our systems

1. Unit 4 3º Primary Science. Teacher Merche 1
UNIT 4: OUR SYSTEMS
1. OUR SENSES AND NERVOUS SYSTEM
We have five senses:
1) The organ of touch is the skin. We use our skin to identify hot or cold, hard
or soft, smooth or rough.
2) The organ of taste is the tongue. We use our tongue to identify different
flavours.
3) The organs of sight are the eyes. We use our eyes to identify color, shape,
size…
4) The organ of smell is the nose. We use our noses to identity different smells.
5) The organs of hearing are the ears. We use our ears to identify loud, quiet…
2. NERVOUS SYSTEM
The nervous system is made up of the brain, the spinal cord and the nerves.
 The brain is inside the skull.
o It controls everything.
o It receives messages from nerves
o It gives instructions to the nerves.
 The nerves are connected to the brain by the spinal cord.
3. LOCOMOTOR SYSTEM.
We use our locomotor system to moves our body, eat and speak.
Our locomotor system is made up of bones, joints, muscles and tendons.
a) Muscles: they are elastic and flexible.
 Funtions:
 We can move some muscles (example, arms and legs)
 We can´t move some of them. They move automatically (example, the heart)

2. Unit 4 3º Primary Science. Teacher Merche
b) Bones: they are hard and rigid.
 Funtions:
 Bones make up the skeleton.
 They support the body.
 They protect the organs: heart, lungs and brain.
c) Joins: two o more bones meet.
 The hip and the knee are joins.
d) Tendons: Tendons attach muscles to the bones.
 When a muscle contracts it pull on the bone
 How to look after our locomotor system?
4. OUR CIRCULATORY SYSTEM
Our circulatory system is a transport system.
 It carries nutrients from the food and oxygen from the air.
 It´s made up of the heart, the blood and the blood vessels.
a) Blood: The blood is a red liquid that goes around the body.
 2 process:
 Blood travels in thin tubes called blood vessels.
WE SHOULD DO WE SHOULDN´T DO
Get enough sleep
Eat food with calcium
Warm up before doing sport.
Strech after doing sport.
Carry heavy things
Sit with bad posture
Pick up/collect nutrient and oxygen
Drop off carbón dioxide and waste products

3. Unit 4 3º Primary Science. Teacher Merche 3
b) Heart: The heart is a muscle.
 It is in the middle of the chest.
 It pumps/beats blood to every part of the body.
Example:
- If we run our heart beats faster
- If we have a rest our heart beats slower.
5. RESPIRATORY SYSTEM
The respiratory system consists of breathing in and out. The oxygen enters
and the carbon dioxide leaves.
 The respiratory system is made up of the nostrils, the windpipe, the bronchi
and the lungs.
a) Nose: The nose has two holes called nostrils.
b) Windpipe: is a tube that divides into two smaller tubes called bronchi.
c) Lungs: are two sacks that are protected by our ribs.
 Process:
1) The air enters our nose (the nose warms the air and the hairs clean it).
2) The air goes down the bronchi into the two lungs.
3) In the lungs, the oxygen passes from the air into the blood
4) The carbon dioxide passes from the blood into the air.
5) The carbon dioxide leaves our body when we breathe out.

4. Unit 4 3º Primary Science. Teacher Merche
6. REPRODUCTIVE SYSTEM.
The reproductive system allows us to have babies.
 Men and women have different reproductive systems.
 MALE REPRODUCTIVE: The sperm are kept in the testicles.
 FEMALE REPRODUCTIVE: The eggs are kept in the ovaries.
 Process:
1) A sperm fertilises an egg from the woman.
2) The fertilised egg goes to the uterus.
3) It changes into an embryo.
4) The embryo grows bigger and bigger.
5) Nine months later a baby is born.