Neurons and Synaptic Transmission

What are the two main divisions of the nervous system?

Central nervous system and peripheral nervous system

What are neurons?

Nerve cells that transmit electrical and chemical signals

What is the function of neurons?

To transmit signals around the nervous system

What does a sensory neuron carry?

Impulses from sensory receptors to the CNS

What does a relay neuron carry?

Impulses between neurons within the CNS

What does a motor neuron carry?

Impulses from the CNS to effectors

What is the cell body?

The part of a neuron containing the nucleus and genetic material

What are dendrites?

Branch like structures that receive impulses from other neurons

What is the function of dendrites?

To carry impulses towards the cell body

What is an axon?

A long fibre carrying impulses away from the cell body

What is the function of the axon?

To carry electrical impulses away from the cell body

What is the myelin sheath?

A fatty layer surrounding some axons

What is the function of the myelin sheath?

It insulates the axon and speeds up impulse transmission

What are nodes of Ranvier?

Gaps between sections of the myelin sheath

What is the function of nodes of Ranvier?

They allow impulses to jump between gaps along the axon

What are terminal buttons?

Structures at the end of an axon that communicate with the next neuron

What is an action potential?

An electrical impulse travelling along a neuron

How are signals transmitted within a neuron?

Electrically

How are signals transmitted between neurons?

Chemically

What is a synapse?

A junction between two neurons

What happens when an action potential reaches the axon terminal?

A neurotransmitter is released into the synaptic cleft

What is the synaptic cleft?

The small gap between two neurons

How does a neurotransmitter cross the synaptic cleft?

By diffusion

What happens when a neurotransmitter reaches the next neuron?

It binds to specific receptors

What can neurotransmitters have on the next neuron?

Excitatory or inhibitory effects

What is an excitatory neurotransmitter?

A neurotransmitter that increases the likelihood of an action potential

What is an inhibitory neurotransmitter?

A neurotransmitter that decreases the likelihood of an action potential

How can SSRIs affect serotonin?

They reduce the reuptake of serotonin

What is serotonin associated with?

Mood and social behaviour