The document provides a comprehensive overview of the human circulatory system, detailing its structure, function, and interconnections with other organ systems. It explains the roles of the heart, blood vessels, and blood components, including red and white blood cells and platelets, and outlines the processes of pulmonary and systemic circulation. Additionally, it discusses how the circulatory system interacts with the digestive, excretory, nervous, endocrine, muscular, and skeletal systems to maintain homeostasis and overall health.

1. The Circulatory
System

2. Learning Targets:
• At the end of the lesson the students can
be able to:
- identify and described the structure
of the organs and issues composing the
cardiovascular system
- trace the flow of the blood in
cardiovascular system.

3. Can you
imagine what
can happen
when the
heart rests?

4. Function of Circulatory
System
• Circulates OXYGEN
and removes Carbon
Dioxide.
• Provides cells with
NUTRIENTS.

5. • Removes the waste
products
of metabolism to
the excretory organs for
disposal.
• Protects the body
against disease and
infection.
• Clotting stops bleeding

6. The Circulatory System is
divided into three major parts:
• The Heart
• The Blood Vessels
• The Blood

7. • One of the most amazing and
most complex organs in the
body.
• It is highly muscular organ and
is the size of our fist.
The Heart and Blood
Vessels

8. • It pumps blood
throughout the body by
way of involuntary
contractions of the
cardiac muscle.
• The heart is located in the
center of the thoracic or
chest cavity, slightly
toward the left.

10. • The right atrium
receives oxygen-poor
blood from the body
and pumps it to the
right ventricle.
• The right ventricle
pumps the oxygen-
poor blood to the
lungs.

11. • The left atrium
receives oxygen-rich
blood from the lungs
and pumps it to the left
ventricle.
• The left ventricle
pumps the oxygen-rich
blood to the body.

12. Four Valves of the Heart

13. • The four valves help maintain
the proper blood flow through
the heart.

14. • The tricuspid valve is between the
right atrium and right ventricle. They
often and close with precise timing to
make the heart pump blood effectively.

15. • The tricuspid and the bicuspid
valves are called atrioventricular
(AV) valves, meaning they are
located between the atrium and
ventricle.

16. • The bicuspid valve or
mitral valve is located
between the left atrium and
left ventricle.

17. • The pulmonary valve lies
between the right ventricle and
the pulmonary artery, which
takes blood to the lungs

18. • The aortic valve lies between the
left ventricle and the aorta.
• This valve (aortic valve) prevents
blood from entering the aorta
prematurely.

19. • The aortic valve
opens when the
ventricle contract,
allowing blood to
move from the heart
and start the journey
to the rest of the
body.

20. • The heart needs
passageway to distribute
blood throughout the body.
• These passageway are the:

21. • The arteries carries blood away
from the heart and generally
transport oxygen-rich
(oxygenated/carbon dioxide
poor) blood

22. • Capillaries connect arteries
and veins. This is where the
gas exchange between the
blood and the tissues takes
place

23. • Capillaries then merge into
venules then into larger
channels called veins .
• Veins - carry blood to the heart
and generally transport oxygen-
poor, carbon dioxide rich blood.

24. The Blood
• Avery vital red fluid (blood) that
flows through our blood vessels,
provide oxygen and nourishment
to our body cells This red fluid
(blood) also take away carbon
dioxide and waste product from
our body cells.

25. • It also helps maintain
body temperature and
controls pH.
• Blood is transported to
the different parts of our
body by the circulatory
system.

26. Blood is composed mainly
of:
• a) Plasma - the
yellowish liquid
that is composed
of 90% water that
carries nutrients,
hormones, and
other important
substances

27. b) Different blood cells:

28. The Red Blood Cells
(RBC)
• The red blood
cells, also
known as
erythrocytes ,
carry oxygen to
the cells.

29. • After transporting oxygen
to the cells, red blood cells
collect the waste gas
(carbon dioxide, the by-
product of cellular
respiration) and transport
it back to the lungs, where
carbon dioxide is expelled
from the body as we
exhale.

30. • The red blood
cells are the most
abundant of the
blood cells (around
5,000,000 red blood
cells in drop of
blood) and its
lifespan is 120 days.

31. • The red blood cells are red in
color because they contain
hemoglobin . Hemoglobin
contains iron (Fe) making it an
excellent transporter of
oxygen and carbon dioxide.

32. The White Blood Cells (WBC)
• The white blood
cells, also known as
leukocytes , battle
infection, attack and
destroy germs or
foreign proteins
that enter the body.

33. • There are about 7,000 WBCs per
milliliter of blood (mL) and this
number can be used as an
indicator of a disease.
• During infection, the body
produces more white blood cells
to help fight off the infection.

34. Several types of white
blood cells:

35. Several types of white blood
cells:
a) Neutrophil combats bacterial
and fungal infection
b) Eosinophil defends against
parasitic infections c) Lymphocytes
B-cells make antibodies to fight the
foreign protein and T-cells function
in immune response.

36. d) Monocytes remove dead
cells debris and clean up the
“crime scene” where the
body’s soldiers battle an
infection.
e) Basophil functions during
allergic and antigen (foreign
protein reactions.

37. Platelets
• Platelets, also known
as thrombocytes, help
the blood clot, thereby
preventing bleeding
when an artery or vein
is severed or broken.

38. • Blood clotting is a temporary
solution to stop bleeding.
• The lifespan of a platelet is from five
to nine days only. A normal platelet
count of a healthy individual is from
150,000 to 450,000 per milliliter of
blood

39. Plasma
• Blood plasma is the
pale, yellow fluid
where the blood cells
are suspended. Plasma
makes up more than
half of the total blood
volume, roughly 55%.

40. • Plasma also plays a
very important role in
osmosis, thereby
promoting the balance
of electrolytes
• Blood serum is blood
without the blood cells
and the clotting factors

41. Human Circulatory
Paths
• The circulatory system has two
distinct paths, the pulmonary
circuit and the systemic circuit.
• Although they are two distinct
path, they actually occur
simultaneously and not in a
sequential manner. Both side of
the heart work together.

42. Human Circulatory
Paths
• Pulmonary
circulation can be
summed up as the part of
the circulation that carries
oxygen-poor blood to the
lungs and bring back
oxygen-rich blood to the
heart.

43. • Blood enters the
pulmonary circuit
when the right atrium
receives oxygen-
poor (carbon dioxide-
rich) blood from body
tissues through the
superior vena cava
and the inferior vena

44. • As the blood leaves for the pulmonary
circuit, some of the blood move
through the systemic circuit.
• The superior vena cava receives
blood from the upper part of the
body, and the inferior vena cava
receives blood from the lower part
of the body.

45. • The blood passes through the tricuspid valve into
the right ventricle. From the right ventricle, the
deoxygenated blood is pumped out from the
heart through the pulmonary tract that splits into
the right and left pulmonary arteries going to the
lungs for oxygenation.

46. • Carbon dioxide in the blood diffuses into the
lungs to pick up fresh load of oxygen. At this
point, blood is now oxygen-rich (carbon
dioxide-poor). From the lungs, the blood
returns to the heart by way of the right and left
pulmonary veins.
• Pulmonary circulation end when oxygenated
blood returns to the heart

47. Systemic Circulation
• Systemic
circulation is the
movement of
oxygenated blood from
the heart for
distribution
throughout the body
and bringing in of
deoxygenated blood to
the heart.

48. • Oxygenated blood
enters the left
atrium, then the
blood passes
through the mitral
or bicuspid valve
and into the left
ventricle.

49. • With the great
pressure, the
oxygenated blood from
the left ventricle is
pumped into the aorta,
the biggest artery in
the body, to be
distributed throughout
the body via a network
of blood vessels.

50. • The aorta branches into
smaller arteries, then
into arterioles and
finally into capillaries.
Waste and carbon
dioxide diffuses out of
the cells and into the
blood, the oxygen
diffuses out of the
blood and into the cells.

51. • The blood is
now carbon
dioxide-rich
and oxygen-
poor.

52. • This deoxygenated
blood then continues
its travel and the
capillaries merge into
venules then to larger
veins and finally into
the superior and
inferior vena cavas
that drain into the
right atrium of the
heart.

53. STRUCTURE and FUNCTION:
Working Together of the
Different Organ Systems
• The circulatory system supplies food
nutrients and oxygen that all the
cells of a living body needs.
• In turn, it collects the metabolic
wastes that body cells produce.

54. • Such dual function of the
circulatory system requires a
systematic coordination with
other organ system.
• To carry out its vital functions, it
is imperative for the circulatory
system to reach out to all organs
of the body,

55. The Circulatory System and
Digestive System
• Most of the digested foods
are absorbed in the
intestinal villi .
• Intestinal villi is the tiny
fingerlike projections at the
lower portion of the small
intestine.
• Each villus is provided with
two kinds of vessels:
capillaries and lacteals.

56. • Molecules of simple sugars and amino acids
diffuse into the capillaries and reach the
blood.
• Molecules of fatty acids and glycerol diffuse
into the lacteals and reach the lymph. At
this point, the circulatory system takes over.
• The circulatory fluids, blood and lymph,
distribute the digested foods to all cells of
the body

57. The Circulatory System and
the Excretory System
• The circulatory system plays a very important
role in the excretion of metabolic waste products
for our body.
• The circulating blood is responsible for collecting
these waste products from all body cells and
transporting them to various excretory organs
through which particular wastes are expelled
from the body.
• How does the circulatory system work with the
kidneys , our body’s major excretory organs?

58. • The renal artery brings
blood with many impurities
to the kidney.
• In the kidney, the renal
artery subdivides into small
arterioles that branch into a
network of tiny capillaries
making up the glomerulus ,
which is enclosed by the
Bowman’s capsule.

59. • As blood passes through the
glomerulus, urine, water,
glucose, and salt are filtered
into the Bowman’s capsule.
However, when the blood
passes through the long
convoluted tubules of the
nephron, much of the water
absorbed through the
glomeruli is reabsorbed
together with the salts, blood
sugar, blood proteins and
other substances needed by
the body.

60. • The liquid which remains in the
tubules is now called urine.
• This excretory waste is passed on
from the kidney to the ureter and to
the urinary bladder for temporary
storage. As urine fills up the urinary
bladder, it becomes heavier and
heavier until the sphincter muscle that
closes the opening of the bladder
relaxes and the smooth muscles of the
bladder contracts, expelling the urine
through the urethra and out of the
body.

61. How does the circulatory
system work with other
excretory organs?
• The liver cells change
amino acids, through the
series of chemical reactions,
into urea.
• Urea, the nitrogenous waste
is then transported by the
blood from the liver mostly
to the kidney where it is
filtered out of the blood and
expelled as part of the
urine.

62. • The liver also
breaks down old
blood cells.
• Most of the iron
salts from the blood
cells are brought
back to the bone
marrow by the
blood.

63. • The rest of the broken
blood cells become part
of the bile which helps in
fat digestion.
• Urea is also transported
by the blood from the
liver to the sweat glands
of the skin where it is
expelled as part of sweat,
another excretory waste.

64. The Circulatory System
and the Nervous System
• The nervous system
works with the
circulatory system
mainly in the heart by
controlling the flow of
blood in the different
chambers of the heart.

65. • The nervous system
controls the “electrical
relay system” in the
heart by opening or
closing chambers of the
heart to ensure that
blood travels out of the
left ventricles into the
rest of the body.

66. • The muscle of the heart and that of the
blood vessels are called involuntary
muscle because they are not under the
control of our will.
• Their action are governed by the
autonomous nervous system through
the sympathetic and parasympathetic
nerves whose actions are opposite
each other.

67. • A sympathetic nerve makes the heart
beat faster while a parasympathetic
nerve slows down heart beat. Thus,
the sympathetic and the
parasympathetic nerves regulate and
control each other’s activity to
maintain homeostasis or the dynamic
balance in the functioning of the heart.

68. • The hypothalamus of the
forebrain in the central
nervous system plays
another important role for
homeostasis .
• Among its vital functions
are to regulate blood
pressure and to control
the secretions of many
hormones.

69. The Circulatory System and the
Endocrine System
• Certain glands in the body
release their secretions
directly into the bloodstream
instead of through tiny
tubelike duct.
•

70. • These tiny tube like duct are called
ductless or endocrine glands. Their
secretions are called hormones, are
special protein substances that are
present in small quantities in the
body.
• They bring about changes in cells or
tissues which are referred to as their
“targets”

71. • The effect of a hormone may
be an increased activity or a
decrease activity of the target
cells. It may also be just plain
maintenance of the cells.

72. Following are some examples of
hormone actions involving the
circulatory system
• 1.Adrenalin (adrenal gland hormone)
increases blood pressure and heart rate
and dilate blood vessels.
• 2. Insulin (a pancreatic hormone)
lowers blood sugar level.
• 3. Parathyroid hormones raises blood
calcium level.

73. The Circulatory System
and Some Other Organ
System
• The circulatory system depends
on the skeletal system for the
production of blood cells.
• The red blood cells are produced
in the red marrow of flat bones
(such as the ribs) and long bones
(such as thigh bones)

74. • Blood cells, including
red blood cells,
certain white blood
cells and blood
platelets are formed
from special
connective tissues
referred to as
hemocytoblasts.

75. • The circulatory system and the
muscular system keep each other
healthy.
• The healthier and more active the
muscular system is, the healthier the
circulatory system.
• Active muscles demand a greater
amount of oxygen and nutrients for
energy source and repair of worn-
out tissues.

76. • The heart pumps harder to
enable the blood to provide
these needs.
• Blood also collects waste
products from the
hardworking muscles and
carries them to their
respective excretory organs.

77. • If the circulatory system fails to
supply the necessary requirements,
the muscles will cramp and
eventually become dysfunctional.
• Long-term inactivity of the muscles
is detrimental to the overall health of
the cardiovascular system.

78. • The heart will weaken and lose mass while
the blood vessels serving the muscles will
atrophy or shrink along with the muscles
themselves.
• On the other hand, enough and regular
exercise increases the mass of body muscles
over time.
• The heart muscle strengthen and the size of
the blood vessels connected to the active
body muscles increases as well.