3.2. Neurons And Synaptic Transmission

Question 1

What do neurons have?

Answer 1

1. Cell body
2. Axon
3. Myelin Sheath
4. Dendrites

Question 2

What is the cell body?

Answer 2

Control centre

Question 3

What happens with the axon?

Answer 3

Nerve impulses travel along to form an electrical signal

Question 4

What does the myelin sheath do?

Answer 4

Speeds up the nerve transmission

Question 5

Which neuron is the myelin sheath NOT on?

Answer 5

Relay neuron

Question 6

What do dendrites do?

Answer 6

At one end, these receive signals from other neurons

Question 7

What is the purpose of a neuron?

Answer 7

Allows communication with the nervous system

Question 8

Sensory neurons

Answer 8

• Info to the brain
• Receives info from your senses and these travel to the CNS
• Long dendrite, short axon

Question 9

Motor neuron

Answer 9

• Info away from the brain
• Carries info from the CNS to the muscles
• Short dendrite, long axon

Question 10

Relay neuron

Answer 10

• Sensory and motor neurons cannot communicate through a relay neuron
• Lie only in the CNS
• Short dendrite and axon

Question 11

What is synaptic transmission?

Answer 11

• Involves impulses crossing a gap between an axon terminal and an adjacent neuron (dendrite) called a synaptic cleft
• Neurotransmitters are chemical messages released by the vesicles in the pre-synaptic neuron
• They travel/ diffuse across the synapse and lock onto receptors on the post-synaptic neuron (dendrite)
• Some neurons increase firing in the receiving neuron (excitation) and others decrease firing (inhibition)

Question 12

How does drug treatment work?

Answer 12

Works by either increasing or decreasing the transmission of neurons across a synapse

Question 13

Why does synaptic transmission only travel in one direction?

Answer 13

• Due to diffusion
• Travels from a high to low concentration (the axon terminal has lots of info to pass on, the receiving dendrite has no information, it needs to be passed on)