Organisms response - Neurones

List the distinguishing factors about the nervous system.

- Transmission via neurones

- Rapid in effect and transmission

- Localised response

- Short lived response

- Communication via nervous impulses

Motor neurone

Transmit nervous impulses from a relay neurone to an effector e.g. a gland

Intermediate neurone

Also called relay neurones. Transmit impulses between different neurones

Sensory neurone

Transmit nervous impulses from a receptor to another neurone

Describe dendrites.

Form synapses with a connector neurone

Describe dendron.

Transmits the action potential towards the body

Describe axon.

Always transmits action potentials away from the cell body. It terminates in the synaptic knobs

Describe myelin sheath.

Speeds transmission of the action potential made by schwann cells. It insulates the impulse

Describe schwann cells.

Form myelin sheath

Describe nodes of ranvier.

Gap in the myelin sheath where the axon is exposed. Here ions can pass through the plasma membrane which speeds the passage of impulses along the axon

In which direction along a neurone does the electrical impulse move?

Away from the cell body, towards the synaptic knobs

How do schwann cells exist around the axon?

They are wrapped around the axon like a tube of cling film

Diagram of schwann cell and axon.