Biopsychology - Reflex arc and Synaptic Transmission

Question 1

How is information passed down the axon of a neuron?

Answer 1

Information is passed down the axon of the neuron as an electrical impulse known as action potential.

Question 2

What is at the end of a neuron?

Answer 2

At the end of the neuron (in the axon terminal) are the synaptic vesicles, which contain chemical messengers, known as neurotransmitters.

Question 3

What happens when the action potential reaches the synaptic vesicles?

Answer 3

When the electrical impulse (action potential) reaches the synaptic vesicles, they release their contents of neurotransmitters. Neurotransmitters then carry the signal across the synaptic gap. They bind to receptor sites on the post-synaptic cell, thereby completing the process of synaptic transmission.

Question 4

Outline how a reflex arc works

Answer 4

• Sensory neuron detects stimulus.
• Electrical signal sent along dendrite, then along axon to axon terminal.
• Signal converts into chemical signal, which crosses synaptic cleft and is detected by relay neuron in spine.
• Reflex responses then passes immediately to motor neuron, which causes effector to pull away from stimulus e.g. hot pan.