Peripheral Nervous System

There are ____ pairs of spinal nerves and ____ pairs of cranial nerves in the peripheral nervous system

31; 12

The neural tube primarily develops into the _____ nervous system

Central

Neural Crest Cells primarily develop into the _____ and other ______

PNS; non-nervous system structures

Sensory nerves can be referred to as ____ nerves

afferent

Motor nerves can be referred to as ____ nerves

efferent

Nerve types can be further subdivided based on target:

somatic (body wall)

visceral (organs)

Cranial nerves exist in _____ _____ which exit the cranial cavity through openings called _____

bilateral pairs

formina

The Vagus nerve is cranial nerve ___

X

Spinal nerves are numbered with ____ ____ while cranial nerves are numbered with ____ ___

arabic numerals

roman numerals

Spinal nerves exit the vertebral column via _____ _____

intervertebral formina

There are ____ cervical vertebra, and are denoted by the letter _____

7; C

C1-C7 are named for vertebra _____ to their exit, so C8 exists between ____ and ____

inferior; C7 and T1

Besides cervical nerves, all are named by the vertebra ____ to their exit.

Superior

Fibers emerge from the spinal cord as ____

rootlets

Rootlets converge to form 2 _____ ____

nerve roots

The anterior (ventral) root relays ____ information and is composed of fibers from _____ _____ located in the ____ ____ of the spinal chord

motor

cell bodies

anterior horn

The Posterior (dorsal) root relays ___ information and is composed of fibers from ___ ____ located in the ___ ___ ____.

sensory

cell bodies

dorsal root ganglion

Nerve roots converge to form ____ ____ at or near the ______ ______

spinal nerve

intervertebral column

Nerve roots converge to form what? with what types of fibers?

spinal nerve, mixed (sensory and motor)

The spinal nerve immediately divides into the ______ _____ and _____ ____

Posterior (dorsal) ramus

Anterior (ventral) ramus

The posterior rami remain _____ the entire length of the spinal cord

separate

Function of dorsal rami

carry somatic motor, sensory, and postganglionic sympathetic fibers at ALL 31 SPINAL LEVELS

What 3 things to the posterior rami innervate

deep muscles of the back

skin overlying those muscles

arteries supplying these structures

Function of the anterior rami

carry somatic motor, sensory, and postganglionic sympathetic fibers at ALL 31 SPINAL LEVELS

What 2 things do the anterior rami innervate

anterior and lateral trunk

upper and lower limbs

ventral rami form ____ for the limbs

plexuses

Plexi of the ventral Rami and what they innervate:

brachial

cervical

sacral and lumbar

arm

neck

lower limb

Most peripheral nerves arising from a plexus contain fibers from ________

multiple spinal levels

Nerves of the anterior rami that participate in plexus formation contribute fibers to ______ _____ nerves arising from the plexus

multiple peripheral

Somatic motor fibers innervate ______

skeletal muscle

Somatic sensory fibers come from ____, ____, _____

skin, joints, muslce

Postganglionic sympathetic fibers innervate _______

smooth muscle of arteries and sweat glands

Despite being named sensory or motor, peripheral nerves still have:

both fiber types; the name depends on the majority fiber type

Spinal nerves supply the ___ and _____. But they do not supply structures within the _____ ____

body wall

limbs

body cavities

location of 1st order cell bodies in the afferent nervous system

outside of but close to the CNS

Lower motor neuron cell bodies of the efferent system are located where? where are some specific places?

gray matter of the CNS

ventral or lateral horns of the spinal cord

nuclei of the brain stem

The somatic system convayes information between _____

the CNS and body wall and cavities

The visceral system conveys information between _____

the CNS and internal organs, glands, and blood vessels

Input and what is carried by somatic sensory system

input from CNS to skin, joints, or skeletal muscle

pain temp touch pressure, proprioception

1st order cell body of somatic sensory system is in a _____

dorsal root ganglion

Where is the synapse in the sensory ganglion?

trick question, there is not one, its one cell

Unilateral area of skin innervated by the somatic sensory fibers of a single spinal nerve

dermatome

Dermatomes are labeled with ____

a letter and number representing the spinal nerve supplying that area of skin

If a dermatome lesion occurs at the level of the spinal nerves or posterior roots, generally at least ____ adjacent spinal nerves must be interrupted to produce a noticeable area of numbness.

2

Dermatome fibers generally _____ , resulting in a type of back-up system

overlap

______ formation results in different nerves carrying fibers from a single ____ ____, but the sensory fibers from this spinal nerve will ultimately be distributed to the same ______

plexus

spinal nerve

dermatome

Landmark Dermatomes

T4: nipple

T10: umbilicus

C5: lateral arm

target of the somatic motor system

skeletal muscle

There is only one neuron between CNS and target in he somatic motor system, known as the _____ _____ _____

lower motor system

where is the cell body located in the somatic motor sytem

in a nucleus within the ventral hoen of spinal chord or within nuclei of the brainstem

location of the cell bodies in preganglionic ANS neurons

within grey matter of CNS

Location of cell bodies of postganglionic ANS neurons

outside the CNS

Vasoconstriction is associated with ____ innervation

sympathetic

Where do parasympathetic fibers NOT go

to the body wall or limbs

where to sympathetic fibers go?

everywhere

Which visceral motor sytem innervates "simple" structures like sweat glands and arteries?

sympathetic

Where do 1st order visceral sensory cell bodies reside?

spinal/dorsal root ganglia OR specific cranial nerve ganglia

What increases the likelihood that a neuronal cell body can regenerate?

if the cell body is intact

Stretched nerves are often associated with what injuries?

bone fractures or dislocations

What nerve injury is most probable for regeneration?

crush

what type of nerve injury is associated with loss of blood supply to the nerve?

compression

damage to one or more of the nerves outside of the brain and spinal chord

peripheral neuropathy

The presence of visceral and somatic sensory cell bodies in the dorsal root ganglia is the basis for _____

referred pain

Give rise to specific head and neck structures: otic, nasal, and lens

ectodermal placodes

C4 innervation

lateral neck/superior shoulder

C5 innervation

lateral arm

C6 innervation

lateral forearm and thumb

C7 innervation

middle and ring fingers

C8 innervation

little finger

T1 innervation

medial forearm

T2 innervation

medial arm

T/F: The visceral motor system is also known as the autonomic nervous system

T

T/F: The autonomic nervous system is also known as the sympathetic nervous system

F