Transcript Circulationbody’s transport system Chapter 16 Section 1 Key Concepts     What are the functions of the cardiovascular system? What is the function and structure of the heart? What.

Circulationbody’s transport system
Chapter 16
Section 1
1
Key Concepts
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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?
Key terms
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Cardiovascular system
Heart
Atrium
Pacemaker
Ventricle
Valve
Artery
Capillary
Vein
Aorta
Coronary artery
Pulse
Diffusion
Blood pressure
The Cardiovascular System
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Like the roads that link all parts of the
country your body has a “highway”
network-the cardiovascular system.
The cardiovascular system carries needed
substances to cells and carries waste
products away from cells. In addition,
blood contains cells that fight disease.
Delivering Needed Materials
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Blood carries needed substances by the
body from one part to another
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Ex. Oxygen from your lungs to other body
cells
Ex. Glucose is transported to cells to produce
energy
Removing waste products
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Cardiovascular system picks up wastes
from cells
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Ex. Cells break down glucose, and produce
carbon dioxide as a waste product
Carbon dioxide passes from the cells into the
blood
Cardiovascular system then carries carbon
dioxide to the lungs where it is exhaled
Fighting Disease
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Transports cells that attack diseasecausing microorganisms
Blood cells will kill the microorganisms and
help you get well
Heart
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Without the heart could blood flow
anywhere?
Each time the heart beats, it pushes blood
through the blood vessels of the
cardiovascular system.
Size and Location
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You heart is about the size of your fist
It is located in the center of your chest
The heart lies behind the sternum and
inside the rib cage
It is made of cardiac muscle-Does the
cardiac muscle get tired?
Heart Structure
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Heart has a right and a left side
Right and left sides are separated by a wall of
tissue called the septum
Each side has an upper and lower chamber
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Upper chamber-atrium (plural – atria)
Lower chamber-ventricle
A pacemaker is located in the right atrium to send out
signals that make the heart muscle contract
Atrium
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Receives blood that comes into the heart
Ventricle
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Pumps blood out of the heart
Atria/Ventricle
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Atria and ventricles are separated by
valves
This valve is a flap of tissue that prevents
blood from flowing backward
Valves are also located between the
ventricles and the large blood vessels that
carry blood away from the heart
How the heart works
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Phase one-heart muscle relaxes and heart fills
with blood
Other phase-heart muscle contracts and pumps
blood forward
When the heart muscle relaxes blood flows into
the chambers
Atria contract squeezing blood out of the atria
through the valves and into the ventricles
Ventricles then contract
(2)
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Contraction closes the valves between the
atria and ventricles making the lub sound
and squeezing blood into large blood
vessels
As valves between ventricles and blood
vessels snap shut they make the dup
sound
Two Loops
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Body has three kinds of vessels
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Arteries-carry blood away from heart
Capillaries-substances are exchanged
between the blood and body cells
Veins-carry blood back to the heart
(2)
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Blood flow is like a figure eight with the
heart at the center of the two loops
Loop one-blood travels from the heart to
the lungs and back to the heart
Loop two-blood is pumped from the heart
throughout the body and then returns
again to the heart
(3)
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Right side of heart pumps to lungs
Left side to the rest of the body
Blood travels in one direction, and takes
less than a minute to travel through your
body
Loop one
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To the lungs and back
Blood that flows into the right atrium contains
little oxygen and a lot of carbon dioxide
This is oxygen POOR blood-it is DARK RED
Blood then flows from the right atrium into the
right ventricle
The ventricle pumps the oxygen poor blood into
the arteries that lead to the lungs
As blood flows through the lungs, large blood
vessels branch into smaller ones
Loop Two-to the body and back
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Second loop begins as the left atrium fills
with oxygen rich blood coming from the
lungs
Blood then moves into the left ventricle
from the left ventricle blood is pumped into
the aorta-the largest artery in the body
(2)
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After passing through branching arteries, blood
flows through tiny capillaries in different parts of
your body, such as your brain, liver and legs
These vessels are in close contact with body cells
Oxygen moves out of the blood and into the body
cells, at the same time, carbon dioxide passes
from the body cells into the blood
Blood which is low in oxygen then flows back to the
right atrium of the heart through veins, completing
the second lap
Arteries
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When blood leaves the heart it travels through
arteries
Right ventricle pumps blood into the arteries that go
to the lungs
Left ventricle pumps blood into the aorta
Smaller arteries branch off the aorta
First branches are called coronary arteries and
carry blood to the heart itself
Other branches carry blood to the brain, intestines
and other organs, each artery branches into
smaller and smaller arteries
Artery structure
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Walls of arteries are generally very thick they
consist of three cell layers
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Innermost layer-made up of epithelial cells and is
smooth
Smooth surface enables blood to flow freely
Middle layer-mostly muscle tissue
Outer wall-flexible connective tissue
They are both strong and flexible
Arteries are able to withstand the enormous pressure
of blood as it is pumped by the heart and to expand
and relax between heart beats
Pulse
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The alternating expansion and relaxation of the
artery wall
Every time the heart’s ventricles contract they
send a spurt of blood out through all the arteries
in your body
This spurt travels
It pushes the artery walls and makes them
expand, after the spurt passes they relax and
become narrower again
Heartbeats are then number of times an artery
pulses beneath your fingers
(2)
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Eventually blood flows through tiny capillaries that
are in close contact with the air that comes into the
lungs
Air in the lungs has more oxygen than the blood in
the capillaries, oxygen moves from the lungs into the
blood
Carbon dioxide moves in the opposite direction-from
the blood into the lungs
As the blood leaves the lungs it is now rich in oxygen
and poor in carbon dioxide
Blood is bright red and flows to the left side of the
hear and will be pumped through the second loop
Regulating Blood Flow
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The layer of muscle in an artery acts as a control
gate
When the muscle contracts the opening in the artery
becomes smaller
When the muscle relaxes the opening becomes
larger
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Ex. You eat, your stomach and intestines need a greater
blood supply for digestion. More blood flows through them
In contrast when running your stomach and intestines
need less blood than the muscles in your legs arteries
leading to the digestive organs become narrowerdecreasing blood flow
Capillaries
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Materials are exchanged between the blood and
the body’s cells
Capillary walls are only one cell thick, allowing
materials to pass easily through them. Oxygen
and glucose pass from the blood through the
capillary walls to the cells. Waste products travel
in the opposite direction-from cells through the
capillary walls into the blood
(2)
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Materials are exchanged between blood
and the body cells by diffusion
What is diffusion?
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Ex. Glucose is more highly concentrated in
the blood than it is in the body cells, therefore,
glucose diffuses from the blood into the body
cells.
Veins
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Like those of the arteries they have three layers,
with muscle in the middle layer
The walls of veins are generally much thinner
than those of arteries
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Many veins are located near skeletal muscles, the
contraction of the muscles helps push the blood along
Larger veins in your body have valves that prevent
blood from flowing backward
Breathing movements which exert a squeezing
pressure against veins in the chest, also force blood
toward the heart
Blood Pressure
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Blood pressure is caused by the force with
which the ventricles contact
As blood moves away from the heart,
blood pressure decreases
The farther away from the ventricle the
blood moves the lower its force
Blood flowing near the heart arteries
exerts the highest pressure
Measuring blood pressure
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Blood pressure can be measured with a
sphygmomanometer
Blood pressure is expressed in millimeters of
mercury
First number is a measure of the blood pressure
while the heart’s ventricles contract and pump
blood into the arteries
Second number measure the blood pressure
while the ventricles relax
1. What does the cardiovascular
system consist of?
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Heart
Blood vessels
Blood
cardiovascular system deliver
throughout the body?
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Oxygen
Glucose
3. How does the cardiovascular
system get rid of carbon dioxide
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Carbon dioxide is passed from cells into
the blood and then carried to the lungs
where it is exhaled
4. What are the four chambers of
the heart?
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Right atrium
Left atrium
Left ventricle
Right ventricle
5. Which chambers contain
oxygen rich blood?
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The left atrium and left ventricle
6. What are the two loops of
blood flow?
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heart to the lungs and back to the heart
Heart to the body and back to the heart
7. When blood is pumped to the
body cells is it oxygen rich?
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Yes, it has just come from the lungs where
it released carbon dioxide and picked up
oxygen
8. What color is oxygen poor
blood?
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Dark red
9. What are you feeling when you
take a pulse?
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A spurt of blood pushing the artery walls
and making them expand
10. Why are capillary walls so
thin?
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Materials must be able to pass easily
between them and body cells
11. What happens to the force of
blood as it moves away from the
heart?
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It decreases
12. Where does blood returning
from the body enter the heart?
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Right atrium