The nervous system

The nervous system revision

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The nervous system: Responses

The nervous system allows the body to respond to changes in the body (the stimuli)

The change is detected by receptor is our main organs. These are:

  • Eyes- Light receptors
  • Ears- Sound and orientation receptors
  • Nose and tongue- Chemical receptors
  • Skin- Tempreture and pressure receptors

This process involves neurons and controlled by the brain, unless it's a reflex action, where it is controlled by your body.

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Structure of a neuron

The main parts of a nueron are:

  • Dendrite
  • Mythelin Sheath
  • Dendron
  • Nucleus
  • Axon + axon ending
  • Cell body

Order of process:

1. Nuerones transmit information around the body

2. Impulses enter nuerone through dendrite ending

3. Impulses travel through dendron to the cell body

4. Impulse sent through cell body until it reaches the Synapse.

5. Mythelin sheath coats neuron, to insulate it, making it travel faster.

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Reflexs arc's

Reflex action prevent injury, and is controlled by our body, not the brain.

Order of process:

1. Receptor cells detect change in the enviorment

2.  Sensory neuron send impulse to relay neuron

3.  Relay neruon send impulse to the motor neuron

4. Motor neuron sends impulse to the effector

5. Effector produces a response

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Synapses

The synapse is a gap where 2 neurons meet.

Process order:

1. Signal is transmitted accross the gap by chemicals called neurotransmitters.

2. Neurotransmitters diffuse accross synapse and bind receptor molecules on the membrane of the next neuron.

3. Nueron sent to trigger impulse

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Revision questions

What is a neurotransmitter?

It is a chemical substance that diffuses accross a synapse.

How does a mythelin sheath affect a neuron?

It insulates it, so it travels faster.

What are the receptors for ears and skin?

Ears- sound and orientation receptors

Skin- Pressure and temperature receptors

What are the 2 types of effectors?

Muscles and glands (reflex's)

How would  gland produce a response?

Secreting a substance

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