Contents
Functions of the Cardiovascular
System
 The Heart
 Blood Vessels
 Blood

Functions of the
Cardiovascular System
OBJECTIVE: Describe the main functions of
the cardiovascular system
 The main functions of the cardiovascular
system include delivering materials to cells
and carrying wastes away. Also, blood
contains cells that fight disease.
Functions of the
Cardiovascular System
Delivering Materials
 The heart continuously pumps blood in the
blood vessels throughout the whole body.
 Many of the substances your body needs
dissolve into the blood
Removing Wastes
 The Cardiovascular System also transports
waste form cells.
Functions of the
Cardiovascular System
Fighting Disease
 Blood contains cells that attack microorganisms that cause disease.
 It contains substances that seal cuts,
preventing blood loss and the entry of
microorganism.
The Heart
The cardiovascular system contains a
network of blood vessels with two major
loops.
 The first loop from the heart to the lungs
releases carbon dioxide and picks up oxygen
by the blood, and then returns to the heart.
 The second loop delivers oxygen nutrients
and picks up wastes throughout the body.
 The loops cross paths at your heart.

The Heart
Structure of the Heart
 The heart has a right side and a left
side, separated by a thick wall.
 Each side has two chambers: the Atrium
(upper chamber) and the Ventricle
(lower chamber).
The Heart
OBJECTIVE: Trace the pathway of blood
through the heart.
 The atria receive blood entering the heart.
Blood flows from the atria to the ventricles,
which pump blood out of the heart.
The Heart
Your Heartbeat
 The heart has 2 main phases. Diastole
and Systole
 In Diastole, the heart relaxes and the
atria fills with blood.
 In Systole, the heart contracts and
pumps blood.
The Heart
The rate at which your heart muscles
contract is regulated by the pacemaker, a
small group of cells in the wall of the right
atrium.
 Your heart beats at approximately 70 to 80
times per minute. When you are active, your
heart speeds up depending on the body’s
need for more oxygen and nutrients and to
remove excess carbon dioxide.

Blood Vessels
Blood Vessels
 Your heart pumps blood through an
extensive network of blood vessels
OBJECTIVE: Identify three types of blood
vessels
 The three main types of blood vessels in
your body are arteries, capillaries, and
veins.
Blood Vessels
Arteries
 Arteries are blood vessels that carry blood away
from the heart.
 Most arteries carry oxygen-rich blood.
 The largest artery in the body is the aorta. Blood
leaves the left ventricle through the aorta, which
branches into many smaller arteries.
Blood Vessels
Veins
 Veins are large, thin-walled blood vessels that
carry blood to the heart.
 From the capillaries, blood flows into small
vessels that join together to form veins.
 Skeletal muscle contractions help to squeeze
blood back toward the heart. By then, the pumping
force of the heart has little effect.
 Valves inside the veins prevent blood from
flowing backward.
Blood Vessels
Capillaries
 Capillaries branch out from the smallest
arteries. They are the smallest blood vessels in
your body.
 Oxygen and dissolved nutrients diffuse as blood
flows through the capillary walls and into your
body’s cells. At the same time, wastes from
body cells (carbon dioxide), diffuse into the
blood.
 They are involved in regulating body
temperature.
Blood Vessels
Measuring Blood Pressure
 Blood Pressure is the force with which blood
pushes against the walls of your blood vessels.
 a sphygmomanometer is an instrument to
measure blood pressure.
The first reading represents the systolic pressure
– the pressure caused when the heart’s ventricles
contract. When the sound stops, the provider
records the second reading – diastolic pressure –
the pressure when the ventricles are relaxed.
Blood Vessels

Normal Blood Pressure: Blood pressure is
considered normal if it falls within the range of 90/60
to 119/79.
Low Blood Pressure: Blood pressure lower than
90/60. Causes of Blood pressure include
medications, dehydrations, and allergic reactions.
High Blood Pressure: A person whose blood
pressure is consistently 140/90 or greater. People
with high blood pressure are likely to develop
hypertension.
Blood
OBJECTIVE: Identify the four components of
blood.
 The four components of blood are plasma, red
blood cells, white blood cells, and platelets.
Plasma
 Plasma is the liquid component of the blood.
 It makes up about 55% of the blood.
 It is mostly water, with nutrients, hormones, and
salts dissolved in it.
 Plasma also carries waste products such as
urea to the kidneys for removal from the body.
Blood
White Blood Cells
 White blood cells help protect you against
disease and foreign substances.
 They are larger than red blood cells but are less
numerous.
 Some white blood cells make chemicals that
help your body resist diseases such as cancer.
 Others destroy invading microorganisms by
surrounding and consuming them.
Blood
Red Blood Cells
 Red blood cells are cells that carry oxygen from
the lungs to all the parts of your body.
 Contains hemoglobin which is an iron-containing
substance to which oxygen binds.
 The reaction between oxygen and the iron in
hemoglobin gives blood its bright red color.
 Once the oxygen is diffused to tissues, blood
becomes a dull red.
Blood
Platelets
 Are cell fragments that play an important role in
the blood clotting process.
 Platelets stick to the edges of the cut and
release proteins called clotting factors.
 Clotting factors and other plasma proteins form a
net of fibers across the cut trapping platelets and
blood cells until a plug forms to seal the cut.
 When the plug dries, it forms a scab.
Blood
Blood Types
 A person’s blood type is determined by the
proteins present on the surface of the red blood
cells (It can be A, B, AB, or O– depending on
which proteins are present.)
 A second blood type is determined by the
presence or absence or the Rh factor protein.
 If red blood cells have the Rh factor, it is said to
be Rh positive. If red blood cells lack the Rh
factor, your blood is Rh negative.
 About 85% of people are Rh positive
Blood
Transfusions
 After an injury, surgery or some illness, a person
may require blood transfusion.
 During a transfusion, blood form a donor is
transferred to the patient’s bloodstream.
 Donated blood is tested to identify the blood type. It
is also screened for the presence of some
microorganisms such as those that cause hepatitis
or AIDS
 If a patient is given the wrong blood type during a
transfusion, the blood will clump together in the
patients blood vessels. This is a life threatening
reaction.
Questions



What are the main functions of the
cardiovascular system?
What are the 2 main phases of the heart?
Name the blood types
Answer



Delivering materials to cells, carrying
wastes away, and fighting diseases.
Diastole and Systole
A, B, AB, and O