Neurons And Synaptic Transmission

Question 1

Sensory neuron

Answer 1

• They carry nerve impulses from sensory receptors to the CNS
• They have long dendrites and short axons

Question 2

Relay neurons

Answer 2

• They carry info across the spinal cord/brain from sensory neurons to motor neurons
• They have short dendrites and short axons

Question 3

Motor neurons

Answer 3

• They are responsible for either directly or indirectly controlling muscles.
• They carry impulses from CNS to effectors
• They have short dendrites and long axons

Question 4

Synaptic transmission

Answer 4

1) Information is passed down the axon of the neuron as an electrical impulse known as action potential.
2) At the end of the neuron, there are synaptic vesicles which contain neurotransmitters
3) When the electrical impulse reaches these vesicles , they release the neurotransmitter to diffuse across the synapse
4) These chemicals bind to receptors on the post-synaptic cell, which then become activated.
5) The neurotransmitter makes it either more or less likely that the post-synaptic neuron will ‘fire’
6) Neurotransmitters that don’t bind are either absorbed back into the pre-synaptic neuron in a process called reuptake, or are broken down by enzymes

Question 5

Reuptake

Answer 5

• Any neurotransmitter molecules that have not been absorbed by the receptors are reabsorbed
• They can then be used to replenish the vesicles for the next transmission

Question 6

Types of neurotransmitters (excitory and inhibitory)

Answer 6

Excitory neurotransmitters binding make a neuron more likely to ‘fire’, and the behaviour will occur

Inhibitory neurotransmitters binding make it less likely to ‘fire’, and make it less likely that a behaviour will occur