5. Section 1: The Body’s Transport
System
What are the functions of the cardiovascular system?
What is the function and structure of the heart?
What path does blood take through the cardiovascular
system?
What are the functions and structures of arteries,
capillaries, and veins?
• 7.5.a Students know plants and animals have levels of
organization for structure and function, including, cells,
tissues, organs, organ systems, and whole organisms.
• 7.6.j Students know that contractions of the heart
generate blood pressure and that heart valves prevent
back flow of blood in the circulatory system.
6. The Cardiovascular System
• Cardiovascular system
= the body system that
consists of the heart,
blood vessels, and
blood
The cardiovascular
system carries needed
substances to cells and
carries waste products
away from cells. In
addition, blood contains
cells that fight disease.
AKA= circulatory system
7. Delivering Needed Materials
• Most substances that need to get from one
part of the body to another are carried by the
blood.
• Oxygen and glucose are carried by blood.
– From Lungs
– To cells
9. Fighting Disease
• Also transports cells that attack disease-
causing microorganisms.
• They detect and kill the microorganisms.
10. HOW DOES THE CARDIOVASCULAR
SYSTEM HELP FIGHT DISEASE?
Reading Checkpoint
11. The Heart
• Heart = a hollow, muscular organ that pumps
blood throughout the body
• Each time the hearts beats, it pushes blood
through the blood vessels of the cardiovascular
system.
• About the size of your fist
• Inside the rib cage, behind sternum
• Made of cardiac muscle
12. The Heart’s Structure
• The right side of the heart is completely
separated from the left side by a wall of
tissue called the septum.
• Atrium = each of the two upper chamber of
the heart that receives blood that comes
into the heart
• Pacemaker = a group of cells located in the
right atrium that sends out signals that
make the heart muscles contract and that
regulates heartbeat rate
• Ventricle = a lower chamber of the heart
that pumps blood out to the lungs and body
• Valve = a flap of tissue in the heart or a vein
that prevents blood from flowing backward
13.
14.
15. How the Heart Works
• Two main phases:
– In one phase, the heart muscle relaxes and the
heart fills with blood.
– In the other phase, the heart muscle contracts
and pumps blood forward.
• Heartbeat can be heard during the pumping
phase.
• When the heart muscles relax, blood flows
into the chambers.
16. The force of the left ventricle is more than the force of the right ventricle. Why?
17. WHAT IS THE ROLE OF THE
PACEMAKER?
Reading Checkpoint
18. A Two-Loop System
• Artery = a blood vessel
that carries blood
Away from the heart
• Capillary = a tiny blood
vessel where
substances are
exchanged between
the blood and body
cells
• Vein = a blood vessel
that carries blood back
to the heart
19. Pattern of Blood Flow
1. In the first loop, the blood travels
from the heart to lungs and then
back to the heart.
2. In the second loop, the blood is
pumped from the heart
throughout the body and then
returns again to the heart.
3. The heart is really two pumps,
one on the right and one on the
left.
4. Blood travels in only one
direction.
20. Loop One: To the Lungs and Back
1. After visiting the body, blood is low
in oxygen but has a lot of carbon
dioxide.
2. Oxygen-poor blood is dark red.
3. Capillaries in the lungs are in close
contact with the air that comes
into the lungs.
4. Oxygen moves from the lungs into
the blood and carbon dioxide
moves from the blood into the
lungs.
5. Oxygen-rich blood is bright red.
21. Loop Two: To the Body and Back
1. After visiting the lungs, blood is
high in oxygen and low in carbon
dioxide.
2. Oxygen-rich blood is bright red.
3. Aorta = the largest artery in the
body
4. Capillaries in the body are in
close contact with body cells.
5. Oxygen moves out of the blood
and into the cells. Carbon dioxide
moves out of the cells and in to
the blood.
22. Arteries
• When blood leaves the heart it travels through
arteries.
• Coronary artery = an artery that supplies blood
to the heart itself
23. Artery Structure
• The walls of the arteries are generally very
thick.
• In fact, artery walls consist of three cell layers.
– innermost layer – epithelial cells
– middle layer – muscle tissue
– outer wall – flexible connective tissue
24.
25. Pulse
• Pulse = the alternating expansion and relaxation of
an artery wall as blood travels though an artery.
With each beat of the heart, a wave of blood is
pushed from the heart into the circulation. These
waves can be felt as pulsations in arteries close to
the skin surface, such as those in the wrist and neck.
26. Regulating Blood Flow
• The layer of muscle in an artery acts as a
control gate, adjusting the amount of blood
sent to different organs.
28. Capillaries
• In the capillaries,
materials are exchanged
between the blood and
the body’s cell.
• Capillary walls are only
one cell thick.
• Diffusion = the process
by which molecules
move from an area of
high concentration to an
area of lower
concentration
30. Veins
• After blood moves
through capillaries, it
enters larger blood
vessels called veins
which carry blood back
to the heart.
• The walls of veins, like
those of arteries, have
three layers, with muscle
in the middle.
Less pushing force by
the time it gets there.
•near skeletal muscles
•valves in larger veins
•breathing
movements exert a
squeezing pressure
against veins in the
heart
31.
32. Calculating a Rate
A rate is the speed at which something happens. When you
calculate a rate, you compare the number of events with the
time period in which they occur. Here’s how to calculate the
pulse rate of a person whose heart beats 142 times in two
minutes.
1. Write the comparison as a fraction:
2. Divide the numerator and the denominator by 2:
The person’s pulse rate is 71 heartbeats per minute.
33. Calculating a Rate
Practice Problem
Calculate your pulse rate if your heart beats 170 times in 2.5
minutes.
68 beats per minute
34. Blood Pressure
• Pressure = the force exerted on a surface
divided by the total area over which the force
is exerted
35. What Causes Blood Pressure?
• Blood pressure = the blood pressure that is
exerted by the blood against the walls of
blood vessels
• Caused by the force with which ventricles
contract.
39. Review 3
• When blood is pumped to the body cells, is it
oxygen-rich?
• Hint: Where has it just come from?
40. Review 4
• Name one needed material and one waste
product transported by the cardiovascular
system.
41. Learning Target
What are the functions of the cardiovascular
system?
What is the function and structure of the
heart?
What path does blood take through the
cardiovascular system?
What are the functions and structures of
arteries, capillaries, and veins?
