Nervous System - Brain and Spinal Cord

Question 1

how is the nervous system structurally divided?

Answer 1

CNS - Brain and Spinal Cord

Peripheral NS - Cranial and spinal nerves

a) Somatic NS
b) Visceral NS

Question 2

which is longer - spinal cord or spinal column?

Answer 2

spinal column

Question 3

draw and label a neuron

Answer 3

Question 4

• which part of neurons make up white matter?
• which part of neurons make up grey matter?

Answer 4

white matter: axons

Question 5

draw and label a spinal cord cross section

• which bit houses sensory nerves?

Answer 5

dorsal root houses sensory nerves (i think)

Question 6

what surrounds the CNS? (3)

Answer 6

dura mater, arachnoid mater and pia mater

(outer —> inner)

Question 7

how many spinal nerves are there?

Answer 7

31

Question 8

label the spinal cord and the fibres that enter and exit the spinal cord

Answer 8

(from left to right)

• spinal nerve
• dorsal root ganglion
• dorsal root (opposite: ventral root)
• dorsal / ventral rootlets
• (raised block): grey matter)
• white matter

Question 9

• the spinal cord is made up of what?

Answer 9

grey and white matter

Question 10

what is grey matter of the spinal cord made up of?

what is white matter of the spinal cord made up of?

what is the arrangement of white and grey matter within the spinal cord?

what is the arrangement of white and grey matter within the brain cord?

Answer 10

grey: neuronal cell bodies and unmyelinated axons

white: myelinated axons

spinal cord arrangement: white matter surrounds the centrally distributed grey matter

brain arrangement: white matter in deeper areas, with surrounding gret matter

Question 11

what are the 5 sections of the spinal column? - which vertebrae are for which?

Answer 11

1. cervical (neck): 7 vert C1-C7
2. thoracic (mid back) : 12 vert: T1-T12
3. Lumbar (lower back) : 5 vert: L1-L5
4. Sacrum: 5 fused vert
5. Coccyx: 4 fused vert

= 33 vertabrae

Question 12

what and where is the cauda equina?

what and where is the cervical enlargement?

what and where is the lumbar enlargement?

Answer 12

cauda equina: typically levels L1-L5

cervical enlargement: C4-T1 level. It represents the origin of the brachial plexus.

lumbar enlargement: Between T11 and L1 representing the origin of the lumbar and sacral plexi.

Question 13

what are dermatomes?

Answer 13

A dermatome is an area of skin that is supplied by a single spinal nerve and these nerves transmit sensations, such as pain, from the skin to the CNS. Dermatomes have a segmented distribution throughout the body. The exact dermatome pattern can vary from person to person and some overlap between neighbouring dermatomes may also occur.

Question 14

what is the name of the foramen through which spinal cord passes?

Answer 14

foramen magnum

Question 16

what is the name of the shock absobers between vertabrae?

Answer 16

intervertebral discs

Question 17

what are the main anatomical components of a typical vertabrae?

Answer 17

• vertebral body
• transverse process
• spinous process
• superior articular processes
• vertabral foramen

Question 18

which type of vertabrae is this?

Answer 18

lumbar vert

Question 19

which vertabrae is this?

Answer 19

sacrum

Question 20

which vertabrae is this?

Answer 20

thoracic (heart shaped body)

Question 21

which vertabrae is this?

Answer 21

cervical vert.

Question 22

how mamy spinal nerves are there?

how are the split?

Answer 22

There are 31 pairs of spinal nerves and are named according to their origin:

8 pairs cervical (C1-C8)

12 pairs thoracic (T1-T12)

5 pairs lumbar (L1-L5)

5 pairs sacral (S1-S5)

1 pair coccygeal (C0)

Question 24

where does the spinal cord extend from / to? / terminate at?

what happens to spinal cord after this?

Answer 24

• foramen magnum at base of the skull -> L1/L2 vertabrae.

- terminates at the: conus medullaris

• Below the L1 / L2 the spinal nerves are bunched as cauda equina (The collection of nerves at the end of the spinal cord is known as the cauda equina, due to its resemblance to a horse’s tail)

Question 25

what are the two large enlargements of the spinal cord? why exist?

Answer 25

cervical enlargement and lumbosacral enlargement

• provide innervation to the limbs

Question 26

what does the filum terminale do?

Answer 26

A thin thread called filum terminale extends from the tip of the conus medullaris all the way to the 1st coccygeal vertebra (Co1) and anchors the spinal cord in place.

Question 27

what are nerve plexis?

how many plexi groups branch off the spinal cord?

Answer 27

nerve plexi: (Spinal nerves contribute to the formation of plexi (singular: plexus)). A plexus is a network of nerves that intermingle and become redistributed so that the peripheral nerve leaving the plexus contains fibres from multiple spinal nerve roots. Each limb muscle receives motor innervation from multiple spinal nerve roots.

4 main plexus groups: cervical, brachial, lumbar and sacral regions of spinal cord

Question 28

• which plexi supply the upper and lower limbs?
• what is the arragement of nerves in the thoracic region?

Answer 28

upper limbs: brachial plexus

lower limbs: lumbosacral plexus

thoracic region: spinal nerves in thoracic region are arranged segmentelly and do not contribute to the plexi