ANS Flashcards
synapses between preand
postganglionic cholinergic nerves are not blocked by
atropine _____________whereas the postganglionic impulses are blocked by atropine __________
(nicotinic)
(muscarinic) .
axons of the ciliary ganglion cells innervate the
_________ and __________
ciliary muscle
pupillary sphincter
The preganglionic fibers of the _____________ enter the facial nerve and, at a point near the
____________, form the greater superficial petrosal
nerve, through which they reach the _____________; postganglionic fibers from the cells of this
ganglion innervate the ____________
superior salivatory nucleus
geniculate ganglion
sphenopalatine ganglion
lacrimal gland
Axons of the_____________ enter the glossopharyngeal
nerve and reach the otic ganglion through the___________ and ________________ cells of the
otic ganglion send fibers to the parotid gland.
inferior salivatory nerve cells
tympanic plexus
lesser superficial petrosal nerve;
In organs containing smooth muscle that is innervated
by parasympathetic fibers and therefore not under
voluntary control, there is a parallel innervation of adjacent __________by anterior horn cells
voluntary striated muscle
that they are somatomotor, innervating the
skeletal muscle of the _________
external urethral and anal sphincters
T or F
the neurons
in the Onuf nucleus, in contrast to other somatomotor
neurons in the sacral cord, tend not to be involved in the
degenerative process
T
The axons of the
nerve fibers originating in the intermediolateral column
are of small caliber and are myelinated; when grouped,
they form the_______________
white comm un icating ram i
Axons of the sympathetic ganglion cells are also of
small caliber but are unmyelinated. Most of the postganglionicfibers pass via _______________to
their adjacent spinal nerves of ___________
gray communicating rami
T5 to L2;
The arm receives its postganglionic
innervation from the ___________
inferior cervical ganglion and
uppermost thoracic ganglia
The cardiac plexus and other thoracic
sympathetic nerves are derived from the ___________
and the abdominal visceral plexuses, from the _____________
stellate ganglion
fifth to the
ninth or tenth thoracic ganglia
In the brainstem, the
main visceral afferent nucleus is the_______
nucleus tractus solitarius
NTS
Cardiovascular, respiratory, and gastrointestinal
afferents, carried in cranial nerves X and IX via the
_______ and ________, terminate on specific subnuclei
of the NTS
nodose and petrosal ganglia
The supranuclear
regulatory apparatus of the hypothalamus includes three
main cerebral structures: ______, _______ and _______
the frontal lobe cortex, the insular
cortex, and the amygdaloid and adjacent nuclei
Stimulation of one ________ lobe may evoke changes in
temperature and sweating in the contralateral arm and
leg;
frontal
The insular cortex receives projections from the _______________
NTS, the parabrachial nucleus of the pons, and the lateral hypothalamic nuclei
The _______ and ___________
and their associated subcortical structures (substantia
innominata and the amygdaloid, septal, piriform, habenular, and midbrain tegmental nuclei) have been identified as important cerebral autonomic regulatory centers.
They are called _____________
cingulate and hippocampal gyri
visceral brain
__________ released from postganglionic fibers that end on pineal cells stimulates several enzymes involved in the
biosynthesis of melatonin.
norepinephrine
NE
Sympathetic responses are most readily obtained by
stimulation of the ___________ regions of the
hypothalamus, and parasympathetic responses from
the _________ regions
posterior and lateral
anterior
some structures-_________________-receive only
sympathetic postganglionic fibers, and the _______________
as indicated earlier, has only a preganglionic sympathetic
innervation.
sweat glands, cutaneous blood vessels, and hair follicles
adrenal gland,
Most of the neuropeptides exert
their postsynaptic effects through the _________, which uses ______________
as an intermediary.
G-protein transduction system
adenyl cyclase or phospholipase C
Adrenergic receptors are of two types, alpha and beta. In general, the alpha
receptors mediate __________________;
beta receptors mediate _________
vasoconstriction, relaxation of the gut,
and dilatation of the pupil
vasodilatation,
especially in muscles, relaxation of the bronchi,
and an increased rate and contractility of the heart.
Alpha1 receptors are postsynaptic; alpha2 receptors are
situated on the presynaptic membrane and, when stimulated_____________
diminish the release of the transmitter
Beta1 receptors
are, for all practical purposes, limited to the heart; their
activation increases ___________
the heart rate and contractility
_________ when stimulated, relax the smooth muscle of the bronchi and of most other sites, including the blood vessels of skeletal muscle.
Beta2 receptors,
In BP regulation,
Those in the ______________ are sensitive to
reductions in pulse pressure (the difference between systolic and diastolic blood pressure),
while those in the right
heart chambers and pulmonary vessels respond more to
_________
carotid sinus and aortic arch
alterations in blood volume
The____________ are rapidly responsive and capable of detecting beatto- beat changes,
in contrast to the ____________ which
have a longer response time and discriminate only the
larger and more prolonged alterations in pressure
carotid sinus baroreceptors
aortic arch nerves,
Increased systemic vascular resistance is mediated
concurrently through parallel connections between the
NTS and the medullary pressor areas that project to the
_________
intermediolateral cells of the mid thoracic cord
what are the Two slower-acting humoral mechanisms regulate blood volume and complement the control of systemic vascular resistance
- Pressure-sensitive renal juxtaglomerular
cells release renin, which stimulates production of
angiotensin and influences aldosterone production, both
of which affect an increase of blood volume. - antidiuretic hormone
The detrusor muscle receives motor innervation from
nerve cells in the intermediolateral columns of gray matter, mainly from the ______________
third and also from the second and fourth sacral segments of the spinal cord (the “detrusor
center”).
The internal sphincter and base
of the bladder (trigone), consisting of smooth muscle, are
also innervated to some extent by the sympathetic fibers
of the hypogastric nerves; their receptors are mainly of
__________
alpha-adrenergic type,
The external urethral and anal sphincters are composed
of ___________ Their innervation, via
the pudendal nerves, is derived from a densely packed
group of ____________ in the
anterolateral horns of sacral segments 2, 3, and 4.
striated muscle fibers.
somatomotor neurons (nucleus of Onuf)
where is the lesion:
dyssynergia of the detrusor and external
sphincter muscles
supraspinal levels
The storage of urine and the efficient emptying of
the bladder are possible only when the spinal segments,
together with their afferent and efferent nerve fibers,
are connected with the so-called micturition centers in
the _____________
pontomesencephalic tegmentum
Increased BF in the ff brain structures during micturition
Increased blood flow was detected in the right pontine
tegmentum, periaqueductal region, hypothalamus, and
right inferior frontal cortex
The act of micturition is both reflex and voluntary.
When the normal person desires to void, there is first a
voluntary relaxation of the ___________, followed sequentially by an increased tension of the abdominal wall, a slow contraction of the _________, and an associated opening of the ________; finally, there is a relaxation of the _______
perineum
detrusor
internal sphincter
external sphincter
The
coordination of detrusor and external sphincteric function
depends mainly on the descending pathway from the
posited centers in the ______
dorsolateral pontine tegmentum.
stimulates smooth muscle and
the latter also regulates mucosal secretion and blood
flow.
myenteric (or Auerbach) plexus
changing from the recumbent to the standing
position, a fall of more than _______ systolic and _________diastolic is abnormal
30 mm Hg
15 mm Hg
the arm on which the cuff is
placed must be held ________ when standing, so that
the decline in arm pressure will not be obscured by the
added hydrostatic pressure
horizontally
Moreover, blood pressure is most informative
if measured immediately after ________ and again at
approximately ________
standing
1 and 3 min
The expected response in BP testing is a
momentary and slight ________ in pressure that is usually not detected with a manual blood pressure cuff, followed by a ________________, and then a slow recovery during the ________
increase
slight drop within seconds of standing
first minute
The failure of the heart rate to rise in response to the drop in blood pressure with sta nding is the simplest bedside indicator of ________
vagal nerve dysfunction
Neurally mediated syncope may
show one of three initial patterns with testing on a tilt
table:
- paroxysmal vasodepressor response alone,
- combined bradycardic and hypotensive response
- bradycardia
The ratio of R-R intervals in the electrocardiogram
(ECG), corresponding to the ____________is an even more sensitive measure of the integrity of vagal inhibition of the sinus node.
A ratio in adults under age 60 of less than ________ is
usually abnormal, indicating a loss of vagal tone and the
normal ratio is progressively higher for younger ages
thirtieth and fifteenth beats (the 30:15 ratio),
1 .07
more accurate test of vagal function is the measurement
of the ratio of the longest R-R interval during forceful slow expiration (standardized as constant blowing
at a pressure of 40 mm Hg for 10 s) to the shortest R-R
interval during inspiration, which allows the derivation
of an __________
expiration-inspiration (E:I) ratio.
Failure of the heart rate to increase during the positive intrathoracic pressure phase of the Valsalva maneuver points to_________ and failure of the rate to slow during the period of blood pressure overshoot points to a __________
sympathetic dysfunction,
parasympathetic disturbance.
_____________ referring to the maximum
heart rate generated by the maneuver to the lowest heart
rate within 30 s of that peak, is another often-used measure in comprehensive autonomic testin
The Valsalva ratio,
Measurement of the _________ is a rough but
useful index of vasomotor function
skin temperature
Vasomotor paralysis results in __________ and a __________ in skin temperature;
vasodilatation of skin vessels
rise
Vasoconstrictor tone may also be tested by measuring the
______________ at a distant site before and
after immersing one or both hands in cold water
reduction in skin temperature
Vasoconstriction induces an elevation of the blood
pressure. This is the basis of the ________
cold pressor test.
In normal persons, immersing one hand in ice water for 1 to 5 min raises the systolic pressure by _________ and the diastolic pressure by_______
15 to 20 mm Hg
10 to 15 mm Hg.
sustained isometric contraction of a group of muscles (e.g., those of the forearm in handgrip) for 5 min normally
increases the heart rate and the systolic and diastolic pressures by at least _____
15 mm Hg
The stress involved in doing__________ in noisy and distracting surroundings will also stimulate a mild but
measurable increase in pulse rate and blood pressure
mental arithmetic
If the response to the Valsalva maneuver is abnormal
and the response to the cold pressor test is normal, the
lesion is probably in the ___________
baroreceptors or their afferent
nerves;
A
failure of the heart rate and blood pressure to rise during
mental arithmetic coupled with an abnormal Valsalva
maneuver suggests a defect in the _________
central or peripheral
efferent sympathetic pathways.
The integrity of ____________ can be
assessed further by tests of sudomotor activity
sympathetic efferent pathways
The most rudimentary tests involve ________
after it is absorbed by small squares of filter paper.
Also, powdered charcoal dusted on the skin will cling to moist areas and not to dry ones.
weighing sweat
In the ______________ a set
of electrodes placed on the skin measures the resistance
to the passage of a weak current through the skin; in all
likelihood, the change in electrical potential is the result
of an ionic current within the sweat glands, not simply
an increase in sweating that lowers skin resistance
sympathetic or galvanic skin-resistance test,
the galvanic skin response is subject
to _________ with repeated stimuli and will show
no response if there is a ________
habituation
sensory neuropathy
The starch
iodine test or use of a color indicator such as _______
(gray when dry, purple when wet) and the more recently
introduced __________are other acceptable procedures to delineate peripheral nerve or spinal cord lesions based on the loss of sympathetic innervation.
they are termed _______
quinizarin
plastic or silicone method
“thermoregulatory sweat testing
It is essentially a
test of distal sympathetic axonal integrity utilizing the
local axon reflex.
QSART
quantitative sudomotor axon reflex test
abnormalities in QSART
patterns of absent or delayed sweating that
signify postganglionic sympathetic failure in small-fiber
neuropathies and excessive sweating or reduced latency
in response, as is seen in reflex sympathetic dystrophy
Normal for Schirmer test
After 5 min, the moistened area extends for a length
of approximately 15 mm in normal persons
Bladder function i s best assessed b y the ____________ which measures intravesicular pressure as a function of the volume of saline solution permitted to flow by gravity into the bladder.
cystometrogram,
Nocturnal penile tumescence is recorded in some
sleep laboratories and may be used as an ancillary test of
____________
sacral autonomic (parasympathetic) innervation.
the phenomenon
of denervation hypersensitivity, in which an effector
organ, 2 to 3 wk after denervation, becomes hypersensitive
to its particular neurotransmitter substance and
related drugs.
“Cannon law,
Relatively recently, the weak direct sympathetic agonist
_________ has been used most widely to demonstrate
that miosis is due to sympathetic denervation
of the pupil
apraclonidine
aproclonidine test results
A positive test, reversal of miosis, depends on the
denervation hypersensitivity that develops after several
days or more of the presence of the Horner syndrome.
what is the hydroxyamphetamine test for the sympathetic denervation of the pupil?
its effect depends on the presence
of existing norepinephrine in the end terminals of the
nerves that innervate the iris. Failure to dilate indicates a
postganglionic lesion.
results of cocaine test for sympa denervation
A normal response to cocaine consists of
pupillary dilatation. In sympathetic denervation caused
by lesions of the post- or preganglionic fibers, no change
in pupillary size occurs because no transmitter substance
the topical application
into the conjunctival sac of a 4 to 10 percent cocaine
solution that potentiates the effects of_________by preventing its reuptake.
NE
In the cutaneous flare response:
The wheal and the deeply colored red areola are
caused by the _____________
in response to local injury, while the flare depends on
the integrity of the _________
direct action of histamine on blood vessels
axon reflex
In the cutaneous flare response:
This axon reflex is mediated
by antidromic stimulation of _____________
that results in the release by the same fibers of various
vasoactive substances such as bradykinin and substance
P.
small sensory C fibers
In patients with familial dysautonomia, the infusion
of NE produces____________, probably
representing an exaggerated response to endogenous NE.
erythematous blotching of the skin, like
that which may occur under emotional stress
The integrity of autonomic innervation of the heart
can be evaluated by the intramuscular injection of __________________ while the heart rate is
monitored.
atropine,
ephedrine, or neostigmine
Normally, the intramuscular injection of
0.8 mg of atropine causes ____________ as a result of a
parasympathetic block and a withdrawal of vagal tone
tachycardia
Normally, when a person changes from a recumbent to a
standing position, the serum NE level rises__________________
two- or threefold.
The ___________ enzyme is deficient
in patients with a rare form of sympathetic dysautonomia
dopamine /3-hydroxylase
In acute autonomic paralysis, the sympathetic and parasympathetic parts of the autonomic
nervous system are affected, mainly at the_______ level
postganglionic
level.
In this syndrome, unlike the common
forms of orthostatic hypotension (see later), the fall in
blood pressure is accompanied by tachycardia
sympathotonic orthostatic hypotension
Individual cases
of POTS have been associated with mutations or epigenetic
alterations in the __________
norepinephrine transporter gene
Idiopathic Orthostatic Hypotension; Pure
Auto n o m i c Fa i l u re is caused by:
- degenerative disease of middle and
late adult life, - multiple system atrophy
In the_____________of autonomic failure,
plasma levels of NE are subnormal while the patient
is recumbent because of failure of the damaged nerve
terminals to synthesize or release catecholarnines
postganglionic type
In all forms of multiple system atrophy; the autonomic
failure is attributable to degeneration of _________
lateral
horn cells of the thoracic cord
Treatment of orthostatic hypotension consists of having
the patient sleep with the head of the bed elevated,
administering the peripherally acting alpha agonist, ______________ starting at 2.5 mg q4h, slowly raising the dose to 5 mg q4h, taking the last dose before about 7 P.M . to void supine hypertension while asleep
midodrine
alternative tx for orthostatic hypotension
mineralocorticoid fludrocortisone acetate
(Florinef) 0.1 mg twice daily
An additional feature of the acute dysautonomias
is a tendency to develop hyponatremia, presumably
as a result of dysfunction of afferent fibers from venous,
right atrial, and aortic arch volume receptors; this elicits
a release of___________
antidiuretic hormone arginine vasopressin
(AVP) .
Pathologic features of Fa m i l i a l Auto n o m i c Neuropathy i n I nfa nts a n d C h i l d ren ( R i l ey-Day Synd rome)
The main
pathologic feature is a deficiency of neurons in the superior
cervical ganglia and in the lateral horns of the spinal
cord.
In ( R i l ey-Day Synd rome), It is now known that this defect is the result of a mutation in the gene ______that codes for a protein________ that is currently considered to be associated with transcription regulation
(IKBKAP)
IKAP
Autonomic symptoms are also a prominent feature
of the small-fiber neuropathy of_____________________ as a result of the accumulation
of ceramide in hypothalamic and intermediolateral column
neurons
Fabry disease (alphagalactosidase deficiency)
Interruption of postganglionic sympathetic fibers at any
point along the internal carotid arteries or a lesion of the
superior cervical ganglion results in miosis, drooping of
the eyelid, and abolition of sweating over one side of the
face; this constellation is the Homer, or more properly,
Bernard-Homer syndrome
A lesion of the stellate ganglion, e.g., compression
by a tumor arising from the superior sulcus of the lung
(Pancoast tumor), produces the interesting combination
of a _________ and _______
Homer syndrome and paralysis of sympathetic
reflexes in the limb (the hand and arm are dry and
warm)
The combination of segmental anhidrosis and an
Adie pupil is sometimes referred to as the ________
it may be abrupt in onset and idiopathic, or it may follow
a viral infection.
Ross syndrome;
Lesions of the _________ segments of the spinal cord, if
complete, will interrupt suprasegmental control of both
the sympathetic and sacral parasympathetic nervous systems.
C4 or C5
What is this state called?
The autonomic changes include
hypotension, loss of sweating and piloerection, paralytic
ileus and gastric atony, and paralysis of the bladder. The
flare component of the axon reflex may be lost. Plasma
epinephrine and NE are reduced
spinal shock
Nt associated with spinal shock
catecholarnines, enkephalins, endorphins, substance P, and 5-hydroxytryptarnine
_________ mitigates some of the aspects of spinal
shock; this may be, at least in part, the result of release
of preformed endogenous opioids from the distal axons
that are separated from their cells of origin in the periaqueductal
gray region.
Naloxone
With __________, there is a loss of the sympathetically mediated cardiovascular
changes in response to stimuli reaching the
medulla
cervical cord
lesions
BP compensation in tetraplegic patients
a fall in blood pressure is
not compensated by sympathetic vasoconstriction
After a time, the tetraplegic patient may develop a
mass reflex in which flexor spasms of the legs and involuntary
emptying of the bladder are associated with a
marked rise in blood pressure, bradycardia, and sweating
and pilomotor reactions in parts below the cervical
segments___________
(autonomic dysreflexia).
Several toxic and pharmacologic agents such as _____
and _________ are capable of producing
abrupt overactivity of the sympathetic and parasympathetic nervous systems-severe hypertension and mydriasis coupled with signs of CNS excitation-sometimes including seizures
cocaine and phenylpropanolamine
_________ in excessive
doses are also known to produce autonomic effects, but in this case cholinergic blockade leads to dryness of the
mouth, flushing, absent sweating, and mydriasis.
Tricyclic antidepressants
Poisoning with organophosphate
insecticides (e.g., Parathion), which have anticholinesterase
effects, causes a combination of ______ and _____
parasympathetic overactivity
and motor paralysis
The exaggerated sympathetic state that accompanies
tetanus-manifest by diaphoresis, mydriasis, and labile
or sustained hypertension-has been attributed to circulating
catecholarnines
Regarding the acute sympathetic reaction, experimental
evidence suggests that nuclei in the caudal ________ can precipitate severe hypertensive
reactions
medullary
reticular formation (reticularis gigantocellularis
and parvocellularis)
mechanisms of hypersympathetic state in TBI and ICH
- brainstem-mediated vasopressor reaction
- outpouring of adrenal catecholarnines at the time of the ictus
- “diencephalic autonomic seizures”
A role has also been inferred for the ____________pressor centers in the maintenance of essential hypertension .
ventrolateral
medullary
Most profound effect of TL Sympathectomy
abnormality is an impairment of vasomotor reflexes
This disorder, characterized b y episodic, painful blanching
of the fingers and presumably caused by digital
artery spasm,
Ray n a u d Syn d ro m e
sequence of color change in Raynaud
The appearance is of a triphasic sequence of color change
of pallor, cyanosis, and subsequent rubor of the affected
fingers or toes, but about one-third of such patients have
no cyanosis
