3. The Structure And Function Of Neurons AO1 Flashcards
How many nerve cells are there in the human nervous system?
100 billion nerve cells, 80% are located in the brain
What are nerve cells responsible for?
Transmitting signals electrically and chemically, they provide the nervous system with its primary means of communication
What are the three types of neuron?
- Motor neuron
- Sensory neuron
- Relay neuron
What is the role of a motor neuron?
Connect to the CNS to effectors such as muscles and glands
What dendrites/axons does a motor neuron have?
Short dendrites and long axons
What is the role of a sensory neuron?
Carries messages from the PNS to the CNS
What dendrites/axons does a sensory neuron have?
Long dendrites and short axons
What is the role of a relay neuron?
Connect sensory neuron to motor or other relay neurons
What dendrites/axons does a relay neuron have?
Short dendrites and short axons
What is the cell body (soma)?
Includes a nucleus which contains the genetic material of a cell
What is a dendrite?
Branch-like structures that protrude from the cell body, they carry nerve impulses from neighbouring neurons towards cell body
What is an axon?
Carries the electrical impulses away from the cell body down the length of the neuron
What are terminal buttons?
They’re at the end of the axon, communicate with the next neuron in the chain across a gap called the synapse
Explain a neuron in its resting state
When in its resting state, the inside of the cell is negatively charged compared to the outside
Explain a neuron when it’s activated
The inside of the cell becomes positively charged for a split second causing an action potential to occur
