Transcript THE CIRCULATORY SYSTEM

• The heart
• The blood vessels
• The blood
• Carries needed
materials to the cells
• Carries waste products
away from the cells
• Helps the body fight
diseases
• The heart is a hollow
muscular organ, about
the size of your fist,
that is located
between your two
lungs .
• The heart’s function is
to pump blood
throughout the body.
The Heart is actually two
separate pumps.
• The right side receives
blood from the body
and pumps it to the
lungs.
• The left side receives
blood from the lungs
and pumps it to the
body.
Each side of the heart is
composed of an upper and a
lower chamber.
• The atrium (upper
chamber) receives blood.
• The ventricles (lower
chamber) pump the blood.
• Valves located in the heart
keep the blood flowing in
one direction.
• The heart is protected
by the skeleton’s
sternum and rib cage.
• The heart is enclosed
by a protective tissue
called the pericardium.
• The human circulatory system is a
closed system, the blood is enclosed in
vessels.
• There are three types of blood vessels:
arteries, capillaries, and veins.
• Arteries carry blood away
from the heart.
• Because the force of the
blood leaving the heart is
very strong, the walls of the
artery are thick and
muscular.
• Pulse is the expanding and
relaxing of the artery walls
caused by the blood being
force out of the ventricles.
• The capillaries are the
smallest blood vessels.
• The capillaries are the sites
where materials are
exchanged with the cells.
• Because of this the walls of
the capillaries are very
thin.
• Veins carry blood back
to the heart.
• Because the blood is
now moving more
slowly, the veins have
valves inside to
prevent the blood from
going backwards.
Blood leaving the heart
enters the arteries. It is
then carried to the
capillaries, where
materials are dropped off
or picked up. Next it travels to the veins for its return trip
to the heart. In-between leaving the heart and returning,
the blood is carried to various cells and organs of the
body by the blood vessels.
Blood Pressure
• Pressure is the force something exerts over
a given area.
• Blood exerts a pressure, called blood
pressure, on the walls of the blood vessels.
• Blood pressure is caused by the force with
which the ventricles contract.
• The farther away from the contracting
ventricle the blood moves, the lower the
pressure it exerts, therefore veins have the
lowest pressure.
Blood is made up of four parts or
components:
• Plasma
• Red Blood Cells
• White Blood Cells
• Platelets
• Plasma is the liquid part of
the blood.
• It makes up about 55% of
your blood.
• 90% of the plasma is water,
the other 10% is dissolved
materials.
• Dissolved nutrients,
hormones, carbon dioxide,
and waste are carried by
the plasma
Plasma
Blood
Cells
• Red Blood cells take up and
deliver oxygen to the cells.
• They are made mostly of
hemoglobin, an iron rich
protein that chemically binds
with the oxygen.
• Red blood cells do not have
a nucleus, therefore, they
only live about 120 days.
• Your bone marrow produces
new red blood cells.
• White blood cells are the
body’s disease fighters.
• They are also produced in
the bone marrow.
• They are larger than red
blood cells and have a
nucleus, but there are
fewer of them in the
blood.
• Platelets are cell fragments
that are important in
clotting blood.
• Platelets gather at the site
of a wound and release
chemicals, eventually
forming fibrin, which traps
blood cells and forms a
clot.
• Without the circulatory system multicellular animals would not be able to
maintain life.
• It is necessary so that all the cells of
the body will receive the required
nutrients and oxygen and not die due to
the poisons in their waste.
Pictures were obtained from the
following sites:
• Classroom Clipart at
http://63.200.14.139/cgibin/kids/imageFolio.cgi?img=0&search=rea
ding&cat=all&bool=and
• Google Image Search at
http://www.google.com/imghp?hl=en