major organ systems - y7

1. Major organ systems

2. • Living things are also called living organisms
• Most living things have bodies composed of organs
• Organ: a part of the body that performs a special task
to help the organism live.
• Organ system: a group of organs that work to carry
out a special task.

3. Skeleton and muscles
• There are 206 bones in the human skeleton
• Each arm and hand have 30 bones
• Each leg and foot together have 29 bones

7. Skeleton and protection
•The brain and spinal cord are
made from soft tissue.
•They could be easily damaged
without a hard covering.

8. • The bones of the skull are
fused together to make a
strong case around the brain.
• The backbone is made of 33
bones known at vertebrae.
Skeleton and protection

9. •The ribs and backbone form
a protective structure
around the lungs and heart
Skeleton and protection

10. Skeleton and support
• The bones of the skeleton allow the
organs to be spread out in the body
without squashing into each other.
• The muscles account 45% of the
body weight.
• They are made from soft tissue but
gain their support from the bones to
which they are attached .

11. Skeleton and movement
• The place where bones meet is called a joint
• Some joints, like in the skull, cannot move because they are fused
• Most joints move
• The elbow and knee are called hinge joints because the movement is like the
hinge on a door.

12. • The bones are held together by fibers called
ligaments
It stops the bones coming apart when they
move.
• Parts of the bones in the joint are covered with
cartilage
It stops them rub over each other.
It is hard and slippery that reduces friction and
allows the bones to move over each other
Skeleton and movement

13. • In some joints, where there is a lot of
movement
There is synovial membrane make a
liquid called synovial fluid.
• the fluid acts like oil, reducing friction
and wear
Skeleton and movement

14. H.W
Q1 p. 2
Q3 p. 4, 5
Q6 p. 8

15. C.W
Q2 p. 3
Q4 p. 6,7
Q5 p. 7
Q7 p. 9

16. • It is made from tissue that has the power to
move
• It can contract to become shorter,
• When the muscle gets shorter it exerts a pulling
force
• The muscle cannot lengthen or extend itself.
• It needs a pulling force to stretch it again.
• This force is provided by the other muscle when
it contracts

17. • The movement of the muscle in the opposite way is called antagonistic
muscle pair.
• There are two types of muscles
• Smooth muscles in the alimentary canal
• Cardiac muscle in the heart

18. • The heart is located near the center of the chest
• It is made of cardiac muscle
• The beating of the heart makes the blood circulate
around the body
• The heart and blood vessels make up the
circulatory system

20. If you put your hands below your ribs,
You will feel your hands moving in and out.
They are being pushed by a muscle called
diaphragm
This helps us to breathe.
If you place your hands on your ribs
You will feel the ribs moving
They also help you to breathe

21. • The air enters through the nose
• Passes down the back of the mouth
• Goes into the voice box and windpipe
• The bottom of the windpipe divides into two tubes called bronchi
• The bronchi carries the air into the lungs

22. • Oxygen passes through the walls of the lungs and into the blood
• Carbon dioxide passes from the blood through the walls of the
lungs and into the air.

24. The main part of the digestive system is a tube that runs
through the body is called alimentary canal

25. • It takes between 24 and 48 hours for the food to travel along the alimentary
canal.
• A meal of boiled rice only stays in the stomach for up to two hours
• Roast chicken may stay for up to seven hours

27. • It contains the brain, spinal cord and
nerves
• The brain is enclosed in the skull
• The spinal cord is enclosed in vertebrae
• Nerves connect the brain to the eyes,
ears, tongue, nose and skin
• Messages travel through the nervous system as tiny electrical signals.
• The sense organs send signals to the spinal cord and the brain
• If the brain decides that the body should move, it sends signals to the
muscles

29. The waste produced by the body gets collected in
the blood.
As the blood passes through the kidney.
A waste called urea is filtered
from the blood with some water.
Water and urea are called urine

30. Water and urea can also be released
from the skin to cool the body.
Carbon dioxide is removed into the air.

32. The sense organs
• Eyes – sight
• Ears – hearing
• Nose – smell
• Tongue – taste
• Skin – touch
They provide information about
the surrounding by sending
electrical signals to the brain

34. • It is made of glands which releases
hormones into the blood.
• Example : adrenal gland releases a
hormone called adrenaline.
• It is found just above the kidney.
• You can feel the adrenaline when you
act in front of a large audience or take
part in athletics.
• This makes your heart beat faster
and direct more blood to your
muscles.

35. • It also controls the way people grow and develop.
• Hormone insulin helps the body store sugar from the digested food or use the
sugar to get energy.
• It is secreted by pancreas which is located behind the stomach.
• A lack of this hormone leads to a disease called diabetes.

36. Organ systems of a human body
• Skeletal system
• Muscular system
• Circulatory system
• Respiratory system
• Digestive system
• Nervous system
• Excretory system
• Sensory system
• Endocrine system