science form 3

2. Blood circulatory system
The function of blood
circulatory systems are to:
i. Supply oxygen to all body.
ii. Eliminate carbon dioxide
iii.Transport waste product
like carbon dioxide and
urea for elimination.

3. Artery
Vein
a) Humans have a close blood
circulatory system.
b) Blood is carried to the heart
by vein blood vessel and
pump out from the heart
through artery blood vessel.

4. Artery
Vein
Artery – the blood
vessel that carries
blood out of the heart
Vein – the blood
vessel that carries
blood into the heart
Blood
capillaries
Blood capillaries-
Act as connectors
that joint the blood
vessel of arteries to
veins

6. CO2 blood
O2 blood
Go to body

7. The heart is a muscular organ
which contract and relaxes
without stopping to pump and
circulate blood to the whole
body.
he heart has four large chambers:
Left atrium
Right atrium
.Left ventricle
.Right ventricle

8. Left atrium and right atrium
are situated at the upper
part of the heart
Left ventricle and
right ventricle are situated
at the lower part of the heart.
The space in the atrium is smaller than in the ventricle.
The wall of ventricle is thicker and stronger than atrium

9. The wall of left ventricle
is thicker and more muscular
compared to right ventricle.
This is because stronger
pressure is needed by the
left ventricle to pump
the blood to our body.
The valve in the heart enable blood to flow in one
direction only. Blood is prevented from flowing back.

11. There are 3 types of valve in
the heart:
i. Tricuspid valve
ii. Bicuspid valve
iii.Semi lunar valve
The left chamber of the heart
contains oxygenated blood
The right chamber contains
deoxygenated blood.

14. TYPE OF VALVE POSITION FUNCTION
Tricuspid Between the right
atrium and right
ventricle
Prevents blood in the
right ventricle from
flowing back to the right
atrium
Bicuspid Between the left
atrium and the left
ventricle
Prevents blood in the left
ventricle from flowing
back to the left atrium
Semilunar At the base of the
pulmonary artery
and the aorta
Prevents blood leaving
the heart from flowing
back

16. TYPE OF BLOOD
VESSEL
FUNCTION
Pulmonary artery Carries deoxygenated blood from the heart
to the lungs
Pulmonary vein Carries oxygenated blood from the lungs to
the heart.
Aorta Carries oxygenated blood from the heart to
the whole body.
Vena cava Channels deoxygenated blood from all
parts of the body to the right atrium.
Four blood vessels are connected to the heart:

18. Right ventricle
S
Vena cava
Tricuspid
Valve
Right
atrium
Left ventricle
Bicuspid valve
Left atrium
Semilunar valve
Pulmonary
veins
Vena cava
Aorta
Pulmonary
artery

19. 1. The vena cava caries
deoxygenated blood from all the
body to the right atrium.
2. When it is filled with blood, the
wall of the right atrium will contract and push the blood
through the tricuspid valve into the right ventricle.
3. When the right ventricle is filled with blood, its wall will
contract and push the blood through the semilunar valve
into the pulmonary artery and go to the lungs.

20. 4. Gaseous exchange takes place
in the lungs. Carbon dioxide
diffused out and oxygen
diffused into the blood.
5. Oxygenated blood then flows from the lungs into the left
auricle through the pulmonary vein.
6. The left auricle wall contracts and pushes blood through
the bicuspid valve into the left ventricle.

21. 7. The contraction of the left ventricle wall pushes blood
through the semilunar valve into the aorta.
8. The aorta then carries the blood to the whole body.

22. The pathway of blood circulation:
Vena cava
Right auricle
Tricuspid valve
Right ventricle
Semilunar valve
Pulmonary artery
Semilunar valve
Left ventricle
Bicuspid valve
Left auricle
Pulmonary vein
Lungs
Aorta
Whole body

23. Video : Heart 1
Video: Heart 2

25. Blood vessels in humans
Blood vessels are tubes in the body that channel blood
3 types of
blood vessels
Artery
Vein
Blood capillary

26. Artery Vein Blood capillary
Structure
Function Carries blood
out of heart
Carries blood
into the heart
Carries blood
from artery to
vein
Type of
blood
carried
Oxygenated
blood (except
pulmonary
artery)
Deoxygenated
blood (except
pulmonary
vein)
Oxygenated
blood (artery)
Deoxygenated
blood (vein)
Rate of
blood flow
High pressure
blood flow
faster
Low pressure
blood flow
slowly
Blood flows very
slowly to enable
diffusion process

27. Artery Vein Blood capillary
Thickness
of blood
vessel
wall
Has thick,
muscular and
elastic.
Has thin less
muscular and
less elastic.
Has porous and
thin wall to
enable gas
exchange
Lumen
size
Small Big Very small
Existence
of valve
No Yes No

29. Oxygenated blood Deoxygenated bloodDifference
Present
Not present
High
Not present
Artery and
pulmonary vein
Oxygen
Carbon dioxide
Concentration
of digestion
food (glucose)
Waste product
(urea)
Blood vessel
that carries it
Not present
Present
Very low
Present
Vein and
pulmonary artery

30. Deoxygenated
blood
Vein
Artery
Blood capillary
Oxygenated
blood
Relationship between artery, vein and blood capillary
Cell

33. Vena cava and
veins
Arteries and
aorta

35. 1. Heart disease is caused by:
a. Damage to the valve
in the heart
b. Failure of the ventricle
and atrium muscular wall to
contract
c. Blockage of blood supply
to the heart as a result of
cholesterol deposits.

36. The importance of maintaining a healthy heart is to
a. Avoid contracting heart disease. If serious can
cause death
b. Ensure that our body cells get enough supply of oxygen

38. By :