Nervous System: Autonomics & Cranial Nerves

somatic is __ while autonomic is __ (voluntary/involuntary)

somatic is voluntary while autonomic is involuntary

sympathetic and parasympathetic pathways are ___ (autonomic or somatic)

autonomic

describe somatic neuron chain (CNS, PNS, Effector)

single neuron chain, myelinated, releases ACh, always stimulates skeletal muscle

describe somatic neuron chains (CNS, PNS, Effector)

can be a two neuron chain (preganglionic, postganglionic) or a neuron chain connected to adrenal medulla that releases hormones into blood; stimulates or inhibits smooth muscle, cardiac muscle, or epithelia

describe sympathetic vs parasympathetic chains

parasympathetic: pre-ganglionic is short and releases acetylcholine, post-ganglionic is long and releases norepinephrine (or if adrenal medulla, releases norepinephrine and epinephrine into blood)

sympathetic: pre-ganglionic is long and releases acetylcholine, post-ganglionic (intramural ganglion) is short and releases acetylcholine

pre-ganglion of sympathetic releases ___, which causes release of ___ in post-ganglion

acetylcholine, norepinephrine

pre-ganglion of sympathetic releases ___, which causes release of ___ by adrenal medulla

acetylcholine, norepinephrine and epinephrine

pre-ganglion of parasympathetic releases ___, which causes release of ___ in post-ganglion (intramural ganglion)

acetylcholine, acetylcholine

___ are innervated by sympathetic neurons that secrete ___, not norepinephrine

eccrine sweat glands, acetylcholine

parasympathetic neurons in cranial nerves III, VII, and IX end in ___ ganglia, not intramural ganglion

terminal

what is the origin of parasympathetic neurons?

craniosacral

__ nerve is most parasympathetic innervation

vagus

what is the origin of sympathetic neurons?

thoracolumbar

what is only innervated by sympathetic neurons?

skin, peripheral blood vessels, adrenal glands, kidneys

The cell bodies of sympathetic presynaptic neurons originate in the ___ region of the ___

thoracolumbar, spinal cord

Axons exit the spinal cord via the ___, which merges with the dorsal root to form ___

ventral root, spinal nerve

In the thorax, these nerves travel laterally between the ribs, and so are called ___

intercostal nerves

Sympathetic presynaptic neurons exit the spinal nerves via the white __.

rami communicantes

why are presynaptic neurons white?

myelinated

The white rami communicantes each connect to a ___ in the ___

sympathetic chain ganglion, sympathetic chain

describe 6A: End at its synapse with the postsynaptic neuron. The postsynaptic neuron then returns to the spinal nerve via a ___, then proceeds to ___

grey ramus communicans, peripheral targets (like skin or blood vessels to skeletal muscles)

postsynaptic neurons are ___, giving a ___ appearance

unmyelinated, grey

describe 6B: Continue superiorly or inferiorly along the __ to the next ganglion

sympathetic chain

describe 6C: continue medially into __

splanchnic nerve

Splanchnic nerves connect to the ___, where presynaptic neurons end at their synapses with postsynaptic neurons to ___.

prevertebral ganglia, visceral organs

Found inferior to the intercostal vein and artery running below each rib.

intercostal nerve

___ carry axons of presynaptic sympathetic neurons from the intercostal nerve to the sympathetic chain. These neurons are ___, giving them a __ appearance

White rami communicantes, myelinated, white

___ carry axons of postsynaptic sympathetic neurons from the sympathetic chain back to the intercostal nerve. These neurons are ___, giving a __ appearance

Grey rami communicantes, unmyelinated, grey

a band of nerve fibers that runs vertically along the side of the vertebral column

sympathetic chain

swellings on the sympathetic chain, connected to one or two rami communicantes

sympathetic chain ganglia

traveling from their origins at the sympathetic chain ganglia medially and inferiorly across the vertebral column towards their destinations at the prevertebral ganglia

splanchnic nerves

__ are nerves that carry autonomic neurons to visceral organs

splanchnic nerves

Splanchnic nerves from the thoracolumbar spinal cord carry __. In contrast, pelvic splanchnic nerves from the sacral spinal cord carry __

sympathetic neurons, parasympathetic neurons

The cell bodies of parasympathetic presynaptic neurons originate in the __

brain and the sacral region of the spinal cord

Presynaptic neurons in cranial nerves III, VII, and IX end in __

ganglia in the head (parasympathetic ganglia)

postsynaptic neurons from cranial nerves III, VII, and IX innervate the __

eye, lacrimal glands, salivary glands, and mucosa of the nasal and oral passages

Presynaptic neurons in ___ travel directly to their target organs and synapse at microscopic intramural ganglia.

vagus nerve

The vagus nerve thus provides the parasympathetic innervation for all visceral organs from the ___ to the ___

superior airway, midgut

Presynaptic neurons from the sacrum travel through ___ to ___ in their target organs.

pelvic splanchnic nerves, intramural ganglia

The source of parasympathetic innervation from the neck to the midgut is the ___

vagus nerve

this is an image of

intramural ganglion

CNI

olfactory nerve

A structure of the central nervous system often confused with CNI

olfactory bulb

functions of olfactory bulb

smell (ability to detect odor)

if delicate fibers of olfactory nerve broken, may result in __

loss of smell (anosmia)

CNII, travels from __ to __

optic nerve, travels from optic chiasm to the optic canal

CNII targets

retina

function of CNII

visual acuity

lesion of CNII

loss of visual acuity, blindness

CNII is vulnerable to __

disorders of the CNS (ex. multiple sclerosis) because an outgrowth of CNS (tract of axonx in CNS)

CNIII, travels from ___ to ___

oculomotor nerve, travels from brainstem to superior orbital fissure

functions of CNIII

somatic motor to most extraocular muscles (moving the eye), parasympathetic motor to the pupillary sphincter and ciliary muscle, eye movements, pupillary light reflex

lesion of CNIII can cause

diplopia (double vision), mydriasis (dilated or blown pupil), photophobia, cycloplegia (blurred near vision due to flattened lens)

CNIV, very thin and delicate, emerges from ___ and wraps along ___

trochlear nerve, emerges from posterior brainstem and wraps anteriorly along the fold of dura mater at the medial edge of middle cranial fossa

CNIV function

somatic motor to superior oblique muscle, eye movements

lesion of CNIV

diplopia (double vision)

CNV, emerges from ___ and pierces the ___

trigeminal nerve, emerges from anterior brainsterm and pierces the dura mater

three branches of the trigeminal nerve

V1 (ophthalmic), V2 (maxillary), V3 (mandibular)

CNV functions

somatosensation (sense of touch) from face, motor to muscles of mastication (chewing) and some muscles of the pharynx, bite strength

___ is a condition in which the trigeminal nerve transmits intense pain impulses to the brain

Trigeminal neuralgia

lesion of CV

(-) numbness or (+) pain, tingling, and difficulty chewing

CNVI

Abducens nerve

CNVI functions

somatic motor to lateral rectus muscle

CNVII, travels together with ___, from the ___ to the ___

facial nerve, travels together with CNVIII, from the lateral brainstem to the internal auditory meatus

CNVII function

facial expressions

lesion of CNVII

weakness/paralysis, xerophthalmia (dry eye), loss of taste, Bell’s palsy (drooping facial expression due to weakness or paralysis)

CNVIII

vestibulocochlear nerve

CNVIII functions

hearing from cochlea, balance and equilibrium from vestibular apparatus

lesion of CNVIII

loss of hearing and balance, tinnitus and vertigo, nausea

CNIX

glossopharyngeal nerve

CNIX functions

taste and touch from posterior 1/3rd of the tongue and pharynx, also visceral sensation from carotid baro and chemoreceptors, some motor to the throat and parotid gland, swallowing and gag reflex

lesion of CNIX

numbness at pharynx, loss of sensation & taste from post. tongue

CNX

vagus nerve

CNX functions

parasympathetic motor to the heart, airways, foregut, and midgut; also somatosensation (touch) and motor innervation to pharynx and larynx, visceral sensation from aortic baro and chemoreceptors, some taste from pharynx, swallowing

lesion of CNX

dysphagia (difficulty swallowing), dysphonia (hoarseness), tachycaria (increased heartrate)

CNXI

accessory nerve

CNXI functions

somatic motor to sternocleidomastoid and trapezius muscles (shrugging), ability to shrug and turn head v. resistance

lesion of CNXI

atrophy of trapezius, weakness in elevation of scapula & rotation of neck

CNXII, starts ___ and travels to ___

hypoglossal nerve, starts deep down brainstem and travels to hypoglossal canal

CNXII functions

somatic motor to tongue, movement of tongue

lesion of CNXII

dysarthria (slurred speech)

identify

intramural ganglion is ___ (parasympathetic or sympathetic)

parasympathetic

rest and digest

parasympathetic

fight or flight

sympathetic

parasympathetic or sympathetic: when eye constricts pupil & lens (near vision)

parasympathetic

parasympathetic or sympathetic: eye dilates pupil and relaxes lens

sympathetic

parasympathetic or sympathetic: salivary glands stimulates secretion

parasympathetic

parasympathetic or sympathetic: salivary glands stimulates secretion (direct effect), overwhelmed by decreased blood flow

sympathetic

parasympathetic or sympathetic: constrict airways

parasympathetic

parasympathetic or sympathetic: dilates airways

sympathetic

parasympathetic or sympathetic: decreases heart rate and contractility

parasympathetic

parasympathetic or sympathetic: increases heart rate & contractility

sympathetic

parasympathetic or sympathetic: increases secretion and motility of the GI organs

parasympathetic

parasympathetic or sympathetic: decreases secretion and motility of the GI organs

sympathetic

parasympathetic or sympathetic: increases liver glucose uptake

parasympathetic

parasympathetic or sympathetic: stimulates liver glucose release

sympathetic

parasympathetic or sympathetic: stimulates bladder contraction and urination

parasympathetic

parasympathetic or sympathetic: inhibits bladder contraction and urination

sympathetic

parasympathetic or sympathetic: stimulates erection

parasympathetic