9. HEART
• Most powerful organ in the circulatory
system.
• Cone-shaped organ.
• Weight about 300g.
• Location: in the thoracic cavity, between
the lungs.
• A muscular organ made up of cardiac
muscles connective tissues and blood
vessels.
10. • The heart pumps blood to the whole body.
• The human heart consists of four chambers:
a) right atrium
b) left atrium
c) right ventricle
d) left ventricle
• The heart is connected to four main blood vessels
i) vena cava
ii) pulmonary vein
iii) pulmonary artery
iv) aorta
• The valves separate the atria/ atrium from the
ventricles. To ensure that the blood flows only in
one direction.
11. • right side of the heart contains
deoxygenated blood
• left side of the heart contains oxygenated
blood (blood rich in oxygen).
12. • Function the parts in the heart:
Parts Function
Superior
vena cava
Blood from the upper portion of the
body flows into the heart.
Aorta Blood from the heart is pumped to
the whole body.
Pulmonary
vein
Blood from the lungs is pumped
into the heart
Right atrium Cavity where blood flow from vena
cava into the heart
Tricuspid
valve
Prevents backflow of blood into the
right atrium
13. Inferior vena
cava
Blood from the lower portions of the
body flows into the heart
Pulmonary
artery
Blood is pumped into the lungs from
the right ventricle.
Left atrium Cavity where blood flows from the
pulmonary vein into the heart
Bicuspid
valve
Prevent backflow of blood into the left
atrium
Aortic valve Prevent backflow of blood into the left
ventricle
Left ventricle Cavity where blood flow into from the
left atrium through the bicuspid valve
Right
ventricle
Cavity where blood flow into from the
right atrium through the tricuspid valve
14. • Function of the heart:
1. pumps blood to the whole body.
2. The right side of the heart contains
deoxygenated blood.
3. Left side of the heart contains oxygenated
blood.
4. When the heart contracts, it forces the blood
out of the heart into the arteries.
5. When it relaxes, it receives blood from the
veins.
16. 6. When the right atrium is filled with blood it
contracts. This pushes the blood into the right
ventricle through the tricuspid valve. This valve
prevents blood from flowing back into the right
atrium.
17. 7. The right ventricle contracts and pushed the
blood into the pulmonary artery.
8. The pulmonary artery then transports the blood
to the lungs.
9. The blood receives oxygen in the lungs.
Oxygenated blood is carried back to the left
atrium by the pulmonary vein.
10. The left atrium contracts and pushes the blood
into the left ventricle.
11. The left ventricle contracts and pushes the
blood into the aorta.
12. The aorta branches into the arteries. These
arteries transport oxygenated blood to all parts
of the body except the lungs.
18. Blood vessels and their functions
• When the heart pumps the blood flows around the
body in a system tubes called blood vessels.
• There are three types of blood vessels
1. Arteries / artery
-blood vessels which transport blood away from the
heart.
2. Veins/ vein
-blood vessels which transport blood towards the
heart.
3. Capillaries/ capillary
-consist of network of fine, microscopic blood vessels.
20. • In the arteries blood flows quickly and at
the high pressure:
1. When the heart contracts,blood is forced
at a high pressure into the arteries.
2. The thick,elastic walls prevent the
arteries from bursting.
3. All arteries except the pulmonary artery
transport oxygenated blood to body
tissues.
22. • Capillaries are found very close to the cells of
the body.They join to form bigger tubes called
veins.They connect the arteries to the veins.
• Blood flows slowly in the capillaries and at a
higher pressure compared to the flows of blood
in the veins.
• Capillaries transport oxygenated blood to the
body cells.They transport deoxygenated blood
from the cells.
• The thin walls of the capillaries allow the
exchange of substances between the blood and
body cells.
• Substances such as oxygen,carbon
dioxide,nutrients and excretory products are
exchange between the blood and body cells.
25. COMPARISON ARTERY VEIN CAPILLARY
Cross
section
Lumen Narrow Wide Very
narrow
Function Transport
blood from
the heart
Transport
blood into
the heart
Transport
blood from
artery to
vein
28. • The veins have thinner muscular walls compare
to the arteries.
• Veins have valves. These valves ensure that
blood flows in only one direction, that is towards
the heart.
• As the blood passes through the organ, it loses
much of it pressure. By the time the blood enters
the veins, the blood pressure is relatively low.
• This explain why veins have thinner walls
compare to the arteries.
29. Compare oxygenated blood and
deoxygenated blood
Characteristics Oxygenated
blood
Deoxygenated
blood
Content of
oxygen
Colour
Gas
Rich Poor
Bright red Dark red
Oxygen Carbon dioxide
30. Path of blood flow in circulatory system.
• Humans have a double circulatory system.
• This means blood passes through the heart
twice for one complete circulation in the body.
• The human circulatory system is divided into
two sections:
1. The pulmonary circulation
2. The systemic circulation
31.
32. Human circulatory system
The pulmonary circulation The systemic circulation
Arterial
• Oxygenated blood from the
heart to other part of the body
venous
• deoxygenated blood from the
heart to other part of the body
33.
34. Role of blood in transport
• Transport oxygen
-Oxygen is transported from the respiratory organ
(lung) to the body tissues.
-The red blood cells transport oxygen to the body
tissues where oxygen is used in cell respiration to
release energy.
• Transport carbon dioxide
-Carbon dioxide from respiring cells dissolves in the
blood plasma. It is released into the alveoli and is
excreted by the lungs.
35. • Transport digested food
-Digested food such as glucose and amino
acids diffuses into the capillaries and carried to
the body cells.
• Remove excretory products and waste
products
-Excretory products such as carbon
dioxide,urea,water are transported to specific
organ for removal.
36. • Transport hormones
-Hormones which are secreted by the
endocrine glands are transported to where
they are needed.
• Distributes heat
-Heat produced locally is distributed to the
whole body.
-This also helps maintain body temperature.
38. Importance of a healthy heart
Why it is
important to
maintain a
healthy
heart?????•An unhealthy heart may
causes various health
problems which may lead to
death.
39. Heart attack:
1.The heart will stop pumping blood.
2.Blood will not reach critical organ like the brain
and the heart itself.
3.If the heart muscles do not receives enough
blood within in a few minutes the cell in the area
will die. This is fatal.
4.If the brain does not receive oxygenated blood,
critical brain cells may die.This may cause coma
or brain damage.
5.Toxic waste will quickly build up when blood stop
flowing.
40. HEART ATTACKS
• Occur when the blood flow to a part of the
heart is blocked, usually by a blood clot.
• If this clot cuts off the blood flow
completely, the part of the heart muscle
supplied by that artery begins to die.
41. b) STROKE and TIA (“mini-stroke”)
• happen when a blood vessel that feeds
the brain gets clogged or bursts.
• Then that part of the brain can’t work and
neither can the part of the body it controls.
42. 1.List the importance to
maintain a healthy
heart.
2.List the risk factors that
can trigger the heart
attack.
3.List the ways to
maintain a healthy
heart.
44. Risk factors that can trigger the
heart attack
• smoking
• high blood pressure
• too much fat in your diet/ obesity
• diabetes
• age,male
• hereditary
• poor blood cholesterol level.
45. The ways to maintain a healthy
heart.
1. Avoid smoking
2. Reduce the intake of fatty foods.
3. Maintain a moderate body weight
4. Avoid drinking alcohol
5. Reduce mental and emotional stress.
46. Exercise 2.1
1. Name the four chambers of the human
heart and the blood vessel connected to
each chamber.
2. State the difference in function between
the vena cava and the pulmonary vein.
• the right atrium connected to the vena cava.
•The left atrium connected to the pulmonary vein
•The right ventricle connected to pulmonary artery
•The left ventricle connected to the aorta
The pulmonary vein transports oxygenated blood from the lungs to the
right atrium whereas the vena cava transport deoxygenated blood from
the body tissues to the right atrium.
47. 3. List four substances which are
transported by blood.
4. State four ways that can prevent heart
disease.
1. Digested food
2. Excretory products
3. Respiratory gases
4. Hormones
1. Avoid smoking
2. Reducing the intake of fatty food.
3. Maintaining a moderate body weight
4. Avoid drinking alcohol
48. 2.2 Human blood
• An adult human has about 5 litres of
blood which is about 9% of his body
weight.
• Blood is the main carrier of the body
transport system.
49. • Carries nutrient and oxygen to the body
cells.
• Transport carbon dioxide and waste
products away from the cells.
• Fight diseases
• Helps to maintain a constant body
temperature.
52. 1. Plasma
plasma
• a) It is light yellow in colour.
• b) 90% water and 10%
dissolved substances.
53. c) Dissolved substances in plasma
include
• mineral salts
• excretory products
• oxygen
• carbon dioxide.
• nutrients
54. d) Function
i) Medium for transport nutrient and oxygen
ii) Transport excretory products
iii) Transport other substances such as
enzymes, hormones and antibodies.
55. iv) Helps to maintain the body
temperature.
v) Fibrinogen is the plasma protein
responsible for the clotting blood.
56. 2. Red blood cells (erythrocytes)
• a) Colour: red
• b) Shape: biconcave
• c) No nucleus
• d) Contains haemoglobin (red pigment)
Red blood cells
57. • e) Function: Transport oxygen from the
lung to the body cells.
• f) Produced in the bone marrow.
• g) Have a lifespan of about 4 months.
• h) Old red blood cells not function
normally. These are destroyed in the
liver and spleen.
58. 3. White blood cells (leucocytes)
• a) Larger than a red blood cells.
• b) There are about 600 to 700 red blood
cells to one white blood cells.
• c) Has no definite shape.
• d) Has a nucleus,colourless,not contain
haemoglobin.
White blood cell
59. • e) Produced in the bone marrow, lymph
nodes and spleen.
• f) These cells have lifespan of about few
days.
• g) Old white blood cells are destroyed in
the liver and spleen.
60. h) Function:
1.Protect the body against diseases.
2.Digest bacteria
3.Produce antibodies
4.Produce antitoxins to neutralise poisonous
substances.
61. 4. Platelets
• a) Fragment of cell produced in
the bone marrow.
• b) A platelets does not have any
nucleus.
• c) Does not have a definite
shape.
62. • d) Platelets play an important role
in the clotting of blood.
• e) They prevent excessive
bleeding and initiate healing or
repairing of the injury.
63. Blood group and compatibility
• Human blood can be classified
into four main groups which are
O,A,B and AB.
• Every individual belongs to a
particular blood group.
64. • Blood transfusion is the transfer of
blood from a donor to a recipient.
• In blood transfusions, the recipient’s
blood must be compatible with the
donor’s.
• If they are incompatible, blood cells
will agglutinate. This may lead to
death.
65. • A person with blood type O is
known as a universal donor.
• This blood group is compatible
with all other blood groups.
• It does not cause agglutination of
the blood cells inside the blood
vessels.
66. • A person with AB blood group is
known as a universal recipient.
• He can receive blood from all the
blood group, however he can only
donate blood to people of blood group
AB.
67. Compatibility blood transfusions
between the four blood groups:
Blood group Can donate to Can receive from
A A, AB O, A
B B, AB O, B
AB AB O, A, B, AB
O O, A, B, AB O
68. The importance of blood donation
• Blood donation does not bring us
any ill effects nor does it endanger
our health.
• Our body produces and replaces
blood very quickly.
• Therefore we should adopt a
positive attitude towards blood
donation.
69. Blood is needed in the following
situation:
1.For major and minor surgeries
2.To replace blood lost due to accidents.
3.To make blood constituents like red blood
cells, plasma and platelets.
4.For children suffering from thalassaemia
(bleeding disorders).
70. 5. For mother who encounter complications
during childbirth.
6. For patient suffering from anaemia and
leukaemia.
7. For victims who suffer burns on their
body.
8. To help controls blood clots.
72. a) The donor is interviewed and
given medical counseling.
b) The donated blood is tested for
Hepatitis B, C and HIV.
73. • c) The blood sent to the
hospitals where they are
stored in blood bank at 4°C.
74. • 4. Before the blood is used for
transfusion, the bags are taken out
and left at room temperature for two
hours
75. 5. There are two types of blood in the
blood banks:
a) Fresh blood which can last for 24
hours.
b) Stored blood at 4°C which can last
for about 40 days
76. Exercise 2.2
1. What is meant by blood?
2. State three functions of blood.
Blood is a tissue which consist of cells
suspended in a liquid medium called plasma.
1. Transported digested food
2. Transported excretory product
3. Protects the body against diseases
77. 3. How do white blood cells react to an attack
by bacteria?
4. Complete the following table to show
compatible blood transfusions.
The white blood cells will digest the bacteria and
produce antitoxin to neutralise the toxins produced
by bacteria.
Blood group Can donate blood to blood
group
Can receive blood
from blood group
O
A
O, A, B, AB O
A, AB O, A
78. How the leaves at the top of a tall tree obtain
water necessary for photosynthesis???
80. Transport tissues in plant
• 1. The transport system in plant helps
transport substances to all part of the
plant.
• 2. The transport system in plant consists
of thin tubes called vascular bundles.
81. • 3. Vascular bundles found in the
roots, stems and leaves.
• 4. Vascular bundles are made up
of the phloem, xylem and
cambium.
82. • 5) Xylem and phloem are two
types of tissues that involve in
the transport system of plant.
83. a) Xylem
• i) transport water and dissolved minerals
from the roots to the stems and
leaves.
• ii) Long tubes.
• iii) Have a thick and strong walls which
support the plant.
85. • 5. There are two types of tissues
that are involved in the
transport system of plant.
• 6. These are xylem and phloem.
• 7. Both of xylem and phloem
tissues present in roots, stems
and leaves.
86. Tissues involved in the transport system of plant:
Xylem
• transport water and dissolved
minerals from the roots to the
steams and leaves.
•Long tubes.
•Have a thick and strong walls
which support the plant.
•Xylem walls contain lignin. Water
cannot go through lignin because it
is not permeable to water. This
allow the xylem vessels to
transport water efficiently.
Phloem
• transport food from
the leaves to the
steams and roots
91. Transpiration
• 1. Transpiration is the process by
which a plant loses water in the form
of water vapour from leaves to the
environment.
• 2. The water vapour passes out of the
leaf through tiny pores called stomata
in the epidermis.
92. • 3. A stoma is a tiny pore surrounded
by a pair of cells known as a guard
cells.
• 4. The opening and closing of the
stomata are controlled by the guard
cells.
• 5. More stomata are found on the
lower side of the leaf compared to
the upper side.
93. An open stoma:
• the stomata of plants are
normally open during the day
to allow the exchange of
carbon dioxide and oxygen.
•Takes place during
photosynthesis.
•Loss of water by transpiration.
A closed stoma:
• occurs at night.
•Photosynthesis does
not take place.
•Slows down water
loss.
Guard cells
94. Factors that affect the rate of transpiration
• A potometer is used to measure the rate of
transpiration.
• The rate of transpiration depends on the:
Factors ` Rate of transpiration Reason
Humidity Increases with lower
humidity
On dry days,there is
less water vapour in the
air.
Temperature Increase with an increase
in temperature.
Rate of evaporation
increases.
Light intensity Increases with greater light
intensity
Evaporation of water
through the open
stomata increases.
Air movement Increases on windy days Moving air removes
water vapour from the
surface of the leaves.
95. The role of transpiration
1. Absorption and transport of water
2. Absorption and transport of mineral salts
from the soil.
3. Removal of excess water.
4. Cooling of plant
5. Exchange of gases
96. 1. Absorption and transport of water
• Enable water to be transported from the
root and steam to the leaves.
• This enables all cells in the plant to be
active and to remain in a state of
turgidity.
• This flow of water is continuous and is
called the transpirational stream.
97. 2. Absorption and transport of mineral salts
from the soil.
• Water in the soil contains dissolved
minerals salts.
• During transpiration,the minerals salts
present in the soil are absorbed by the
roots and transported up the stems and
to the leaves.
98. 3. Removal of excess water.
• Transpiration thus helps to get rid of the
excess water from the plant.
4. Cooling of plant
• Transpiration has a cooling effect on
plants.
• As the water from the transpiration
evaporates, heat from the plant is used
up.This cools the plant.
99. 5. Exchange of gases
• Carbon dioxide is needed for
photosynthesis.During transpiration,the
opening of stomata allows carbon
dioxide from athmosphere to diffuse
inside the leaf.
• Oxygen which is produced during
photosynthesis diffuses out into the
athmosphere through the stomata.
100. Exercise 2.3
1. Name the structure P and Q.State one
function of P and Q.
PQ
P is guard cells which controls the size of the stoma.
Q is stoma which allow water vapour from the leaf to
escape to the athmosphere during transpiration.
101. 2. What is the meaning of transpiration.
3. Give two reason why transpiration is important
to plant.
4. State four factors which affect the rate of
transpiration.
Transpiration is the process by which plant lose water in the
form of water vapour from its leaves to the environment
• helps the plant to absorb water containing dissolved
minerals.
• get rid of excess water from the plant.
1. Humidity
2. Temperature
3. Light intensity
4. Movement of air
