E3 Ch. 15 Flashcards
what is the ANS and what does it innervate
a system of motor neurons, is the general visceral division of PNS, innervates smooth muscle, cardiac muscle, and glands
what visceral functions does the ANA regulate
HR, BP, digestion, and urination
what two chain of motor neurons does the ANS have
preganglionic neuron and postganglionic neuron
why is conduction slower in the ANS vs the somatic NS
axons are thinly myelinated/non-myelinated, and motor neuron synapses in a ganglion
sympathetic and parasympathetic divisions of the NS work together to cause what types of effects
opposite
during extreme situations (i.e. fear, rage, exercise, etc.) ___ division mobilizes the body, AKA “fight or flight”
sympathetic
___ division controls routine maintenance functions
parasympathetic
what are some changes that happen to the body during extreme situations where the sympathetic division is initiated
increased HR, breathing rate, increased blood/oxygen to skeletal muscles, vasoconstriction of other blood vessels, dilate pupils and bronchioles, and inhibit motility of digestive and urinary tracts
when is the parasympathetic division active
when body is at rest
which does the thoracolumbsr division and craniosacral division belong to
thoracolumbar= sympathetic
craniosacral= parasympathetic
compare the length of postganglionic fibers b/t sympathetic and parasympathetic divisions
sympathetic-long
parasympathetic- short
compre the branching of fibers b/t sympathetic fiber and parasympathetic fibers
sympathetic fibers- highly branched (influence many organs at once)
parasympathetic fibers-few branches (localized effect)
compare the types of neurotransmitters released by postganglionic axons b/t the sympathetic and parasympathetic NS
sympathetic- norepinephrine (adrenergic)
parasympathetic- acetylcholine (cholinergic)
where does the cranial outflow of the parasympathetic division originate and what does it innervate
originates from brain, innervates organs of head, neck, thorax, and abdomen
what does the sacral outflow of the parasympathetic division innervate
remaining abdominal and pelvic organs
preganglionic fibers from the cranial outflow run via which set of nerves
oculomotor (III), facial (VII), glossopharyngeal (IX), and vagus (X)
what do the parasympathetic fibers innervate, where are preganglinic and postganglionic cell bodies locateed in the oculomotor nerve
parasympathetic fibers innervate smooth muscles in eye (pupil constriction)
preganglionic cell bodies located in oculomotor nucleus in midbrain
postganglionc cell bodies lie in ciliary ganglion
facial nerve; what do parasympathetic fibers stimulate, lacrimal nucleus location, and superior salivatory nucleus location
parasympathetic fibers stimulate secretion of glands in head
lacrimal nucleus located in pons, synapse in pterygopalatine ganglion
superior salivatory nucleus located in pons, synapes in submandibular ganglion
glossopharyngeal nerve; parasympatheic fibers stimulate, lacrimal nucleus location, areas of synapse
stimulate secretion of glands in head
lacrimal nucleus located in pons
synapse in pterygopalatine ganglion, and submandibular ganglion
what doe the outflow via the vagus nerve innervate
visceral organs of thorax and most of the abdomen
what does outflow via the vagus nerve stimulate
digestion, reduction in HR, and BP
where are the preganglionic cell bodies of outflow via the vagus nerve located
dorsal motor nucleus in medulla
where are postganglionic neurons of outflow via the vagus nerve located
confined w/in walls of organs being innervated, cell bodies form intramural ganglia
vagus nerves send branches though what plesuses?
autonomic nerve plexuses (cardiac, pulmonary, esophageal, celiac, and superior mesenteric plesuses)
where does sacral outflow emerge, and innervate
emerges from S2-S4, innervates organs of pelvis and lower abdomen
where are the preganglionic cell bodies of sacral outflow located
in visceral motor region of spinal gray matter
how do axons run in sacral outflow run, what do they form and run through
axons run in ventral roots to ventral rami, form pelvic splanchnic nerves, and run through inferior hypogastric plexus
what doe the preganglionic fibers of the sympathetic division form
lateral gray horn
what does the sympathetic division supply
visceral organs in internal body cavities and structures of superficial body regions
where are sympathetic trunk ganglia located, linked by, and other names
located on both sides of vertebral column, linked by short nerves into sympathetic trunks, AKA chain ganglia and paravertebral ganglia
sympathetic trunk ganglia are jointed to what by what
joined to ventral rami by white and gray rami communicantes
how does collateral ganglia differ from sympathetic trunk ganglia
- unpaired, not segmentally arranged
- occurs only in abdomen/pelvis
- lie anterior to vertebral column
name the main ganglia of collateral ganglia
celiac, superior mesenteric, inferior mesenteric, and inferior hypogastric ganglia
preganglionic neurons in the thoracolumbar spinal cord of the sympathetic division send motor axons though
adjacent ventral root into spinal nerve, then white ramus communicans and to the associated sympthetic trunk ganglion
what are the 3 pathways that preganglionic axons of the sympathetic division follow
- synapses w/ postganglionic neuron at same level it exits
- axons ascends/descends in sympathetic trunk to synapse in another ganglion
- axon passes though sympathetic trunk and exits on splanchnic nerve
what does the gray rami contain
only postganglionic fibers traveling to peripheral structures, fibers nonmyelinated
what does the white rami contain
preganglionic fibers traveling to sympathetic trunk ganglia, fibers are myelinated
where do preganglionic fibers of sympathetic pathways to the head originate
in spinal cord at T1-T4, fibers ascend in sympathetic trunk, synapse in superior cervical ganglion
pathways to the head postganglionic fibers associated with large arteries carried to what structures
glands, smooth muscle, and vessels throughout the head
pathways to thoracic organs preganglionic fibers originate from
spinal levels T1-T6, synapse in nearest sympathetic trunk ganglion
pathway to thoracic organs postganglionic fibers run where
directly to organ supplied
function of sympathetic fibers to throracic organs
increase HR, dialte bronchioles, dilate blood vessels to heart wall, inhibit muscles and glands in the esophagus and digestive system
describe the pathway of somatic motor innervation
- cell body located in ventral horn of gray matter
2. long axon extends from ventral root- innervate skeletal muscle cell
describe the pathway of sympathetic division of ANS innervation
- cell body of preganglionic neurons located @lateral horn of gray matter (T1-L2)
- preganglionic axon synapse w/ postganglioic neuron @peripheral ganglion
- long postganglionic axon from peripheral ganglion to target organ
- same time preganglionic axons emrege T8-L1 to innervate adrenal medulla, release epinephrine and noreepinIIephrine into surrounding capillaries
describe the pathway of parasympathetic division of ANS innervation
- cell bodies of preganglionic neurons located @gray matter of brain stem (CN III, VII, IX, X) and sacral region (S2-S4)
- preganglionic axon synapse w/ postganglionic neuron close/w/in target organ
- short postganglionic axon innervates target organ
preganglionic fibers in the pathway to abdominal organs originate where
T5-L2
preganglionic fibers in the pathway to the pelvic organs originate where
T10-L2
what is the role of the adrenal medulla in the sympathetic division
major organ, constitutes largest sympathetic ganglia, secrete noreepinephrine and epinephrine
what types of sensations do general visceral sensory neurons monitor w/in visceral organs
stretch, tempt, chemical changes, irritation
where are the cell bodies of general visceral sensory neurons located
dorsal root ganglion
no pain results when visceral organs are cut so when does visceral pain result
from chemical irritation or inflammation, often perceived to be of somatic origin
what participates in visceral reflex arcs
visceral sensory and autonomic neurons, some simple spinal reflexes, others don’t involve CNS (strictly peripheral reflexes)
what type of control is ANS under
not under direct voluntary control
what activities are regulated by CNS
brain stem, spinal cord, hypothalamus, amygdaloid body, and cerebral cortex
main integration center of the ANS
hypothalamus
function of the medial and anterior parts of the hypothalamus
direct parasympathetic functions
function of the lateral and posterior parts of the hypothalamus
direct sympathetic functions
amygdaloid body
main limbic region for emotions
raynaud’s disease
characterized by constriction of blood vessels, provoked by exposure to cold or by emotional stress
achalasia of the cardia
defect in the autonomic innervation of the esophagus
congenital megacolon (Hirschsprung’s disease)
birth defect, parasympathetic innervation of distal large intestine fails to develop correctly, feces/gas accumulate proximal to defect
where do the preganglionic neurons of the ANS develop from
neural tube
where do postganglionic neurons develop from
neural crest
