Download 16-1Cardio

The Body’s
Transportation System
Our Cardiovascular
System
Its Parts
The
cardiovascular
system (or circulatory
system) consists of three
parts: 1.)the heart,
2.)blood vessels, and
3.)blood.
The 2 Main Functions of
the Cardiovascular system


A.) The cardiovascular system’s bloodstream
carries needed materials to cells.
For example, blood carries oxygen from the
lungs to your body cells. Remember the
nutrients from the digestive system are
absorbed into blood vessel-filled villi lining
the small intestine. These nutrients are then
carried in the blood throughout the body to
wherever they are needed.
The Cardiovasc. Systems
Functions (cont.)
B.) The cardiovascular system also picks
up waste products from cells and delivers
them to places where they can be
eliminated.
 For example, when cells use glucose for
energy they produce CO2 as a waste
product. This CO2 is then carried by the
blood to the lungs where it is eliminated as
you exhale.

Cardio syst. Functions (cont)
 The
cardiovascular system also
transports cells that attack diseasecausing organisms.
 These can help you from becoming
sick and if you do get sick,these
disease-fighting blood cells will kill the
disease-causing microorganisms to
help you get well.
The Heart
The heart is a hollow muscular organ
that's main job is to pump blood
throughout the body.
 Each time it beats it pushes blood. The
force it exerts pushing blood creates your
blood pressure.
 It is made of cardiac muscle which can
contract without getting tired.
 It may beat over 3 billion times over the
course of your lifespan!!!!

The Heart (cont…._)
Its Structure:
The heart has 4 chambers. It is divided
into two sides and each side has 2
chambers-an upper and lower.
 The upper chambers (each is called an
atrium), receive blood that comes into
the heart.


The two lower chambers (called
ventricles) pump blood out of the heart.
How the Heart Works

The action of the heart works in two
phases. In the 1st phase, heart muscle
relaxes and the atria fill with blood. In the
second phase, the atria contract, pushing
blood through the heart valves to fill the
ventricles. Then the ventricles contract
(which closes the valves between the atria
and ventricles) pumping blood out of the
heart and through large blood vessels.
A small group of cells called the
Pacemaker (located in the right atrium),
send out electrical signals that tell the
heart when to contract, regulating your
heart rate.
 For example, the pacemaker is
constantly getting messages about the
body’s oxygen needs. Exercise causes
you to use up oxygen so your body
sends messages to the pacemaker to
increase the heart rate so that
oxygenated blood reaches body cells
faster.

Blood Vessels and
Circulation




The body has three different kinds of blood
vessels.
1.) Arteries: which carry blood away from the
heart.
From the arteries, blood flows into tiny blood
vessels called 2.) Capillaries where substances
like nutrients, O2, and wastes are exchanged
between blood and body cells.
Then blood flows into larger vessels called
3.)
Veins, which carry blood back to the heart.
Blood Vessels and Circulation
(cont…)

In our bodies, blood flows in two loops. In
the 1st loop, the heart’s right atrium
pumps O2-poor blood into the right
ventricle which then pumps blood into an
artery taking blood to the capillaries that
fill the lungs (where it picks up O2 and
gets rid of CO2) then into veins that carry
oxygenated blood to the heart (into the left
atrium).
Blood Vessels and
Circulation (cont…)

In the 2nd loop, the left atrium pumps
oxygenated blood into the left ventricle
which then pumps it into the aorta (the
largest artery). From the aorta blood flows
into smaller branching arteries that take it
throughout the body to capillaries where it
delivers things the body needs (like
nutrients, O2) and picks up wastes. Then,
the blood returns through veins again to the
heart (ending up in the right atrium)
completing the 2nd loop.