Natural Science Unit 2. Interaction and the body

Hello everybody!

Here you have the most important information you need to know for the second exam of Natural Science.You are going to do it very well, but you have to STUDY!!!

1. RECEIVING INFORMATION

Thanks to our nervous system, sense organs and locomotor system, interact with the environment.
Our sense organs detect information from the environment and our sensory neurons transmit this information to our brain.

 2. PROCESSING INFORMATION

The nervous system, made up of neurons, receives information from the five sense organs, then analyses and interprets this information. 

• The central nervous system

Is made up of two parts: the brain (cerebrum, cerebellum, brain stem) and the spinal cord.

• The peripheral nervous system

It is made up of nerves which carry messages to and from the central nervous system.

 3. GIVING A RESPONSE

Our brain sends signals to the muscles of the locomotor system , which is also called the musculoskeletal system.


It is made up of the skeleton, joints and muscles.

• SKELETON: 

Its function is to support and give shape to our body and to protect the internal organs.

The skeleton is made up of bones and cartilage.

There are different types of bones:

• Short and wide bones (ex. our vertebrae that provide us support and stability).
• Flat and thin bones (ex. our ribs that protect our internal organs).
• Long and strong bones (ex. those in our arms and legs that are used for movement).

Some of the most important bones are:

• JOINTS: 

Our bones are connected to the joints by a strong and elastic tissue called ligaments. 

There are three types of joints:

• Fixed joints: They don't move (ex. The ones that join the bones in our skull).
• Semi-flexible joints: They allow some movement (ex. The ones that join the vertebrae in our spine).
• Flexible joints: They allow a lot of movement (ex. Elbows, wrists, knees, ankles and the shoulder).

• MUSCLES:

The muscles give our body shape and respond to the nervous system by contracting and relaxing.

The tendons are the tissues that connect muscles to bones.


Muscles can be categorised as:

• Voluntary: If we can move them at will (ex. The muscles in our arms).
• Involuntary: When they move automatically (ex. The muscles in our heart).

Some of the most important muscles are: