Anatomy of the Heart
Your heart is located under the ribcage in the
center of your chest between your right and left lung. Its shaped like an
upside-down pear. Its muscular walls beat, or contract, pumping blood
continuously to all parts of your body.
The size of your heart can vary depending on your
age, size, or the condition of your heart. A normal, healthy, adult heart most
often is the size of an average clenched adult fist. Some diseases of the heart
can cause it to become larger.
The Exterior of the Heart
Below is a picture of the outside of a normal,
healthy, human heart.
Heart Exterior
The illustration shows the front
surface of the heart, including the coronary arteries and major blood
vessels.
The heart is the muscle in the lower half of the
picture. The heart has four chambers. The right and left atria (AY-tree-uh) are
shown in purple. The right and left ventricles (VEN-trih-kuls) are shown in
red.
Connected to the heart are some of the main blood
vesselsarteries and veinsthat make up your blood circulatory
system.
The ventricle on the right side of your heart pumps
blood from the heart to your lungs. When you breathe air in, oxygen passes from
your lungs through blood vessels where its added to your blood. Carbon
dioxide, a waste product, is passed from your blood through blood vessels to
your lungs and is removed from your body when you breathe air out.
The atrium on the left side of your heart receives
oxygen-rich blood from the lungs. The pumping action of your left ventricle
sends this oxygen-rich blood through the aorta (a main artery) to the rest of
your body.
The Right Side of Your Heart
The superior and inferior vena cavae are in blue to
the left of the muscle as you look at the picture. These veins are the largest
veins in your body. They carry used (oxygen-poor) blood to the right atrium of
your heart. Used blood has had its oxygen removed and used by your
bodys organs and tissues. The superior vena cava carries used blood from
the upper parts of your body, including your head, chest, arms, and neck. The
inferior vena cava carries used blood from the lower parts of your body.
The used blood from the vena cavae flows into your
hearts right atrium and then on to the right ventricle. From the right
ventricle, the used blood is pumped through the pulmonary (PULL-mun-ary)
arteries (in blue in the center of picture) to your lungs. Here, through many
small, thin blood vessels called capillaries, your blood picks up oxygen needed
by all the areas of your body.
The oxygen-rich blood passes from your lungs back to
your heart through the pulmonary veins (in red to the left of the right atrium
in the picture).
The Left Side of Your Heart
Oxygen-rich blood from your lungs passes through the
pulmonary veins (in red to the right of the left atrium in the picture). It
enters the left atrium and is pumped into the left ventricle. From the left
ventricle, your blood is pumped to the rest of your body through the aorta.
Like all of your organs, your heart needs blood rich
with oxygen. This oxygen is supplied through the coronary arteries as its
pumped out of your hearts left ventricle. Your coronary arteries are
located on your hearts surface at the beginning of the aorta. Your
coronary arteries (shown in red in the drawing) carry oxygen-rich blood to all
parts of your heart.
The Interior of the Heart
Below is a picture of the inside of a normal,
healthy, human heart.
Heart Interior
The illustration shows a
cross-section of a healthy heart and its inside structures. The blue arrow
shows the direction in which low-oxygen blood flows from the body to the lungs.
The red arrow shows the direction in which oxygen-rich blood flows from the
lungs to the rest of the body.
The Septum
The right and left sides of your heart are divided
by an internal wall of tissue called the septum. The area of the septum that
divides the two upper chambers (atria) of your heart is called the atrial or
interatrial septum. The area of the septum that divides the two lower chambers
(ventricles) of your heart is called the ventricular or interventricular
septum.
Heart Chambers
The picture shows the inside of your heart and how
its divided into four chambers. The two upper chambers of your heart are
called atria. The atria receive and collect blood. The two lower chambers of
your heart are called ventricles. The ventricles pump blood out of your heart
into the circulatory system to other parts of your body.
Heart Valves
The picture shows your hearts four valves.
Shown counterclockwise in the picture, the valves include the aortic
(ay-OR-tik) valve, the tricuspid (tri-CUSS-pid) valve, the pulmonary valve, and
the mitral (MI-trul) valve.
Blood Flow
The arrows in the drawing show the direction that
blood flows through your heart. The light blue arrows show that blood enters
the right atrium of your heart from the superior and inferior vena cavae. From
the right atrium, blood is pumped into the right ventricle. From the right
ventricle, blood is pumped to your lungs through the pulmonary arteries.
The light red arrows show the oxygen-rich blood
coming in from your lungs through the pulmonary veins into your hearts
left atrium. From the left atrium, the blood is pumped into the left ventricle,
where its pumped to the rest of your body through the aorta.
For the heart to function properly, your blood flows
in only one direction. Your hearts valves make this possible. Both of
your hearts ventricles has an in (inlet) valve from the atria
and an out (outlet) valve leading to your arteries. Healthy valves
open and close in very exact coordination with the pumping action of your
hearts atria and ventricles. Each valve has a set of flaps called
leaflets or cusps, which seal or open the valves. This allows pumped blood to
pass through the chambers and into your arteries without backing up or flowing
backward. |