CNS PNS ANS Q2

Question 1

What are the 3 main parts of the spinal nerves and where do the central and ventral roots merge?

Answer 1

Roots, Trunk, and Rami. The roots merge in the trunk.

Question 2

List and describe the meninges of the spinal cord.

Answer 2

Dura mater: this is the most outer region is very tough due to its fibrous network. Deep to it is the Arachnoid mater which is highly vascularized and will look like a spider web network. Deep to arachnoid is the Pia mater. It is the most delicate and will be intimate to the spinal cord.

Question 3

Where do the sympathetic nerves originate from?

Where do the parasympathetic cell bodies reside?

Answer 3

T1-L1 spinal nerves from the paravertebral ganglia.

In the brainstem and S2-S4 spinal nerves.

Question 4

What makes up the PNS? (describe the parts)

Answer 4

Autonomic nervous system which deals with the involuntary control and Somatic nervous system which deals with the voluntary control.

Question 5

Explain the difference between dermatome and myotome

Answer 5

Dermatomes are regions of the skin that correspond to a given spinal cord level. Myotomes are the muscles that correspond to a given spinal cord level.

Question 6

Where does the caudal extent of the spinal cord end?

Answer 6

L1 L2 area.

Question 7

The gray matter is made of 3 horns. What are they and which cell bodies are contained in each?

Answer 7

Ventral: Somatic
Lateral: Visceral. Exit out the ventral roots
Dorsal: Somatic and visceral. Referred to as secondary cell bodies. Exit out the dorsal roots.

Question 8

Where do the spinal nerves emerge from?

There is exception to this, what is it?

Answer 8

They emerge directly below their corresponding vertebra. The exception to this is with the cervical region, they emerge above. IE C1 spinal nerve would be above C1 vertebra while T1 spinal nerve emerges above T1 vertebra. Remember that there are 8 cervical spinal nerves even though there are only 7 vertebrae.

Question 9

There are 4 places where post ganglionic neurons are located, where are they?

Answer 9

Dorsal root ganglion, Paravertebral ganglia, Preaortic ganglia, and intramural ganglia.

Question 10

What are the two parts of the autonomic nervous system?

Answer 10

Sympathetic (fight or flight and Parasympathetic (rest and digest)

Question 11

What do the paravertebral ganglia serve?

Answer 11

Sympathetic neurons

Question 12

Where is the subarachnoid space and what is it filled with?

What are the dentate ligaments?

Answer 12

It is the open area where the arachnoid mater is found. It is filled with CSF.

They anchor the spinal cords to the walls of dura mater

Question 13

Review the dermatomes for the following spinal cord levels. C2, C4, C5, C6, C7, C8, T1, T4, T7, T10, L1.

Answer 13

C2- Occipital protuberance
C4- Collar
C5- Lateral shoulder
C6-Thumb
C7-Middle finger
C8-Little finger
T1-Medial elbow
T4-Nipple
T7-Xiphoid
T10-Umbilicus
L1-Inguinal

Question 14

Explain the functions of the white and grey ramus communicans

Answer 14

The white rami are preganglionic sympathetics between the spinal cord and the chain. The grey rami are pre and post ganglionic sympathetics traveling to the periphery. Note that in the T1-L2 you will see both grey and white, while above or below you will only see grey.

Question 15

What is the function of the splenic nerve?

Answer 15

The preganglionic sympathetics traveling from the sympathetic chain to the preaortic ganglia.

Question 16

The sympathetic nervous system will control the smooth muscles of which blood vessels and for what reason?

The parasympathetic nervous system will control the blood vessels of which organs and glands?

Answer 16

Sympathetic- Blood vessels to the organs to decrease blood flow for other parts of the body.

Parasympathetic- Visceral organs IE to cause the muscle contractions of digestion.

Question 17

What is the primary function of the ventral, lateral, and dorsal horns of the spinal grey matter?

Answer 17

Ventral is motor, Lateral is sympathetic nervous, and dorsal is sensory.

Question 18

How many vertebrae are there in the cervical, thoracic and lumbar regions?

Answer 18

Cervical-7 Thoracic-12 Lumbar-5

Question 19

As the body continues to develop from a fetus, what happens to the nerves located in the lumbar region?

Answer 19

Because the nerves do not grow as fast as the vertebral column, the nerves are drawn caudally.

Question 20

Which matter sends information to the brain and which sends the information away?

Answer 20

White matter sends information to the brain and grey is away.

Question 21

What is the dorsal root ganglion?

Answer 21

Location of the cell bodies in the dorsal root.

Question 22

What do the preaortic ganglia serve?

Answer 22

Visceral sympathetic neurons.

Question 23

Which matter contains the myelination, white or grey?

Answer 23

White matter

Question 24

Why does the spinal cord increase in size as you ascend towards the brain?

Answer 24

As you move closer to the brain you will have more nerves converging.

Question 25

What do the neural crest cells form from the embryo?

Answer 25

Peripheral nerve ganglia

Question 26

What are the myotomes for the spinal nerves C5, C6, and C7?

Answer 26

C5- Shoulder abduction
C6- Elbow flexion, wrist extension
C7-Elbow extension

Question 27

What is the afferent and efferent pathways?

Answer 27

Afferent is carrying signals from the periphery to the central nervous system and efferent is carrying signals from the CNS to the periphery.

Question 28

Which roots contain the afferent pathway and which contain the efferent pathway?

Answer 28

Dorsal
Afferent
Ventral
Eefferent

Question 29

What do the parasympathetic ganglia serve?

Answer 29

Parasympathetic neurons.

Question 30

What is an explanation as to why there is not as much grey mater located in the thoracic vertebrae?

Answer 30

There is not a whole lot of motor action being performed in the trunk.

Question 31

What makes up the CNS?

Answer 31

Spinal cord and brain

Question 32

In regards to the spinal cord, what is the gray matter and white matter composed of?

Answer 32

Gray matter is the cell bodies, or where the nucleus of the nerve is located.

White matter consists of the axons sending the information back to the brain.

Question 33

What do the dorsal root ganglia serve?

Answer 33

Sensory for somatic and visceral