Peripheral Nerves

Question 1

Preganglionic Neuron

Answer 1

cell body in CNS

Question 2

Postganglionic Neuron

Answer 2

cell body in ganglion

Question 3

Mutlipolar neurons

Answer 3

CNS neurons- anterior horn motor neuron

Question 4

Bipolar neurons

Answer 4

Retina
Statoacoustic Nerve Ganglion
-special senses

Question 5

Unipolar neurons

Answer 5

posterior root ganglia

cranial nerve ganglia

Question 6

Somatic Afferent:

• _____ sensibility from ____ (monitors external environment)
• -P___
• -T___
• -T___
• -C___P___
• —-awareness of limb position

Answer 6

• exteroceptive sensibility from skin
• pain
• touch
• temperature
• conscious proprioception

Question 7

Somatic Efferent:

• allows for ____ with _____ environment
• -controls of ________

Answer 7

• interaction with external environment

- controls striated (voluntary) mm

Question 8

Visceral Efferent:

• allows for ____ of _____ environment
• -autonomic efferent
• –2 ____ chain
• —______ neuron: cbo within CNS
• —______ neuron: cbo in autonomic ganglion
• contraction of _____ mm
• secretion of _____

Answer 8

• control of internal environment
• –2 neuron chains= preganglionic and postganglionic
• contracts smooth mm
• secrets glands

Question 9

Visceral Afferent:

• _____ _____= monitors internal environment, e.g.
• -______afferent
• –heart rate
• –blood pressure
• –smooth mm contractility
• –bladder and bowel fullness

Answer 9

• visceral sensibility

- -autonomic afferent

Question 10

Posterior Horn

Answer 10

sensory

enters spinal cord

Question 11

Anterior Horn

Answer 11

motor

leaves spinal cord

Question 12

Myelin:

• membrane of ___ cells
• covers up to ____ of axon
• _____ axon membrane and increases ______ velocity

Answer 12

• glial cells
• 1cm
• insulates membrane and increases conduction

Question 13

Myelin producers:

Answer 13

• oligodendroglia cells (CNS)

- schwann cells (PNS)

Question 14

True or False:

The thicker and longer the internodal distance on an axon the slower the signal travels.

Answer 14

FALSE= the faster it travels

Question 15

Degeneration of Axon:

• crushed
• -myline degenerates
• -____break
• -____ and _____ ___ remains intact
• -______ enters from capillaries

Answer 15

• -axon breaks up
• -endoneurium and schwann cells still intact
• -monocytes enter from capillaries
• –macrophage cells engulf debris

Question 16

Regeneration of Axon:

• ___ developes sprouts
• ___ undergo mitosis
• growth cone tip follows surface cues
• schwann cell attends to segment of new axon

Answer 16

• axon develops sprouts

- schwann cell undergoes mitosis

Question 17

Damaged neuron will degenerate:

True or False- it will have less velocity(slower) then the original neuron

Answer 17

TRUE

Question 18

A-alpha (I) nerve fiber

Answer 18

very fast
alpha motor
myotatic reflex (thick myline coated)

Question 19

A-beta (II) nerve fiber

Answer 19

fast

deep touch

Question 20

A-delta (III) nerve fiber

Answer 20

slow

light touch, fast pain

Question 21

(IV) nerve fiber

Answer 21

very slow

slow pain

Question 22

Neuromuscular Spindle:

• lies _____ to muscle fibers
• consists of:
• -_____ ____
• –annulospiral ending
• –A alpha sensory fiber
• -adjacent to ____ ___ is _____ mm fibers (do not move limb just change tension)
• –____ motor neurons
• –increases tension on ____ ____
• ______ mm fibers= move limb; innervated by ___ motor neurons

Answer 22

• lies parallel
• -nuclear bag
• -adjacent to nuclear bag is intrafusal mm fibers
• –gamma motor neurons
• extrafusual; by alpha motor neurons

Question 23

Lower Motor Neuron

Answer 23

located in the ventral horn of the spinal cord (spinal lower motor neurons) or the cranial nerve nuclei of the brainstem (cranial n. lower motor neurons)

Question 24

Areflexia (LMN lesion)

Answer 24

-no reflex

Question 25

Atonia (LMN lesion)

Answer 25

-no mm tone

Question 26

Fasciculations (LMN lesion)

Answer 26

-mm undergo spontaneous contractions; both the mm and nerve die

Question 27

Muscle Atrophy (LMN lesion)

Answer 27

-mm degenerates

Question 28

LMN lesion results in (3)

Answer 28

- peripheral n - anterior root - anterior horn motor neuron (degenerates)

Question 29

Myasthenia Gravis

Answer 29

autoimmune disease -antibodies block acetylcholine receptors at neuromuscular junction (risk-F age 20-40)