The enviroment around us is constantly changing, for example light levels change depending if you are inside or outside and the time of day, the tempreture changes throughout the day, the weather changes and so on. On top of this you could have an accident. To deal with all of these events our nervous system has developed to respond quickly and effectively with changes in our enviroment.

The first step in your bodies is to detect that a change has happened. To do this we use receptors we have several different types of these:

  • Pressure Receptors - in our skin which detect touch
  • Heat Receptors - in our skin to detect tempreture changes around us and in our brain to monitor the core tempreture
  • Cold Receptors - in our skin to detect tempreture change around us
  • Pain Receptors - throughout our body to warn us of danger
  • Sound Receptors - in our ear monitoring vibrations and sending measages to the brain
  • Light Receptors - in our eyes monitoring light and colour changes and sending information to the brain
  • Smell Receptors - in our noses to sense different types of chemicals
  • Taste Receptors - on our tounge which detect different chemicals
  • Strech Receptors - to monitor movement in different parts of the body. 

Receptors are like any animal cells they have a nucleus, cytoplasam and cell membrane. 

Over time our bodies have evolved to place receptors in the body where they're needed most. For example we use our hands for a lot of everyday things like writting, eating ect. So over time we have developed more pressure receptors in the skin on our hands so our bain can get more information about what is happening and therefore have better control.

The Nervous System 

Once our receptors have detected a change our bodies need to respond to them, this is the role of the nervous system. It's made up out of two main parts:

1. The Central Nervous System (CNS) - this is made up of the brain and spinal cord (contains relay neurons) and it's job is to decide the responses that our bodies make. 

2. The preipheral (outside) nervous system - this is made out of sensory receptors and motor effectors which detect the change and then carry out the response which they are told by the CNS. 

In simple terms when our receptors detect a change, we go through a 4 step response: 

1. Meassage is sent by a sensory neurone to the brain/spinal cord.

2. A relay nuerone in the brain or spinal cord carries the meassage and connects it to the correct motor neurone. 

3. A motor neurone carries a meassage to the correct effector.

4. The effector carries out the response. 


To fully understand how…


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