by specialized
pacemaker cells and conduction fibers that initiate
spontaneous electrical activity, causing muscle
contractions that result in a heartbeat.
The conduction pathways are located in the myocardium
and transmit the electrical impulse throughout the heart.
The sinoatrial (SA) node is located in the right atrium and
is called the “pacemaker” of the heart because it
normally initiates the electrical impulses.
The atrioventricular (AV) node (or junction) is located in
the lower part of the right atrium.
It relays the impulse from the SA node to the bundle of
His and throughout the ventricles via the Purkinje fibers.
The heart rate and rhythm are influenced by the
autonomic nervous system; factors affecting the
autonomic nervous system can speed up or slow down

the
heart rate.
SLIDE 4
The Cardiac Cycle
The cardiac cycle consists of contraction of the muscle
(systole) and relaxation of the muscle (diastole).
The heart pumps out about 5 L of blood every minute.
The amount of cardiac output depends on the heart rate,
the amount of blood returning to the heart (venous return
or preload), the strength of contraction, and
the resistance to the ejection of the blood (afterload).
Stroke volume equals the amount of blood ejected by a
ventricle during one contraction.
Cardiac output equals stroke volume multiplied by the
heart rate.
SLIDE 8
Blood Flow Throughout the Body

Three types of blood vessels make up the vascular
system:
 arteries
 veins,
 capillaries
These vessels conduct the blood from the body tissues to
the heart –lung circulation and from the heart back to the
tissues.
Arteries carry oxygenated blood away from the heart
Veins carry oxygen-depleted blood back to the heart for
reoxygenation by the lungs
Small veins, venules, and small arteries, arterioles, are
connected by the
capillaries.
It is in the capillaries that the oxygen is transported to
cells and waste products
are removed from them
The aorta is the largest artery in the body, and it receives
blood from the left

ventricle.
The inferior and superior vena cava are the largest veins
in the body and empty
blood into the right atrium of the heart.
Arteries are elastic and accommodate changes in blood
flow by constricting or
dilating.
Three layers of tissue make up the artery wall: The outer
layer (the tunica
adventitia) is connective tissue
The middle layer (the tunica media) is smooth muscle;
and the inner layer (the
tunica intima) consists of endothelial cells.
SLIDE 9
Veins have the same three layers but with less smooth
muscle and connective
tissue.

The veins are thinner and less rigid and thus can hold
more blood.
The heart pumps blood through the arterial system with
each contraction.