Term 2 The Nervous Sytem Part 2

Question 1

Role of the axon

Answer 1

Carries the electrical impulses across

Question 2

Describe the Structure and function of a neuron

Answer 2

• contains myelin sheath which insulates the the neuron for impulses to travel quicker. Prevent the electrical impulses from leaving
• carries electrical impulses from one neuron to another neuron
• contains dendrites send impulses to the cell body
• the cell body contains the genetic information

Question 3

synapse

Answer 3

Junction between two neurones

Question 4

What occurs at the synapse

Answer 4

Neurotransmitters are released by vesicles from the pre synaptic membrane into the synaptic cleft to the post synaptic membrane. The receptors in the post synaptic membrane generates an action potential

High concentration of neurotransmitters are released from the pre synaptic membrane. Diffuses to low concentration in the post synaptic membrane

Question 5

Cholinergic synapse

Question 6

Describe the process of synaptic transmission

Answer 6

-Depolarisation of pre-synaptic membrane causes opening of voltage-gated Ca2+ channels
-Ca2+ diffuse into pre-synaptic neurone / knob
-Causing vesicles containing ACh to move and fuse with pre-synaptic membrane
○ Releasing ACh into the synaptic cleft (by exocytosis)
-ACh diffuses across synaptic cleft to bind to specific receptors on post-synaptic membrane
-Causing Na+ channels to open
-Na+ diffuse into post-synaptic knob causing depolarisation
-If threshold is met, an action potential is initiated

Question 7

Dopamine

Answer 7

• a transmitter
• released in the brain