- spinal cord - medulla oblongata - pons - midbrain - thalamus - cerebral hemisphere

Unit 2 - ANS A&P Flashcards by Danielle Parker

makes up the CNS

spinal cord
medulla oblongata
pons
midbrain
thalamus
cerebral hemisphere

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included in cerebral hemisphere

cerebral cortex
subcortical white matter
basal nuclei

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peripheral nervous system consists of:

spinal and cranial nerves (except CN2) present outside CNS

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ultimate responsibility of ANS

ensure physiologic integrity of cells , tissues ,and organs througout the entire body despite challenges from external environment

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ANS division that accounts for miosis and eye accommodation

PNS

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3 divisions of the ANS

Sympathetic
Parasympathetic
Enteric divisions

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which anatomic part of the nervous system is surrounded and covered by meninges?

central nervous system

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which type of muscle does NOT receive ANS signals?

skeletal

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ANS division responsible for artery tone

SNS

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CV effects of SNS stimulation

increased cardiac force, rate, conduction, excitability
constriction and dilation of coronary arterioles

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pulmonary effects of PNS

bronchial smooth muscle contraction

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pulmonary effects of SNS stimulation

relaxation of bronchial smooth muscle

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eye effects of SNS stimulation

mydriasis (pupil dilation)
ciliary muscle relaxes (far vision)

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peripheral neurotransmitters of autonomic efferents

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peripheral NT of somatomotor efferents

ACh

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target organ(s) of somatomotor efferents

skeletal muscle

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nerve fiber classification of preganglionic autonomic efferents

lightly myelinated B fibers

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nerve fiber classfication of postganglionic autonomic efferents

nonmyelinated c fibers

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nerve fiber classification of somatomotor efferents

heavily myelinated A-alpha fiber

moderately myelinated A-gamma fibers

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control system of autonomic efferents

primarily unconscious, involuntary control
independent with hormonal control

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control system of somatomotor efferents

primarily conscious, voluntary control
unrelated to hormonal control

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neuron routes involved from spinal cord to target in somatic efferent pathways

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neuron routes involved from spinal cord to target in ANS efferent pathways

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schema for anatomic organization of ANS

origin → route to relay → relay → distribution → effector (target)

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2 synonyms for efferent

motor, outflow

3 structures that comprise brainstem

- medulla - pons - midbrain (mesencephalon)

2 synonyms for afferent

sensory, inflow

pathway assoc. with short preganglionic and long postganglionic fibers

SNS efferent pathways

SNS origin

preganglionic nerve cell body (soma)

characteristic feature of ANS

its efferents emerge as myelinated fibers from spinal cord or brain (CNS), are interrupted in course by synapse in a peripheral ganglion, and are then relayed for distribution as fine, nonmyelinated fibers to their effectors

nerve fiber classification of preganglionic neurons

lightly myelinated B fibers

nerve fiber classification of postganglionic neurons

unmyelinated C fibers

nerve fiber classification of A-alpha motor neurons

heavily myelinated, large fibers

nerve fiber classification of A-gamma motor neurons neurons

modestly myelinated, thinner fibers

where do sympathetic preganglionic neurons arise

thoracolumbar region T1-L2

where are cell bodies of preganglionic sympathetic fibers located

lateral hord of spinal cord grey matter, specifically within intermediate (IML) nucleus

where does the IML lie

Rexed's lamina 7

where do parasympathetic preganglionic neurons travel

CN 3, 7, 9, 10 and sacral roots S2-S4

which division of the ANS is called the craniosacral system

parasympathetic

origin of the somatomotor division

ventral horn of the spinal cord

location of cell bodies of alpha and gamma motor neurons

Rexed's laminae 8 and 9

where do axons of preganglionic SNS neurons leave the spinal cord

segmental level at which their cell bodies are located

what forms the white rami

preganglionic symapthetic axons exiting from ventral root

why are white rami white

preganglionic fibers are lightly myelinated B fibers and myelin imparts a white color

why are grey rami grey

axons are nonmyelinated - these areas contain nerve cell bodies, which are grey

where do white rami exist and why

only at T1-L3, where all preganglionic SNS fibers originate from

what is a nerve plexus

network of afferent and efferent nerve fibers from different spinal nerves

somatic nerve plexuses

- cervical - brachial - lumbar - sacral

visceral nerve plexuses

- cardiac - abdominal aortic - hypogastric

where are spinal levels gray rami found

all spinal cord levels

reflex characterized by increased HR in response to increased right atrial volume example

Bainbridge ex- autotransfusion during childbirth

enzyme that deactivates cAMP

phosphodiasterase

preganglionic fibers in SNS vs PNS

PNS - preganglionic: long, myelinated, B-fiber, releases ACh - postganglionic: short, unmyelinated, C-fiber, releases ACh SNS - pre: short, myelinated, B-fiber, releases ACh - post: long, unmyelinated, C-fiber, releases NE

origin of efferent SNS pathways

T1-L3 cell bodies arise from IML region of spinal cord (rexed's lamina 7)

where do efferent SNS fibers exit

ventral nerve roots

where do efferent SNS preganglionic fibers synapse with postganglionic fibers

in paired sympathetic ganglia (mass effect)

origin of efferent PNS pathways

CN 3, 7, 9, 10 S2-S4

where do preganglionic fibers synapse with postganglionic fibers in craniosacral division

near or in each effector organ (precise control of each organ)

innervation of adrenal medulla

no postganglionic innervation preganglionic axon takes a straight shot to adrenal medulla

sympathetic chain ganglia pairs

- 3 cervical (superior, middle, inferior) - thoracic 11-12 - lumbar 3-5 - sacral 3-5 - single coccygeal

what is the stellate ganglion

combination of inferior cervical ganglion & T1 ganglion

only splanchnic nerves to carry PNS fibers

pelvic splanchnic nerves

function of splanchnic nerves

deliver preganglionic SNS fibers to prevertebral delay ganglia and plexuses distribute postganglionic fibers

the intermediolateral nucleus lies within which of Rexed's lamina

white rami are found only at spinal cord levels:

T1-L2/L3

which ganglia are sites for sympathetic synaptic relays

sympathetic chain ganglia & prevertebral ganglia

what is a ganglion

a peripheral collection of nerve cell bodies (soma)

3 thoracic splanchnic nerves

1. greater 2. lesser 3. least

which plexus may be blocked for relief of pain due to chronic pancreatitis

celiac plexus

how do somatic sympathetic groups generally travel to effectors

via spinal nerves

where do preganglionic SNS neurons to adrenal medulla arise in spinal cord

IML T4-T12

where do ALL preganglionic sympathetic neurons arise from?

T1-L3

what is the largest sympathetic plexus

celiac

ganglia that are sites for sympathetic synaptic relays

sympathetic chain ganglia prevertebral ganglia

ganglion of spinal segment T1-2

superior cervical

provides SNS innervation to colon, urinary bladder, reproductive organs

lumbar sphanchnic nerves

what do postganglinoic axons of lesser splanchnic nerves innervate

GI tract, kidneys, bladder, reproductive organs

where do postganglionic fibers from cervical ganglia distribute

structures in head, neck, heart, lungs

what forms the greater splanchnic nerve

a group of visceral SNS preganglinoic nerves from T5-T9/10 that traverse the sympathetic trunk ganglia

function of greater splanchnic nerve

synaptic relays in the celiac and superior mesenteric ganglia from there, postganglionic fibers are distributed to upper GI via prevertebral plexuses

plexus with distribution to smooth muscle of esophagus

cardiac plexus

plexus with distribution of postganglionic sympathetic fibers to sigmoid colon

aortic & hypogastric

plexus with distribution of postganglionic sympathetic fibers to liver & gallbladder

celiac plexus

plexus with distribution to cardiac tissues

cardiac plexus

largest sympathetic plexus

celiac

plexus that lies at L1

celiac

plexus with distribution of postganglionic sympathetic fibers to reproductive organs

hypogastric plexus

another name for stellate ganglion

cervicothoracic ganglion

cranial nerves with PNS components

CN 3, 7, 9, 10

somatic efferents of oculmotor nerve

motor supply to certain extraocular skeletal muscles (levator palpebrae superioris, superior/medial/inferior rectus, inferior oblique

visceral (PNS) efferents of oculomotor nerve

innervate specific intraocular muscles (pupillary sphincter, ciliary muscle)

PNS component of facial nerve

Carries PNS efferent innervation to submandibular, sublingual, and lacrimal glands

main sensory component of CN 7

facial nerve carries taste from anterior 2/3 tongue via chorda tympani

motor components of CN 9

1) visceral efferents to pharyngeal constrictor skeletal muscles 2) visceral effects – PNS fibers – to parotid glands

sensory components of CN 9

1) somatosensory supplies to posterior 1/3 tongue, soft palate, pharyngeal mucosa, tonsils, eustachian tube, tympanic membrane, external ear 2) special visceral afferents from taste buds to posterior 1/3 tongue 3) general visceral efferents from carotid bodies and carotid sinus

supplies about 75% of PNS outflow to the body

CN 10

motor components of CN 10

1) visceral efferents to pharyngeal skeletal muscles, skeletal muscles of soft palate, and all laryngeal muscles 2) visceral efferents (PNS fibers) to thoracic & abdominal viscera

sensory components of CN 9

1) modest somatosensory supply to ear, dura of posterior fossa 2) special visceral afferents from tastebuds on the epiglottis 3) transmitting sensations from pharynx, larynx, barorecepors, chemoreceptors, thoracic & abdominal viscera

Origin of vagal efferents

nucleus ambiguous & dorsal motor nucleus

PNS outflow arises from spinal cord levels:

S2-S4

list the 4 relay ganglia for CN sympathetic pathways

ciliary (CN 3) pterygopalatine (CN 7) submandibular (CN 7) otic (CN 9)

postganglinoic PNS fibers of CN 7 & 9 reach targest by hitchhiking on branches of which nerve?

CN 5

5 nerve plexuses that distribute PNS fibers to viscera

pharyngeal cardiac pulmonary esophageal celiac

which CN is superior salivatory nucleus assoc with

CN 7

CN associated with inferior salivatory nucleus

CN 9

2 routes preganglionic fibers originating in superior salivatory nucleus can take

1. to pterygopalatine ganglion - petroal nerve = pterygopalatine relay ganglion 2. leave via facial n. in chorda tympani branch - joins lingual n. - submandibular ganglion

how do preganglionic fibers originating in inferior salivatory nucleus leave brainstem

with CN 9

most CNS neurons are multipolar are unipolar?

multipolar

where do cell bodies of pseudounipolar sensory neurons lie?

DRG

where do sympathetic efferent pathways start and end

start: CNS end: effector (target) organs

where do visceral afferent pathways start and end

start: organs end: CNS

what classification of nerve fibers are visceral afferents

A delta and C

visceral afferents from the heart travel in the vagus nerve to the:

NTS (nucleus tractus solitarius)

cell bodies of sympathetic afferent fibers are in the:

dorsal root ganglia

cell bodies of sympathetic afferent fibers are in the:

dorsal root ganglia

which CN with PNS components does NOT transmit sensory information

CN 3

noxioius visceral sensations generally travel in which division of ANS?

sympathetic

receptors that mediate majority of PNS physiologic effects

mAChRs

muscarinic receptors in PNS division

M1, M2, M3

muscarinic receptor assoc. with cerebral vasoconstriction

muscarinic receptor found in heart

muscarinic receptor assoc with bronchoconstriction

signal transduction of M2 & M4 receptors

Gi, G0

effectors of M2 & M4 receptors

inhibit adenylate cyclase

signal transduction of M1, M3, and M5

effector of M1, M3, and M5

PLC activation (Gq)

location of N-N receptors

autonomic ganglia adrenal medulla

muscarinic receptors that cause cerebral vasodilation

M2, M5

muscarinic receptors assoc with increased insulin secretion

location of M1 receptors

autonomic ganglia glands

location of N-N receptors

Autonomic ganglia Adrenal medulla

location of M2 receptors

Heart Smooth muscle ANS nerve terminals

location of M3 receptors

Smooth muscle Glands

muscarinic receptors assoc with increased Na+ permeability

what enzyme catalyzes the synthesis of ACh

ChAT - choline acetyltransferase

another name for en passant synapses

neuroeffector junctions

what is stored in postganglionic terminal varicosities

neurotransmitters

signal transduction of alpha 1 receptors

Gq/11

alpha 1 receptor effectors

activates PLC

signal transduction of alpha 2 receptors

Gi; G0

effectors of alpha 2 receptors

inhibit AC Calcium, K channels

signal transduction of beta receptors

effectors of beta receptors

stimulates AC calcium channels

alpha receptor assoc. with vasoconstriction of aorta and coronaries

alpha 1D

alpha receptors assoc with cardiac growth & remodeling

alpha 1B

alpha receptors in blood vessels, heart, lung, liver, smooth muscles, vas deferens, prostate

alpha 1A

molecular/cellular response of alpha 1 receptors

• Coupled to Gq to activate PLC = ↑ IP3/DAG • Modulate K+ channels • ↑ Na+/H+ exchanged

adrenergic receptor with central components of baroreceptor reflex

alpha 2A

molecular response of alpha 2A receptors

Coupled to Gi to inhibit AC = ↓ cAMP, PKA

predominant receptor for 2 mediated vasoconstriction

alpha 2B

location of alpha 2 C receptors

presynaptic sympathetic nerve terminals

adrenergic receptor assoc with decreasd NT release from adrena medulla

alpha 2C

adrenergic receptor that activates L type calcium channels

Beta 1

adrenergic receptor assoc with lipolysis in adipocytes & thermogenesis

beta 3

adrenergic receptor assoc with skeletal muscle glycogenolysis & hypertrophy

beta 2

adrenergic receptor responsible for melatonin synthesis

beta

SNS neurotransmission with postganglionic cholinergic fibers

exocrine glands

ACh released from postganglionic SNS to exocrine glands mainly binds to what receptor

how do sweat glands release sweat

exocytosis

co-released with NE from postganglionic fibers to decrease amount of NE released

NPY (neuropeptide Y)

co-localized with ACh in preganglionic neurons to regulate SNS activity at ganglia

co-released with NE for SNS stim of vascular smooth muscle

ATP

adrenergic receptor assoc with decreased preganglionic NE release

alpha 2

adrenergic receptor assoc with decreased preganglinoic ACh release

alpha 2

adrenergic receptor assoc with increased renin release

beta 1

intraocular muscle contraction that causes mydriasis

radial muscle

intraocular muscle contraction that causes miosis

spincter pupillae (circular) muscle

3 typical features of horners syndrome

1. miosis 2. partial ptosis 3. ipsilateral anhidrosis

what causes miosis in horners syndrome

paralysis of dilator pupillae muscle

what causes ptosis in horners syndrome

- paralysis of superior tarsal muscle of levator palaprae superior - ascending SNS outflow blockade at stellate ganglion

what causes ipsilateral anhidrosis in horners syndrome

absence of sweating d.t absence of innervation to sweat glands

innervates orbitalis muscle

superior cervical ganglion (SNS fibers)

cardioaccelerator nerves

T1-T4

complementary SNS & PNS innervation in salivary glands

- SNS = NE acts on alpha 1 and beta = thick secretions - PNS = CN 7 & 9 = copious watery secretions via ACh acting on M3

PNS only innervation

lacrimal glands, ciliary muscle (near vision accommodation), nasopharyngeal glands

SNS only innervation

adrenal medulla, most blood vessels, erector pili, gallbladder, kidney, exocrine sweat glands

most important integrator of ANS & endocrine function

hypothalamus

most important factors controlled by brainstem

arterial pressure, HR, resp control

major lower brainstem command center for visceral control

NTS in brainstem

greatest concentration of autonomic centers

hypothalamus

mediates interactions between limbic system and brainstem

hypothalamus

major lower brainstem control center for visceral control

NTS

ANS influences all tissues EXCEPT:

skeletal muscle tissues

1st line defense against arterial BP changes

baroreceptor reflex

procedures that affect baroreceptor reflex

CEA mediastinoscopy

what indicates that baroreceptor reflex is preserved

heart rate increases with hypotension or decreases with HTN

what is the bainbridge reflex

tachycardia r/t increased venous return

reflex that prevents damming or sludging of veins, atria, and pulm circulation

bainbridge

counterbalance to baroreceptor reflex

bainbridge

cardioinhibitory reflex

Bezhold-Jarisch

triad of bezhold jarisch reflex

Bradycardia, hypotension, & coronary dilation

↓ HR & BP during spinal epidural attributed to what reflex

Bezhold-Jarisch

strongest drive at peripheral chemoreceptors

hypoxia

what causes vasovagal syncope

- transient decreased perfusion to the brain - massive PNS stimulation, abolition of SNS tone

effector response of oculocardiac reflex

decreased activity of SA and AV nodes

Reflex that fatigues with subsequent occurrences

oculocardiac

what is the CNS ischemic reflex

blood flow to medullary vasomotor center decreases enough to cause cerebral ischemia massive SNS activation = vasoconstriction and increased BP

one of the most powerful of all activators of SNS vasoconstriction

CNS ischemic reflex

when does CNS ischemic reflex response become signifncant

MAP < 50

greatest degree of CNS ischemic reflex stimulation

MAP 15-20

control center for thermoregulatory reflexes

hypothalamus

how is nonshivering thermogenesis in newborns & infants modulated

by NE from adrenergic nerve terminals

what is the mass reflex

simultaneous excitation of all segmental spinal reflexes (autonomic hyperreflexia)

ANS influences all tissues EXCEPT:

skeletal muscle tissues

Unit 2 - ANS A&P Flashcards

(204 cards)