The circulatory system transports blood throughout the body via blood vessels. The heart pumps blood through two circuits - systemic circulation carries blood to the body and pulmonary circulation carries blood to and from the lungs. Blood flows from the heart through arteries, then narrows into smaller arterioles and capillaries where nutrients and gases are exchanged with body tissues before returning to the heart through veins. Maintaining healthy blood pressure can prevent circulatory diseases like heart attacks and strokes.

1. circulatory
system

3. functions
TRANSPORTATION
• In your circulatory system, blood carries food,
water, oxygen, and other materials to your body’s
cells and tissues.

4. • Blood carries away waste materials, such as carbon
dioxide, a waste product of cellular respiration.
• Blood also picks up wastes produced by all other
chemical reactions that take place in your cells.
functions
Elimination

5. organs
• The heart is a
muscle that
pushes blood
through the
circulatory
system.
• A human heart
beats an average
of 70 to 75 times
per minute.
The heart

6. organs
• Your heart has
four main
chambers—two
upper chambers
and two lower
chambers.
The heart

7. organs
• Blood enters the
upper two
chambers of the
heart, called the
atria (singular,
atrium).
The heart

8. organs
• Blood leaves the
heart through the
lower two
chambers of the
heart, called the
ventricles.
The heart

9. organs
• Blood travels through your blood
vessels and reaches every cell in
your body.
• There are three main types of
blood vessels, arteries, veins, and
capillaries.
Blood vessels

10. organs
Blood vessels

11. organs
Blood vessels

12. organs
Blood vessels
If you were to take all of your blood
vessels and lay them out, they
would cover a distance of...
97,000 kilometer
That’s more than 2
times around the
earth!
Are you
ready
for a
mind
boggling
fact
??

13. organs
Arteries
• A vessel that takes blood away
from the heart is an artery.

14. organs
Arteries
• Artery walls are thick and can stand up to the high
pressure of the flowing blood.

15. organs
Arteries
• Blood pressure in the arteries
is high because arteries are
near the pumping action of the
heart.

16. organs

17. organs
Arteries
• The aorta is the
largest artery.
• It carries a large
volume of blood.

18. organs
Arteries
• Arteries branch into smaller vessels called arterioles.

19. organs
Capillaries
• Arterioles branch into tiny capillaries.
• Capillaries are tiny blood vessels that deliver supplies
to individual cells and take away waste materials.

20. organs
Capillaries
• Capillaries are
the smallest
blood vessels
in the
circulatory
system.

21. organs
Capillaries
• Many capillary walls
are only one cell
thick.
• Thin walls make it
possible for
molecules of oxygen,
food, water, and
waste products to
move between blood
and body cells.

22. organs
Capillaries
• Capillaries join and form larger vessels called venules.
• Venules join and form veins.

23. organs
Veins
• A vessel that brings blood toward the heart is a vein.

24. organs
Veins
• The pressure in veins is lower than in arteries.
• This is because capillaries separate veins from the
pumping action of the heart.

25. • Because there is less
pressure in the veins,
there is a greater chance
that blood could flow
backward.
• Veins have one-way valves
that prevent blood from
moving backward and
keep it moving toward the
heart
organs
Veins

26. • Because there is less
pressure in the veins,
there is a greater chance
that blood could flow
backward.
• Veins have one-way valves
that prevent blood from
moving backward and
keep it moving toward the
heart
organs
Veins

27. organs
• The inferior vena cava
is the largest vein.
• It carries blood from
the lower half of your
body to your heart.
Veins

28. • The inferior vena cava
is the largest vein.
• It carries blood from
the lower half of your
body to your heart.
organs
Veins

29. types of circulation
Systemic Circulation
• Blood leaves your heart and travels to
your body.
• Systemic circulation is the network of
vessels that carry blood from the
heart to the body and from the body
back to the heart.

30. types of circulation
Coronary Circulation
• The heart is a thick organ made of many layers of
cells.
• Most heart cells do not come into contact with
the blood inside the heart.

31. types of circulation
Coronary Circulation
• A network of arteries and veins called coronary
circulation supplies blood to all the cells of the
heart.
• Coronary circulation provides
oxygen and nutrients to the
cells of the heart. It also
removes carbon dioxide from
the blood.

32. types of circulation
Coronary Circulation
• Some of these vessels are inside the heart, while
others are on the outside of the heart.

33. types of circulation
Pulmonary Circulation
• Blood moves back and forth
between the heart and the
lungs.
• The network of vessels that
carries blood to and from
the lungs is called pulmonary
circulation.

34. types of circulation
Pulmonary Circulation
• Pulmonary circulation
carries oxygen-poor blood,
or blood low in oxygen,
from the heart to the lungs.
• It also carries oxygen-rich
blood, or blood high in
oxygen, from the lungs back
to the heart.

35. types of circulation
Pulmonary Circulation
• Blood that enters the heart
from the lungs is then
pushed to the rest of the
body.

36. types of circulation
Steps of Pulmonary Circulation
1. Blood, high in CO2 and low in
O2 returns from the body and
travels to the heart.
It enters the right atrium
through the superior and
inferior vena cava.
1

37. types of circulation
Steps of Pulmonary Circulation
Why are the pulmonary arteries
special?
They are the only artery that
carries blood that is low in
oxygen.
1
2

38. types of circulation
Steps of Pulmonary Circulation
3. Oxygen rich blood, from the
lungs, enters the heart
through the pulmonary vein
and into the left atrium.
1
2 3

39. types of circulation
Steps of Pulmonary Circulation
What makes pulmonary veins
special?
They are the only vein that
carries oxygen rich blood.
1
2 3

40. types of circulation
Steps of Pulmonary Circulation
4. The left atrium contracts and
forces the blood into the left
ventricle. Once that
contracts, blood flows out of
the heart and into the aorta.
1
2 3
4

41. circulatory health
Blood Pressure
• When the ventricles of the heart contract, they
push blood into the arteries.
• The arteries bulge a little because blood presses
against their sides.
• This bulging of an artery is what you feel when
you check your pulse.This pressure is called blood
pressure.

42. circulatory health
Blood Pressure
• Systolic pressure - pressure caused when the
ventricles contract and blood is pushed out of the
heart
• Diastolic pressure - pressure that occurs when the
ventricles fill with blood just before they contract
again.

43. circulatory health
Blood Pressure
• Normal blood pressure is considered to be 120
mm Hg (millimeters of mercury) or less during the
contraction of the ventricles.
• It is 80 mm Hg or less after the contraction.
• Normal blood pressure is written as 120/80 mm
Hg.

44. circulatory health
Hypertension
• Blood pressure higher than 140/90 mm Hg is
called hypertension, or high blood pressure.
• Hypertension can weaken the artery walls and
make them less flexible.

45. circulatory health
Atherosclerosis
• Atherosclerosis (a thuh roh skluh ROH sus) is the
buildup of fatty material within the walls of
arteries.
• Fat deposits can keep blood from flowing well in
the arteries.
• The deposits can also break loose, flow to a
narrower artery, and block it.

46. circulatory health
Atherosclerosis

47. circulatory health
Atherosclerosis
• A blockage in the heart
can cause a heart attack.

48. circulatory health
• A blockage in a blood
vessel in the brain can
cause a stroke.
Atherosclerosis

50. circulatory health
Heart Attacks, Strokes, and Heart Failure
• A heart attack happens when part of the heart
muscle dies or is damaged.
• Heart attacks occur when not enough oxygen
reaches cells in the heart.
• Most heart attacks occur when a blood vessel in
the heart is blocked.

51. circulatory health
Heart Attacks, Strokes, and Heart Failure
• A stroke happens when part of the brain dies or is
damaged.
• Most strokes are caused when not enough oxygen
reaches cells in the brain.
• A stroke might occur if a blood clot blocks a
blood vessel in the brain.

52. circulatory health
Heart Attacks, Strokes, and Heart Failure
• Heart failure occurs when the heart is not
working as well as it should.
• It can happen because of a heart attack, a problem
with heart valves, or diseases that damage the
heart.

53. circulatory health

54. circulatory health
Prevention
• Most risk factors can be controlled by making
good life choices.
• You can eat a healthful diet, control your weight,
exercise, and not smoke.

55. circulatory health
Homeostasis
• Once oxygen enters your body, your respiratory
system interacts with your circulatory system.
• Your circulatory system transports oxygen to all
cells in your body.
• It also transports nutrients from your digestive
system and hormones from your endocrine system.
• Your nervous system regulates your heartbeat.