Download Structure of the Human Heart

Cardiovascular system
Heart:
The heart is a muscular organ found in all animals with
circulatory system (including all vertebrates), that is
responsible for pumping blood throughout the blood
vessels by repeated, rhythmic contractions.
The vertebrate heart is composed of cardiac muscle,
contain involuntary striated muscle tissue found only in
this organ, and connective tissue. The average human
heart, beating at 72 beats per minute, will beat
approximately 2.5 billion times during an average 66 year
lifespan. It weighs approximately 250 to 300 grams in
females and 300 to 350 grams in males.
Structure of the Human Heart:
Heart is actually shaped more like an upside-down pear.
Heart is located almost in the center of the chest,
but slightly tilted to the left. There are four cavities, or
open spaces, inside the heart that fill with blood. Two of
these cavities are called atria. The other two are called
ventricles. The two atria form the curved top of the
heart. The ventricles in bottom of the heart to form base
(Tends to left side of chest). The left ventricle contracts
most forcefully, so you can feel your heart pumping on
the left side of your chest.
The left side of the heart contains one atrium and one
ventricle. The right side of the heart contains the others.
Heart contain (wall), called the septum, separates the right
and left sides of the heart. A valve connects each atrium to
the ventricle below it. The mitral valve connects the left
atrium with the left ventricle. The tricuspid valve connects
the right atrium with the right ventricle.
The top of the heart connects to a few large blood
vessels. The largest of these is the aorta, or main artery,
which carries nutrient-rich blood from the heart. Another
important vessel is the pulmonary artery which connects
the heart with the lungs as part of the pulmonary
circulation system. The two largest veins that carry blood
into the heart are the superior vena cava and the inferior
vena cava. The superior is located near the top of the
heart. The inferior is located beneath the superior.
The heart structure makes it an efficient, the heart
pumps blood , therefore, must be strong. The cardiac
muscle contracts it push blood into the vessels. Nerves
connected to the heart regulate the speed of muscle
contract. When you run, your heart pumps more quickly.
When you sleep, your heart pumps more slowly.
To monitor the heart, scientists can use x-ray or
scanning technology to get picture. To really explore the
heart, scientists have to perform surgery. Heart surgery is
very risky because the heart pumping action is so critical
for survival. If the heart stops pumping, the body cannot
survive. Before beginning heart surgery, doctors connect
the patient to machine that pumps the blood for the heart.
Human Heart