Nervous System Review & Cranial Nerves

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Divisions of Nervous System by Location

Divisions of Nervous System by Location

CNS and PNS

CNS

brain and spinal cord (motor & sensory components)

PNS

31 pairs of spinal nerves (motor and sensory components) and 12 cranial nerves (motor or sensory or both)

Divisions of Nervous System by Function

somatic (voluntary & reflex), visceral (autonomic, involuntary), and enteric(nervous tissue within intestinal tract)

Visceral components

parasympathetic(rest and digest) and sympathetic (fight or flight)

enteric nervous tissue

nervous tissue within intestinal tract, can act independently of CNS or ANS

Divisions of nervous system by development

somatic, visceral, and branchial

Somatic Division

skeletal muscle efferent and general sensory afferent

Visceral Division

smooth muscle efferent and general visceral afferent

Branchial Division

skeletal muscles of head and neck derived from branchial arches

Motor Nurons Efferent are

multipolar

Afferent Sensory neurons are

unipolar

Somatic Structures derive from

Embryonic paraxial somites (ex skeletal muscles)

Visceral Structure include

gut, heart, lungs, glands, genitourinary systems & glands

Branchial Structures develop from

branchial arches of the embryo

Things that develop from somatic cells

eye, ear, nerve cord, notochord, trunk wall, tail, and skeletal muscle

Things that develop from visceral portion

jaws, pharynx, gut, and associated parts including branchial mm

What nerve innervates the 1st branchial arch

trigeminal N (CNV)

what nerve innervates the 2nd arch

facial N (CNVII)

what nerve innervates 3rd arch

glossopharyngeal N (CNIX)

what nerve innervates the 4th and 6th arch

Vagus N (CNX)

What nerve innervates the 5th arch?

No nerve, no arch

What develops from arch 1?

malleus and incus

What develops from arch 2?

stapes and stylohyoid ligament

What develops from arch 3?

hyoid body

What develops from arch 4?

thyroid cartilage and cricoid cartilage

General Visceral Efferent Motor Nerves (GVE)

autonomic fibers to smooth and cardiac muscle, parasympathetic for cranial and sacral nerves, sympathetic for spinal nerves in thoracic and lumbar regions

General Somatic Efferent motor nerves (GSE)

innervate skeletal muscles derived from somites

T/F all spinal nerves have GVE and GSE Fibers

True

Special Visceral or Branchial Efferent motor nerves (SVE or BE)

innervate striated muscles derived from branchial arches

Where are SVE or BE branches found?

In cranial nerves V, VII, IX, X, XI

General Somatic Afferent sensory nerves (GSA)

touch, pain, heat loss/gain, & proprioception from the body

General visceral afferent sensory nerves (GVA)

touch, pain, and proprioception from viscera

T/F all spinal nerves have GSA and GVA fibers

True

Special Visceral Afferent nerves (SVA)

olfaction and taste

where are special visceral afferent nerves found?

cranial nerves I, VII, IX, and X

Special Somatic Afferent Nerves

vision and hearing/equilibrium

where are special somatic afferent nerves found?

cranial nerves II and VIII

autonomic nervous system

control of involuntary/subconscious regulation of visceral effector organs: smooth muscle, cardiac muscle, glands

How many neurons are required for a motor response

2, pre and post ganglionic fibers

Sympathetic Division of Autonomic Nervous System (SANS)

fight or flight response

What nervous outflow to paravertebral ganglia

thoracolumbar (T1-L2)

Parasympathetic Division of Autonomic Nervous System (PANS)

rest and digest function

Craniosacral outflow of PANS

CNIII, VII, IX, X to cranial autonomic ganglia and S2-4 outflow to prevertebral ganglia

Organization of ANS

brain, spinal cord, cranial nerves, spinal nerves, hypothalamus, medulla

hypothalamus

coordinates and maintains homeostasis, regulates and integrates visceral activity like heart rate, blood flow, glucose levels, gland secretion, GI motility

medulla

reflex center: cough, vomit, sneeze, respiration, hiccup, swallow

Sympathetic ganglia of head and neck

superior cervical ganglion

Parasympathetic 4 cranial ganglion

ciliary, pterygopalatine, submandibular, and otic

CNIII ganglion

Ciliary ganglion

CN VII ganglions

pterygopalatine ganglion and submandibular ganglion

CN IX ganglion

Otic ganglion

CN I skull foramina

cribiform plate

CN I nuclei

mitral cells of olfactory bulb

CN I function and distribution

special sensory smell, there are thousands of olfactory nn passing through the cribiform plate to the bulb

CN II skull foramina

optic canal

CN II nuclei

retinal ganglion cells

CN II function and distribution

special sensory vision, deep in retina about 1.5 million ganglia cells transmit sensory info through the optic N

CN III skull formina

superior orbital fissure

CN III nuclei

oculomotor and endinger-westphal

CN III action, occulomotor nuclei

somatic motor to most extrinsic eyeball muscles

CNIII action, edinger-westphal nucleus

visceral motor (parasympathetic and sympathetic) to iris and ciliary muscles of eye

CNIV skull foramina

supraorbital fissure

CN IV Nuclei

Trochlear

CN IV function

somatic motor to superior oblique

CN V1 skull foramina

supraorbital fissure

CN V2 skull foramina

foramen rotundum

CN V3 skull foramina

foramen ovale

CN V nuclei

trigeminal nucleus and masticator nucleus

Action of trigeminal nucleus

general sensory from face, scalp, mucosa of oral and nasal cavities and pharynx

Action of masticator nucleus

branchial motor to muscles of mastication, anterior digastric, mylohyoid, tensor tympani, tensor veli palatini

CN VI foramina

supraorbital fissure

CN VI nuclei

abducens

CN VI action

somatic motor to lateral rectus

CN VII foramina

in auditory meatus, facial canal, stylomastoid foramen

CN VII nuclei

gustatory, trigeminal, facial nucleus, and superior salivatory

Gustatory nuclei action

special sensory taste of ant 2/3 of tongue

Trigeminal Nuclei action of VII

general sensory to external auditory meatus and ear

Facial Nucleus action

branchial motor to facial expressions muscle, stylohyoid, digastric posterior belly, stapedius

Superior Salivatory nucleus action

parasympathetic fibers to head gland EXCEPT parotid

CN VIII skull foramina

internal auditory meatus

CN VIII nuclei

cochlear and vestibular

Cochlear nuclei action

special sense hearing

Vestibular nuclei action

special sensory equilibrium