Transcript Section 12.1

Section 12.1 Your Cardiovascular System
Your Cardiovascular System
Objectives
Describe the main functions of the
cardiovascular system.
Trace the pathway of blood through the heart.
Identify three types of blood vessels and the
four components of blood.
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Section 12.1 Your Cardiovascular System
Myth Blood is blue in color when it is not carrying
oxygen.
Fact Blood is bright red when it is carrying oxygen and
dark red when it is not. Veins appear blue in some
people because of the way light reflects from their skin.
What other knowledge about the
cardiovascular system do you hope to gain from this
chapter?
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Section 12.1 Your Cardiovascular System
Functions of the Cardiovascular System
• Your cardiovascular system, or the circulatory
system, consists of your heart, blood vessels, and
blood.
• The main functions of the cardiovascular system
include
• delivering materials to cells
• carrying wastes away
• In addition, blood contains cells that fight disease.
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Section 12.1 Your Cardiovascular System
Delivering Materials
• Your heart continually pumps the blood in your blood
vessels throughout your body.
• Many substances that your body needs dissolve in
the blood.
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Section 12.1 Your Cardiovascular System
Removing Wastes
• Your cardiovascular system transports wastes from
your cells.
• Your blood picks up carbon dioxide and transports it
to the lungs, where it is exhaled.
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Section 12.1 Your Cardiovascular System
Fighting Disease
• Your blood contains cells that attack microorganisms
that cause disease.
• It also contains substances that seal cuts.
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Section 12.1 Your Cardiovascular System
The Heart
• Think of your cardiovascular system as a network of
blood vessels with two major loops.
• The first loop leads from your heart to your lungs.
• The second loop circles through to the rest of
your body.
• Each time the heart beats, strong cardiac muscles
push blood through the blood vessels.
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Section 12.1 Your Cardiovascular System
Structure of the Heart
• Each side of the heart has two chambers: an upper
chamber called an atrium (plural, atria) and a lower
chamber, or ventricle.
• The atria receive blood entering the heart.
• Blood flows from the atria to the ventricles, which
pump blood out of the heart.
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Section 12.1 Your Cardiovascular System
The Heart
1)
2)
3)
4)
Major vessel from
upper body to heart
1
5
Vessels from
lung to heart
2
Right Atrium
The right atrium
receives blood from 3
the body that is low
in oxygen and high
in carbon dioxide.
4
Right Ventricle
The right ventricle
pumps oxygen-poor
blood to the lungs.
6
5)
The aorta carries
blood from the left
ventricle to the body.
6)
Vessel from
heart to lungs
7)
Vessels from
lung to heart
8)
Left Atrium
Oxygen-rich blood
is carried from the
lungs to the left
atrium.
9)
Left Ventricle
The left ventricle
pumps oxygen-rich
blood from the heart.
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8
9
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Section 12.1 Your Cardiovascular System
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Section 12.1 Your Cardiovascular System
Your Heartbeat
• The action of the heart has two main phases.
• In the first phase, the heart relaxes and the atria
fill with blood.
• In the second phase, the heart contracts and
pumps blood.
• 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.
• Average heart rate varies from one person to the
next and from one situation to the next.
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Section 12.1 Your Cardiovascular System
Active Art: The Heart
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Section 12.1 Your Cardiovascular System
Blood Vessels
• Your heart pumps blood through an extensive
network of blood vessels.
• The three main types of blood vessels in your
body are
• arteries
• capillaries
• veins
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Section 12.1 Your Cardiovascular System
Blood Vessels
Artery
Artery
Cross Section
Layer of cells
Smooth muscle
Connective tissue
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Section 12.1 Your Cardiovascular System
Arteries
• Blood vessels that carry blood away from the heart
are called arteries.
• Most arteries carry oxygen-rich blood.
• The largest artery in the body is the
aorta (ay AWR tuh).
• Arteries have thick walls that are both strong and
flexible.
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Section 12.1 Your Cardiovascular System
Capillaries
• Branching from the smallest arteries are capillaries,
the smallest blood vessels in your body.
• As blood flows through the capillaries, oxygen and
dissolved nutrients diffuse through the capillary walls
and into your body’s cells.
• Capillaries are involved in temperature regulation.
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Section 12.1 Your Cardiovascular System
Veins
• From the capillaries, blood flows into small blood
vessels that join together to form veins.
• Veins are large, thin-walled blood vessels that carry
blood to the heart.
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Section 12.1 Your Cardiovascular System
Blood Vessels
Capillary
Vein
Capillary
Cross Section
Vein Cross Section
Layer of cells
Smooth muscle
Connective tissue
Single layer of cells
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Section 12.1 Your Cardiovascular System
Measuring Blood Pressure
• Blood pressure is the force with which blood
pushes against the walls of your blood vessels.
• Normal Blood Pressure A blood pressure reading
is considered normal if it falls within the range of
90/60 to 119/79.
• Low Blood Pressure Blood pressure lower than
90/60 is considered to be low blood pressure.
• High Blood Pressure A person whose blood
pressure is consistently 140/90 or greater has high
blood pressure, or hypertension.
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Section 12.1 Your Cardiovascular System
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Section 12.1 Your Cardiovascular System
Blood
• The average adult has about 4 to 6 quarts of blood
circulating through his or her blood vessels.
• The four components of blood are
• plasma
• red blood cells
• white blood cells
• platelets
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Section 12.1 Your Cardiovascular System
Plasma
• The liquid component of the blood is called plasma.
• This straw-colored liquid makes up about 55 percent
of the blood.
• Plasma is mostly water, with substances such as
nutrients, hormones, and salts dissolved in it.
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Section 12.1 Your Cardiovascular System
Red Blood Cells
• The cells that carry oxygen from the lungs to all the
parts of your body are red blood cells.
• Red blood cells contain hemoglobin, which is an
iron-containing substance to which oxygen binds.
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Section 12.1 Your Cardiovascular System
White Blood Cells
• White blood cells help protect you against diseases
and foreign substances.
• Some white blood cells make chemicals that help
your body resist diseases such as cancer.
• Others destroy invading microorganisms by
surrounding and consuming them.
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Section 12.1 Your Cardiovascular System
Platelets
• Platelets (PLAYT lits) are cell fragments that play an
important role in the blood clotting process.
• When you get a cut, platelets stick to the edges of
the cut and release proteins called clotting factors.
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Section 12.1 Your Cardiovascular System
Blood Types
• A person’s blood type is determined by the proteins
present on the surface of the red blood cells.
• Depending on which proteins are present, a person’s
blood type can be type A, B, AB, or O.
• A second blood type is determined by the presence
or absence of the Rh factor protein.
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Section 12.1 Your Cardiovascular System
Transfusions
• After an injury, surgery, or some illnesses, a person
may require a blood transfusion.
• During a transfusion, blood from a donor is
transferred to the patient’s bloodstream.
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Section 12.1 Your Cardiovascular System
Transfusions
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Section 12.1 Your Cardiovascular System
Vocabulary
atrium
ventricle
pacemaker
An upper chamber of the heart that receives
blood from the rest of the body.
A lower chamber of the heart that pumps blood
out of the heart.
A small group of cells in the wall of the right
atrium that controls the rate at which the heart
muscles contract.
artery
A thick-walled blood vessel that carries blood
away from the heart.
capillary
The smallest type of blood vessel in the body.
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Section 12.1 Your Cardiovascular System
Vocabulary
vein
blood pressure
hypertension
plasma
red blood cell
A large, thin-walled blood vessel that carries
blood to the heart.
The force with which blood pushes against the
walls of blood vessels.
Blood pressure that is consistently 140/90 or
greater.
A liquid that makes up about 55 percent of the
blood.
A hemoglobin-containing cell that carries oxygen
from the lungs to other parts of the body.
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Section 12.1 Your Cardiovascular System
Vocabulary
white blood cell
platelet
A cell that helps protect the body from diseases
and foreign substances.
A cell fragment that plays an important role in
the blood clotting process.
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Section 12.1 Your Cardiovascular System
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Section 12.1 Your Cardiovascular System
End of Section 12.1
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