Organisation of the Nervous System

Question 1

Where do efferent fibres of the ANS originate from?

Answer 1

Either from the intermediate zone (or lateral column) of the spinal cord or specific cranial nerves and sacral nuclei

Question 2

What is a plexus?

Answer 2

• A dense network of peripheral nerves e.g. brachial plexus in the upper limb

Question 3

At what point does the spinal cord begin and end?

Answer 3

• Begins as it exits at the foramen magnum at the base of the skull
• Ends at L1 a the Conus Medullaris - giving rise to the Cauda Equina

Question 4

How many pairs of spinal nerves are there?

Answer 4

30 or 31 (if coccygeal nerves included)

Question 5

What are the 3 distinct anatomical structures of the brainstem?

Answer 5

1. Medulla
2. Pons
3. Midbrain

Question 6

What is the embryonic term equivalent of the brainstem in adults?

Answer 6

• The mesencephalon

Question 7

The brainstem contains nuclei for 10 of the 12 cranial nerves. What are the 2 exceptions?

Answer 7

• Olfactory nerve nucleus
• Optic nerve nucleus

Question 8

What are the 2 main brain structures within the posterior fossa?

Answer 8

• Brainstem + cerebellum

Question 9

How is the cerebellum connected to the brainstem?

Answer 9

• By 3 cerebellar peduncles

Question 10

What is the cerebral cortex?

How are neurones layered in the cerebral cortex?

Answer 10

• The outer layer of the cerebral hemispheres
• Both vertically and horizontally