Neuroscience 1 - Introduction

Question 1

Define the central nervous system

Answer 1

The neurones that make up the brain and the spinal chord

Question 2

Define the peripheral nervous system

Answer 2

The neurones that go to the rest of the body, not in the brain or the spinal chord.

Question 3

What is the PNS functionally divided into?

Answer 3

• The somatic PNS (motor and sensory function of the body wall)
• The autonomic PNS (visceral/vegetative/involuntary - regulates the function of the viscera, such as smooth muscle, pupils and sweating)

Question 4

Define the term afferent in regard to the nervous system, and give examples.

Answer 4

• Neurones going to the the CNS

- Sensory

Question 5

Define the term efferent in regards to the nervous system and give examples.

Answer 5

• Efferent means going from the CNS to the periphery.

- Involves motor neurones

Question 6

Describe the gross brain anatomy.

Answer 6

• Frontal lobe at the front
• Parietal lobe in between the frontal and occipital lobe
• Occupital lobe at the back
• Temporal love at the bottom
• Cerebellum at the hindbrain

Question 7

What is the meninges?

Answer 7

The cover protecting the brain.

Question 8

Describe the structure of the spinal chord.

Answer 8

• Grey matter is made up of the cell bodies
• White matter is made up of the axons
• The dorsal root is sensory (afferent), while the ventral root is motor (efferent)

Question 9

Describe how axons pack into nerves.

Answer 9

• Spinal nerves contain efferent and afferent axons. They are bundled into fascicles surrounded by the perineurium.
• The nerve is surrounded by a epineurium capsule
• Individual axons may be myelinated or unmyelinated with endoneurium.

Question 10

What is the resting potential of a neurone?

Answer 10

-70mV

Question 11

What is the threshold potential for a neurone?

Answer 11

-55mV

Question 12

Describe regeneration in the PNS.

Answer 12

• Axons in the PNS can regenerate after injury
• Injury stimulates phagocytes which remove debris thy would inhibit regrowth
• This may be compromised by abnormal axon sprouting and non-specific target innervation (leads to neuropathic pain)

Question 13

Describe regeneration in the CNS.

Answer 13

• Glia exhibit inhibitory influence on regeneration
• Glial scars form in place of injured brain tissue
• Absence in guidance cues that stimulate axon growth

Question 14

What is the dorsal column-medial lemniscus pathway?

Answer 14

• This sensory pathway conveys touch, vibration and two point discrimination
• Stimulus travels up the spinal chord on the same side, then switches sides at the medulla.
• Continues to the primary somatosensory cortex

Question 15

Why is the spinothalamic pathway?

Answer 15

• Conveys temperature sensation and pain.

- Neurones change side at the spinal chord, then continue up to the primary somatosensory cortex.

Question 16

What is the lateral corticospinal tract pathway?

Answer 16

• Motor pathway from the precentral gurus to the medulla, where it changes side.
• Goes down the spinal chord on the same side.

Question 17

What is the vestibulospinal tract pathway?

Answer 17

• Used in balance

- The impulse travels down the same side of the body to flexor and extensor muscles so we don’t fall over.