Flashcards in Neurons (structure and function) Deck (25):
What are the three types of neuron?
Motor neuron, sensory neuron and relay neuron.
Outline the function of sensory neurones.
Carry messages from the PNS -> CNS.
Outline the structure of sensory neurones.
Long dendrites, short axons.
Outline the function of relay neurones.
Connect sensory neurones to motor neurones.
Outline the structure of relay neurones.
Short dendrites, short axons.
Outline the function of motor neurons.
Connects the CNS to effectors eg muscles.
Outline the structure of motor neurons.
Short dendrites and long axons.
What are the basic features of a neuron?
- cell body
- terminal buttons
What is a cell body in a neurone.
Includes a nucleus which contains the genetic material of a cell.
What are dendrites in a neurone.
Branch like structures that protrude from the cell body. These carry nerve impulses from neighbouring neurons towards the cell body.
What is the axon in a neurone?
The axon carries the electrical impulse away from the cell body -> length of the neurone.
What are the two main features of an axon in a neurone?
Myelin sheath and nodes of Ranvier.
What is the importance of the myelin sheath?
It is a fatty layer which protects the axon.
What is the importance of nodes of Ranvier?
These gals in the axon speed up the transmission of the impulse.
What are terminal buttons in neurons?
These communicate with the next neuron in the chain across the synapse.
When a neuron is in a resting state, the inside of the cell is ___________ charged compared to the outside.
Outline how +ve and -ve charges cause an action potential to occur.
1. At resting state, the inside of the cell of a neuron is negatively charged.
2. When a neuron is activated, the inside of the cell becomes positively charged - causing an action potential to occur.
3. This creates an electrical impulse (which travels down the axon towards the end of the neuron).
How are signals within neurons transmitted?
How are signals between neurons transmitted?
Outline how synaptic transmission occurs.
1. The electrical impulse reaches the pre terminal, which triggers the release of neurotransmitters from synaptic vesicles.
2. Once it has crossed the synaptic cleft, it binds to receptor sites on the post neuron.
3. The chemical message is converted back -> electrical impulse.
What are neurotransmitters?
Chemicals that diffuse across the synapse to the next neurone in the chain.
They generally have an excitatory or inhibitory effect.
Give examples of neurotransmitters.
Outline excitatory neurotransmitters.
Increases the +ve charge of the post neurone, making it more likely the neuron will fire.
Outline inhibitory neurotransmitters.
Increases the -ve charge of the post neuron, making it less likely the neuron will fire.