Download The Heart

The Heart
human heart
The Heart
 The
heart is a cone-shaped, muscular organ
about the size of a fist.
 It
is located between the lungs directly
behind the sternum and is tilted so that the
apex (pointed end) is oriented to the left.
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Composition of the Heart
The
heart is mostly made up of
cardiac muscle tissue known as
myocardium.
The
heart lies within a thick,
membranous sac that secretes a
small amount of lubricating fluid.
This sac is called the pericardium.
The
inner surface of the heart is
lined with connective tissue and
endothelial tissue. This is known as
the endocardium.
Composition of the Heart
The
heart is mostly made up of
cardiac muscle tissue known as
myocardium.
The
heart lies within a thick,
membranous sac that secretes a
small amount of lubricating fluid.
This sac is called the pericardium.
The
inner surface of the heart is
lined with connective tissue and
endothelial tissue. This is known as
the endocardium.
Myocardium Muscle Tissue
Chambers of the Heart
The heart has four chambers:
 Two
upper, thin-walled chambers
are called atria (singular atrium).

The atria receive blood.

The right atrium receives blood
from the body via the superior
vena cava.

The left atrium receives blood
from the lungs via the pulmonary
veins.
Chambers of the Heart
Chambers of the Heart

Two lower, thick-walled chambers called ventricles.

Ventricles pump the blood.

The right ventricle pumps blood to the lungs via
the pulmonary arteries.

The left ventricle pumps blood to the body via the
aorta.
Chambers of the Heart
Valves of the Heart
 The
heart has four valves which direct the flow
of blood and prevent its backward movement.
 Two
valves are found between the atria and
ventricles and are called atrioventricular
valves (a.v).

The a.v. valve on the right side of the heart
is called the tricuspid valve because it has
three flaps or cusps.

The a.v. valve on the left is called the
bicuspid (mitral) valve – it has 2 flaps.
Valves of the Heart
 Two
valves are found between the ventricles
and their attached vessels. These are known
as the semi-lunar valves – their flaps resemble
half-moons.

The pulmonary semilunar valve is found
between the right ventricle and the
pulmonary arteries. Blood is pumped
through this valve on its way to the lungs.

The aortic semilunar valve is found between
the left ventricle and the aorta. Blood is
pumped through this valve on its way to the
body tissues.

The valves of the
heart are supported
by strong fibrous
strings called chordae
tendinae.
Major vessels
 There
are five major blood vessels that
lead into and out of the heart.
 The
superior vena cava carries oxygen
poor blood to the heart from the upper
portion of the body. Blood from this
vessel enters the right atrium.
 The
inferior vena cava carries oxygen
poor blood to the heart from the lower
portion of the body. Blood from this
vessel enters the right atrium.
Major Vessels
 The
pulmonary arteries carry blood
from the heart to the lungs. Blood
carried in this vessel exits the heart
from the right ventricle.
 The
pulmonary veins carry oxygen rich
blood from the lungs to the heart.
Blood from this vessel enters the left
atrium.
 The
aorta carries blood from the heart
to the body tissues. Blood carried in
this vessel exits the heart from the left
ventricle.
Passage of Blood through the
Heart
1.
Oxygen poor blood enters right atrium
via superior and inferior vena cava.
2.
Right atrium sends blood through the
tricuspid valve to the right ventricle.
3.
Right ventricle pumps blood though the
pulmonary semilunar valve into the
pulmonary arteries which go to the
lungs.
4.
Blood becomes oxygenated in the lungs
and then enters the left atrium via the
pulmonary veins.
Passage of Blood through the
Heart
5.
Left atrium sends blood through
the bicuspid valve to the left
ventricle.
6.
Left ventricle pumps blood through
the aortic semilunar valve into the
aorta.
7.
The aorta delivers oxygen rich
blood to the body.
Blood flow videos
 http://www.youtube.com/watch?v=H04d3rJCLCE
 http
://www.youtube.com/watch?v=SvAVu-7E2gA