Chapter: 3 Movement in & out of Cells

Neurons

• The human nervous system is made of special cells called neurons.
• Figure 12.2 illustrates a particular type of neurone called a motor neurone.
• Neurones contain the same basic parts as any animal cell.
• Each has a nucleus , cytoplasm and a cell membrane .
• However, their structure is specially adapted to be able to carry electrical signals very quickly.
• To enable them to do this, they have long, this fibres of cytoplasm stretching out from the cell body.
• The longest fibre in a neurone is called an axon.
• Axons can be more than a metre long. The shorter fibres are called dendrites.
• The dendrites pick up electrical signals from other neurons lying nearby.
• These signals are called nerve impluses.
• The signals passes to the cell body, then along the axon, which might pass it to another neurone.

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