*ANS Review*

Question 1

In which spinal segments are IMLs found?

Answer 1

T1-L2,3 (p.58) – i.e. Thoracolumbar division.

Question 2

Where are the cell bodies of postsynaptic sympathetic neurons?

Answer 2

Either paravertebral or prevertebral ganglia.

Question 3

Define the function:

1. ) Axon

2. ) Dendrite

Answer 3

1. ) Axon: Carries impulses AWAY from the body.

2. ) Dendrite: Carries impulses TO the cell body.

Question 4

What type of fibers are the axons of presynaptic sympathetic neurons?

Answer 4

Motor (p.58)

Question 5

Through which roots do the axons of presynaptic sympathetic neurons leave the spinal cord?

Answer 5

Anterior roots (p.58)

Question 6

The fibers of presynaptic sympathetic neurons enter the _____ rami of spinal nerve ____ - _____.

Answer 6

Anterior rami of spinal nerves T1-L2,3.

p.58

Question 7

All presynaptic sympathetic fibers leave the _____ rami of spinal nerves and pass to the sympathetic trunk via ________.

Answer 7

Anterior rami via WHITE RAMI COMMUNICANTES.

p.58

Question 8

Presynaptic parasympathetic fibers that innervate what body parts will almost always synapse within a paravertebral ganglion (i.e. will not go to the prevertebral ganglia)?

-5 places in general.

Answer 8

Head, neck, body wall, limbs, and thoracic cavity.

p.59

Question 9

Where are the cell bodies on neurons that provide sympathetic innervation to the head (including the dilator pupillae)?

Answer 9

The superior cervical ganglion (at superior end of sympathetic trunk).
-p.62

Question 10

The cell bodies of somatic motor and presynaptic visceral motor neurons are located where?

Answer 10

Gray matter of the spinal cord. BUT WHICH PART???

-p.52

Question 11

The cell bodies of pseudounipolar (sensory) neurons are located where?

Answer 11

In sensory ganglia OUTSIDE the CNS.

-p.46

Question 12

1. ) Preganglionic fibers of ANS are myelinated/unmyelinated?
2. ) Post?

Answer 12

1. ) Preganglionic fibers of ANS are MYELINATED.

2. ) Postganglionic fibers of ANS are UNMYELINATED.

Question 13

Where are the cell bodies of presynaptic sympathetic neurons?

Answer 13

IMLs (p.58)

Question 14

The anterior rami of which spinal nerves levels generally do not form plexuses?

Answer 14

T2-T12. Along with all POSTERIOR RAMI.

p.52 caption.

Question 15

Posterior rami of spinal nerves are distributed where? (Three places in general).

Answer 15

Synovial joints of vertebral column, deep muscles of the back, and the overlying skin.
p.52 caption.

Question 16

The somatic nervous system innervates only _______.

Answer 16

Skeletal muscle.

p.57

Question 17

Where are the cell bodies are motor neurons located?

Answer 17

Anterior horn of gray matter (random anatomy book and wiki)

Question 18

1. ) Where do the axons of somatic sensory nerves enter the CNS?
2. ) Where are the cell bodies of somatic motor neurons located?
3. ) Where do the somatic sensory and motor neurons synapse with one another? i.e. Am i asking about reflexes? I think… Then where is the communication between sensory and motor, and where does the “integration” occur?

Answer 18

1. ) Posterior horn of gray matter.
2. ) Anterior horn of gray matter.
3. ) Lateral horn????? I DON’T KNOW!!!! aka Spinal cord integrating center? Interneuron?

Internuncial (connector) neurons in the posterior horn?

Yep, ok: Once the afferent signal arrives at the posterior (dorsal) horn of gray matter from the DRG to the posterior (dorsal) root, it arrives at a posterior horn cell (INTERNUNCIAL NEURON). The internuncial cell sends a short axon through the gray matter to an ANTERIOR HORN CELL in the neighborhood. Thus completing an afferent-efferent circuit/arc.

Question 19

There are no white rami below…

Answer 19

L2/3

Question 20

Which cranial nerves carry parasympathetic innervation?

Answer 20

CN: 3, 7, 9, 10

Question 21

EVERY peripheral nerve carries what type of innervation?

Answer 21

Sensory, motor, and SYMPATHETIC INNERVATION