The heart is a pear-shaped muscle located in the chest cavity on the left side of the body beneath the ribs. It is divided into four chambers - two upper chambers called atria and two lower chambers called ventricles. The heart continuously pumps oxygen-rich blood throughout the body via a cycle of contraction and relaxation called the heartbeat or cardiac cycle, consisting of systole when the ventricles contract and blood is pumped out, and diastole when the ventricles relax and fill with blood from the atria. The heart works nonstop to supply all parts of the body with blood.

1. THE HEART
Kimberly Cai CN-3
Stephanie Syjueco CN-22

2. WHAT IS THE HEART?
The heart is the organ that
supplies blood and oxygen
to all parts of the body.
The heart is pear shaped
and about the size of a fist.

3. Theheart is an
involuntary muscle,
meaning that unlike the
leg or arm muscles, the
cardiac muscle is not
under voluntary control.

5. WHERE IS THE HEART LOCATED?
The heart is located
beneath the protective ribs
on the left side.
It is located in the chest
cavity
It is surrounded by a
covering called the
pericardium.

7. THE HEART
The heart is divided into
four chambers, called the
right and left atria and
the right and left
ventricles

8. DIFFERENT ANIMALS MAY HAVE DIFFERENT
CHAMBERED HEARTS OR NONE AT ALL.
FOLLOWING IS THE GENERAL ANATOMY OF
THE HUMAN HEART.

9. PARTS OF THE HEART

10. MAIN FUNCTIONS OF THE HEART
 The role of the heart is to pump oxygen-rich
blood to every living cell in the body. In order
to achieve its goal, it must continuously beat
for a person’s entire lifespan. Because of its
vital role, a non-beating heart always results in
death

11.  The heart beats almost like a clock, about 60 to
80 times per minute, CONTINUOUSLY, whether
you are asleep or awake. The heartbeat is
regulated by a small "battery" located in the
right atrium called the SINUS NODE. Electric
currents travel in the heart by means of minute
fiber's in the wall of the heart, much like
concealed wiring inside a room.

12. THE HEARTBEAT
The heartbeat is made up
of systole and diastole,
which are the two stages of
a heartbeat.

13. SYSTOLE
 Stage when the ventricles of heart are
contracting resulting in blood being pumped
out to the lungs and the rest of the body.
 Thick, muscular walls of both ventricles
contract.
 Pressure rises in both ventricles, causing the
bicuspid and tricuspid valves to close.
Therefore, blood is forced up the aorta and the
pulmonary artery.
 The atria relax during this time. The left atrium
receives blood from the pulmonary vein, and
the right atrium from the vena cava.

14. DIASTOLE
 Stage when the ventricles of the heart are
relaxed and not contracting. During this stage,
the atria are filled with blood and pump blood
into the ventricles.
 Thick, muscular walls of both ventricles relax.
 Pressure in both ventricles falls low enough for
bicuspid valves to open.
 The atria contract, and blood is forced into the
ventricles, expanding them.
 The blood pressure in the aorta is decreased,
therefore the semi-lunar valves close.

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