L2 Nervous system

Question 1

What are the two major compartments of the nervous system?

Answer 1

Central and peripheral nervous system

Question 2

What are the two sub-compartments of the peripheral nervous system?

Answer 2

Somatic nervous system (voluntary, movement of muscles)

Autonomic nervous system (involuntary, heartbeat, breathing)

Question 3

What’s a dermatome and a myotome?

Answer 3

1. Dermatome is one spinal nerve responsible for providing sensory to a region of skin (T4- Nipple, T6- Xiphoid process, T10-Umbilicus)
2. Myotome is one spinal nerve controlling a group of muscle (synchronized movement)

Question 4

What are the two different components of the autonomic nervous system?

Answer 4

Parasympathetic (rest digest)

Sympathetic (fight flight)

Question 5

How many spinal nerve segments do we have? What are the names and characteristics of each segment?

Answer 5

C1-C8

T1-T12

L1-L5

S1-S5

Coccygeal

Connus medullaris

Cauda equina

Question 6

What is the name of the final tip of the spinal cord and at what level is it situated?

Answer 6

Conus medullaris (L1-L2)

Question 7

What creates a top-bottom tension?

Answer 7

Filum terminale

Question 8

Where are the two spinal enlargements and where are they situated?

Answer 8

Brachial plexus (C5-T1)

Lumbosacral plexus (L1-S4)

Question 9

Where do the spinal nerves exit in regards to their corresponding vertebrae?

Answer 9

Above for C2-C8 (spinal nerve exits through the intervertebral foramen)

ex: C2 above CII, C8 above TI

Below for the rest (below cervical region)

ex: T2 below TII

Question 10

What are the different components of the neuron?

Answer 10

Dendrite - Cell body - Axon (myalin wrapped, accelerates transmission)

Question 11

What is the spinal cord composed of? (sagittal view)

Answer 11

White matter

Gray matter (posterior, anterior horns)

Posterior median sulcus

Anterior median fissure

Postero(antero)-lateral sulcus

Question 12

What are the different divisions of the spinal nerve?

Answer 12

• Dorsal/Ventral rootlets
• Dorsal/Ventral root
• Dorsal root ganglion (only post.)
• Spinal nerve (exits through intervertebral foramena)
• Dorsal/Ventral ramus

Question 13

What is the pathway of sensory and motor information in a reflex mechanism? (Not extrinsic back muscle)

Answer 13

1. Sensory region in skin
2. Ventral ramus
3. Spinal nerve
4. Spinal ganglion
5. Dorsal root/rootlets
6. Posterior horn
7. Anterior horn
8. Ventral rootlet/root
9. Ventral ramus
10. Muscle

IN THE DOOR OUT THE VENT

Question 14

Can dorsal rami receive motor information?

Answer 14

NO, dorsal and ventral rami can only receive the corresponding information (sensory, motor respectively)

The “intersection” is the spinal nerve

Dorsal rami can only send out motor information when it’s headed to the intrinsic back muscles

Question 15

Why does the spinal cord end at L1-L2?

Answer 15

At birth, the spinal cord is equal in length to the vertebral column but the vertebral column grows faster

The Cauda Equina fills up remaining space (horse hair)

Question 16

How are muscle fibers innervated?

Answer 16

Multiple muscle fibers are innervated by one nerve in order to contract simultaneously

Question 17

What are the meninges of the spinal cord?

Answer 17

1. Dura mater
   
   • Mater - Mother
   • Most superficial, toughest layer
2. Arachnoid mater
   
   • Arachnoid – Spider’s web (mesh)
3. Pia mater
   
   • Pia – Soft,protective
   • Surface of spinal cord
   • Portrudes laterally (denticulate ligaments)
     
     • Provides side to side tension

Question 18

What are the layers/spaces of the meninges?

Answer 18

1. Extradural space (epidural) - Fat
2. Subdural space
3. Subarachnoid space - Cerbrospinal fluid travels here

Question 19

To extract CSF, where would we insert the needle?

Answer 19

Access between L4/L5

• No spinal cord (cauda equina)
• Bigger gap between SPs
• Make the client bend over to open up the gap