the structure and functions of neurons

Question 1

what is a neuron?

Answer 1

• A neuron is a nerve cell which transfers information between the nervous systems
• By transmitting signals electrically and chemically, these provide the nervous system with its primary means of communication

Question 2

electric transmission - the firing of a neuron

Answer 2

• When a neuron is in a resting state the inside of the cell is negatively charged compared to the outside
• When a neuron is activated, the inside of the cell becomes positively charged for a split second causing an action potential to occur
  → This creates an electrical impulse that travels down the axon towards the end of the neuron

Question 3

sensory neuron

Answer 3

• carry messages from the PNS to the CNS by processing information from one of the 5 senses
• long dendrites and short axons

Question 4

relay neuron

Answer 4

• found between sensory input and motor output/response
• short dendrites and short axons

Question 5

motor neuron

Answer 5

• carry signals from the CNS to effectors, which helps organs, glands and muscles function
• short dendrites and long axons

Question 6

neurons share the same basic structure:

Answer 6

1. cell body = nucleus which contains genetic material
2. dendrites = branch like structures, carry nerve impulses from neighbouring neurons towards the cell body.
3. axon = carries the electrical impulse away from the cell body down the length of the neuron.
   - It is covered in a fatty layer of the myelin sheath that protects the axon
   - Gaps in the axon called nodes of Ranvier speed up the
   transmission of the impulse
4. terminal buttons = end of the axon communicate with the next neuron in the chain across a gap called the synapse.

Question 7

neurons

Answer 7

• Neurons carry signals electrically along their axon and chemically across a synapse
• A synapse is a gap between two neurons
• Neurons never touch so to communicate they send chemicals across the synapse and these are picked up by the other neuron
• In all neurons, the dendrite/receptor cells receives the signal and then it travels through the neuron to the presynaptic terminal