3. Introduction
The characteristics of living things are eight, abbreviated as MR NIGER D. in humans, Allah created
one or more systems to manage each of the characteristics, except death. This topic shall discuss
those systems as follows.
4. What is system?
System is a group of organs working together in a regular manner to carry out
simple or complex task. This include the skeletal system, circulatory system and
digestive system.
6. The skeletal system
This is a system of bones and cartilages, connected together in a way that form
the supporting framework (skeleton) of the body.
7. Types of skeleton
1. Endoskeleton – the internal skeleton
2. Exoskeleton – the external skeleton
8. Parts of the skeleton
1. Axial skeleton (main skeleton): this consist the skull, spine, ribs, and the
chest bone.
2. Appendicular skeleton (limb skeleton): this consist bones of the shoulder,
arms, hands, hip, legs, feet, fingers and toes.
9. CARTILAGE
This is a tough elastic tissue that covers end o bones. It prevent movable end of
bones from wear and tear.
LIGAMENT
It is a tight cord of tissue that hold bones together when fragment of bones are
found to be joined to form a large mass.
TENDON
It is a tough fibre-like tissue found at the end of muscle. It attaches to the bone
and also binds neighbouring bones together.
10. Types of joint
i. Ball and socket joint
ii. Hinge joints
iii. Sliding joints
iv. Pivot joints
11. Functions of the skeleton
i. Protects delicate organs
ii. Gives the body rigidity and support to soft parts
iii. Gives the body form and shape
iv. Provide points of attachment to muscles and connecting tissues that that
produce movement
v. Helps to store certain materials
13. The respiratory system
Respiration is the process by which the body uses atmospheric oxygen to gain
energy. Ordinarily, through the nose, we breath in oxygen and breath out carbon
(iv) oxide. But at the cell level, the oxygen is used to burn down food nutrients
(e.g. glucose from carbohydrate) to produce energy, carbon (iv) oxide and water
vapour.
glucose + oxygen → carbon (iv) oxide + water + energy
This process is called the internal respiration or tissue respiration.
14. Parts of the respiratory system
i. Nose
ii. Pharynx
iii. Larynx (voice box)
iv. Trachea (wind pipe)
v. Bronchi
vi. Lungs
vii. Bronchioles
viii. Aveoli (air sacs)
ix. Diaphragm
15. Functions of the respiratory system
i. Breathing: this is also called the external respiration, it is the exchange of air
between the lungs and the atmosphere
ii. Inspiration: this is the intake of air to the lungs, where oxygen diffuses into
the blood at the aveoli and carried to body cells by the red blood cells.
iii. Expiration: this is the out push of air from the lungs, when carbon (iv) oxide
diffuses out of the blood at the aveoli and moved into the lungs
16. Diseases of the respiratory system
1. Asthma: this is a condition when the lining of the trachea is swollen. It
disturbs the free flow of air and breathing out is usually accompanied by a
characteristic wheezing sound.
2. Emphysema: this is caused by the breakdown of the walls of aveoli. It
reduces the quantity of gas exchange in the lungs.
3. Bronchitis: this is a disease of that develop as a complication of the common
cold in children.
4. Pneumonia: this is when certain germ infect delicate tissue of the lungs
making breathing difficult and accompanied by pain in the chest.
