Nervous system review

Question 1

Describe the divisions of the nervous system

Answer 1

Central Nervous System (brain and spinal cord)

Peripheral Nervous System

• Somatic (voluntary)
• Autonomic (involuntary) - Parasympathetic (rest/digest) & Sympathetic (fight/flight)

Question 2

Describe the 5 features of a neuron

Answer 2

Soma - body

Dendrites - extensions for receiving information

Axon - extension for transmitting information

Axon hillock - junction between cell body and axon

Axon terminal/s - end of axon, for synaptic connection with other neurons

Question 3

Describe the 5 basic steps of a neuron synapse

Answer 3

1. action potential reaches axon terminal and depolarizes membrane
2. voltage-gated calcium channels open and calcium flows in to neuron
3. calcium influx triggers synaptic vesicles to release neurotransmitter
4. neurotransmitter crosses synaptic cleft and bind to receptors on post-synaptic neuron
5. can inhibit an inhibitory or excitatory response from post-synaptic neuron

Question 4

Describe the 5 basic steps of action potential generation

Answer 4

1. voltage-gated Na+ (sodium) channels open, and Na+ flows into axon
2. membrane is depolarized and an action potential is generated
3. voltage-gated Na+ channels close, and voltage-gated K+ (potassium) channels open. K+ leaves the axon.
4. membrane is repolarized
5. voltage-gated K+ (potassium) channels close and membrane repolarizes

Question 5

Which types of cells form the sheath of axons in the CNS and PNS?

Answer 5

PNS - Schwann cells

CNS - oligodendrocytes

Question 6

How many spinal nerves are there?

Answer 6

31 pairs of spinal nerves:

8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal