Week 1: Nervous System

Question 1

What is included in the CNS?

Answer 1

• Brain - divided into 3 major parts: hindbrain (lower part), midbrain, forebrain
• Spinal cord - a column of nerves between the brain and the peripheral nervous system
• Brainstem - connects the brain to the spinal cord

Question 2

What is included in the PNS?

Answer 2

Everything else e.g. spinal nerves, cranial nerves
- Connects CNS to rest of body
- Both motor and sensory

• Somatic: 12 pairs cranial nerves, 31 pairs spinal nerves
• Autonomic: Sympathetic, parasympathetic

Question 3

Describe the general function of the central and peripheral nervous systems:

Answer 3

Enables the body to react to changes in environment and controls body functions such as respiration and circulation

Question 4

What are the 2 divisions of the peripheral nervous system?

Answer 4

1. Afferent - sensory division
2. Efferent - motor division:
   - Somatic (voluntary)
   - Autonomic (involuntary); sympathetic and parasympathetic

Question 5

What are the functions of dendrites?

Answer 5

• Afferent signalling system
• Receive both excitatory and inhibitory axodendritic connection

Question 6

What is the function of the cell body (soma)?

Answer 6

Integrates information received by the dendrites

Question 7

What are the functions of axons?

Answer 7

• Efferent signalling system
• Starts at axion hillock (region free of nissl bodies)
• Single nerve fibre that extends to other parts of the body and conducts the action potential away from the cell body and dendrites toward the nerve terminals.
• Myelinated or non-myelinated

Question 7

What is the function of the axon hillock?

Answer 7

Generates action potential

Question 8

What are the 3 main connective tissue sheaths? From out to in

Answer 8

1. Epineurium - connected to surrounding tissue by mesoneurium
2. Perineurium
3. Endoneurium

Question 9

What are the 2 basic cell types of nerve tissue?

Answer 9

1. Neurons (nerve cells)
2. Glial cells (support cells)

Question 10

What parts of the neuron communicate to form a synapse?

Answer 10

The axon terminal of the transmitting (presynaptic) neuron and the receptive region of the receiving (postsynaptic) neuron

Question 11

What is the general function of myelin?

Answer 11

• Insulates axons; Increases speed of action potential propagation down the axon

Question 12

What are glial cells?

Answer 12

The several varieties of nonexcitable cells which support the neurons of the nervous system.
- These cells are generally smaller than neurons and outnumber them in the brain and spinal cord by 5 to 10 times

Question 13

Give examples of glial cells in the CNS and PNS

Answer 13

CNS:
Astrocytes - form a supporting framework for the nerve cells and nerve fibres
Oligodendrocytes - form myelin in the CNS
PNS:
Schwann cells - produce myelin