Biopysch: Neurons & Synaptic Transmission

Question 1

What are the three types of neuron

Answer 1

Sensory: receive input from PNS & transmit to CNS. They have long dendrites and short axons

Relay: connect sensory to motor or other relay neurons. They have short dendrites and short axons

Motor: connect CNS to effectors such as muscles & glands. They have short dendrites and long axons

Question 2

Key parts of neurons

Answer 2

Cell body - contains main parts of the cell, e.g nucleus & mitochondria
Nucleus - contains genetic material
Dendrites - receive impulses from neighbouring neurons
Axon - carries impulses
Myelin sheath- insulates axon & speeds up transmission
Nodes of ranvier - gaps in myelin sheath that speeds up transmission
Terminal buttons - end of axon that communicates with neighbouring neurons

Question 3

What happens when a neuron is activated by a stimulus

Answer 3

The cell becomes positively charged, causing an action potential which travels the length of the axon

Question 4

What is synaptic transmission

Answer 4

This occurs chemically between the terminal buttons of one neuron to the dendrites of another

Question 5

The process of synaptic transmission

Answer 5

• action potential reaches terminal buttons
• neurotransmitters are released from synaptic vesicles & diffuses across the gap
• they bind with receptors on the post synaptic neuron
  Each receptor is specialised for a neurotransmitter, two broad categories
• the remaining neurotransmitter in the synapse is reabsorbed by presynaptic neuron
  Some drugs block the reuptake of neurotransmitters e.g SSRI