ANS Flashcards
ANS is divided into two parts
sympathetic & parasympathetic
- prepare the body for emergency by increasing heart rate, constricting peripheral blood vessels, increasing blood supply to muscles, and increasing blood pressure
- redistributes blood to organs that need high performance in emergency situations
sympathetic system
sympathetic system originate in the lateral gray columns of the spinal cord
Efferent fibers
leave the cord in the anterior root and pass via the white rami communicantes to the paravertebral ganglia of the sympathetic trunk
Myelinated axons
Once these presynaptic fibers reach the sympathetic trunks, they are distributed as follows:
- Synapse with a postsynaptic sympathetic neuron in the ganglion
- Travel superiorly or inferiorly to synapse at
a different level of the sympathetic trunk. For instance, T1 fibers must travel superiorly to the superior cervical ganglion - Pass through the ganglia without synapsing, as the greater, lesser, or least splanchnic nerve, to synapse in a prevertebral sympathetic ganglion
from the viscera travels through the sympathetic ganglia without synapsing and ascends to higher centers
Afferent information
- conserve and restore energy
- heart rate
is slowed, pupils are constricted, peristalsis and glandular activity is increased, and the bladder walls are contracted
parasympathetic system
Efferent fibers of the parasympathetic system originate in the parasympathetic nuclei of cranial nerves ___ and the sacral spinal cord segments ___
III, VII, IX, and X; S2-S4
Presynaptic parasympathetic fibers of cranial nerves 11, VII, and IX synapse in the parasympathetic ganglia of the headβspecificallyβ___
ciliary, otic, pterygopalatine, and submandibular
from viscera travel with the cranial nerves and the pelvic splanchnic nerves
afferent fibers
has long postganglionic fibers
sympathetic system
has short fibers
parasympathetic
The preganglionic fibers in both the sympathetic and parasympathetic systems are ___, meaning they synthesize and release ACh at the synapse
cholinergic
The postganglionic fibers in the parasympathetic are also ___
cholinergic
Most postganglionic sympathetic neurons release ___
norepinephrine
fibers to sweat glands and blood vessels are ___
cholinergic
The skin of the upper eyelid receives sympathetic innervation from the ___
superior cervical ganglion
The pupil of the iris is constricted by parasympathetic from ___ and dilated by sympathetic fibers from the ___
cranial nerve Ill; superior cervical ganglion
receives parasympathetic fibers from cranial nerve VII and sympathetic vasoconstrictor fibers from the superior cervical ganglion
lacrimal gland
receive parasympathetic innervation from cranial nerve VII and sympathetic fibers from the superior cervical ganglion
submandibular & sublingual glands
receives parasympathetic fibers from cranial nerve IX and sympathetic fibers from the superior cervical ganglion
parotid gland
receives parasympathetic innervation from cranial nerve X and sympathetic fibers from the greater and
lesser splanchnic nerves
gastrointestinal tract
receive parasympathetic innervation from the pelvic splanchnic nerves and sympathetic fibers from the lumbar part of the sympathetic trunk
descending colon, sigmoid colon, and rectum
made up of the submucous plexus of Meissner and the myenteric plexus of Auerbach
enteric nervous system
indicates that the accommodation reflex for near vision is normal but that the light reflex is lost
Argyll Robertson pupil
Pain arising in the gastrointestinal tract is referred
to the ___
midline
The patient has vasodilation of the facial skin arterioles
Horner syndrome
restricted to the T1βL2 segments of the spinal cord
sympathetic outflow
Norepinephrine is secreted at the endings of the
postganglionic sympathetic fibers
The parasympathetic innervation controlling the parotid salivary gland arises from the
glossopharyngeal nerve
Effects are local and discrete due to preganglionic neurons synapsing with few postganglionic neurons
parasympathetic part of the autonomic nervous system
Anticholinesterase drugs act at synapses by
blocking the breakdown of acetylcholine
blocks the action of acetylcholine on effector sites in the parasympathetic system
Atropine
The parasympathetic outflow in the spinal cord occurs at levels
S2βS4
The afferent fibers from the bladder reach the spinal cord at the first and second lumbar segments and the second, third, and fourth sacral segments
autonomic innervation of the urinary bladder
The sympathetic nerves cause cardiac acceleration and increased force of contraction of the heart
autonomic innervation of the heart
Submandibular gland & Sublingual gland
Submandibular ganglion
Lacrimal gland & nasal glands
Pterygopalatine ganglion
Parotid gland
Otic ganglion
superior cervical ganglion
Levator palpebrae superioris (smooth muscle only)
Ciliary ganglion
Constrictor pupillae
Inferior mesenteric ganglion
Descending colon
Superior mesenteric ganglion
Vermiform appendiX
Facial nerve
Lacrimatory nucleus
Oculomotor nerve
EdingerβWestphal nucleus
Glossopharyngeal nerve
lnferior salivatory nucleus
The nerve cells and the nerve fibers in the enteric nervous system are surrounded by neuroglialike cells that closely resemble ___
astrocytes
___ of the autonomic system contains both afferent and efferent nerve fibers
parasympathetic part
concerned with the light reflex
pretectal nucleus
found in the thoracic and first and second lumbar parts of the sympathetic trunk
White rami communicantes
___ contain postganglionic sympathetic fibers
Gray rami communicantes
formed of myelinated axons
greater splanchnic nerves
___ arise from the 10th and 11th ganglia of the thoracic part of the sympathetic trunks
lesser splanchnic nerves
has great control over the ANS
hypothalamus
influence the ANS
cerebral cortex
decreased or absent light reflex and a slow or delayed pupillary contraction to near vision and a slow or delayed dilatation in the dark
adie tonic pupil syndrome
skin areas that are innervated by the same segment of the spinal cord as the painful viscus
visceral pain
of the bladder brings about contraction of the bladder wall muscle and relaxation of the sphincter vesicae
parasympathetic innervation
of the bladder in the male causes contraction of the sphincter vesicae and prevents the reflux of semen into the bladder during ejaculation
sympathetic innervation
made to contract voluntarily by the internal pudendal nerve
sphincter urethrae
innervate the blood vessels supplying the bladder wall.
sympathetic nerves
The parasympathetic part of the autonomic system brings about ___ of the coronary arteries
constriction
They are located in the intermediolateral cell column of
the thoracolumbar spinal cord at T1βL2
sympathetic preganglionic neurons
innervate all regions of the heart
Sympathetic postganglionic fibers
Stimulation of the parasympathetic innervation of the
constrictor pupillae muscles of the iris causes ___
miosis
A 50-year-old woman was diagnosed as having Raynaudβs disease. Which one of the following statements regarding this disease is correct?
periodic cyanosis of digits
A 65-year-oldman who has Alzheimerβs disease was prescribed donepezil (Aricept) in an attempt to improve his memory. Which one of the following is the most likely side effect of the drug?
Abdominal cramping and diarrhea
called the thoracolumbar division of the autonomic nervous system
sympathetic division
- located in the IML at sacral level S2βS4
- located in the brainstem
parasympathetic preganglionic neurons
craniosacral division of the autonomic nervous system
parasympathetic division
provided by the vagus and is restricted to the sinoatrial (SA) node, atria, and atrioventricular (AV) node
parasympathetic innervation
Activation of the ___ decreases automaticity in the SA node cells and, hence, decreases heart rat
parasympathetic nervous system
Activation of the ___ increases conduction through the AV node
sympathetic nervous system
decreases conduction through the AV node
parasympathetic nervous system
causes an increase in the heart rate and contractility
sympathetic stimulation
Stimulation of the ___ causes an increase in the motility of the gastrointestinal tract
parasympathetic nervous system
- The cause of ___ is not known
- cold or emotional stress precipitates vasoconstriction in the digits of the limbs; they appear cyanosed
Raynaudβs disease
used to treat this vascular disorder (raynaudβs disease)
Alpha-adrenergic receptor blockers and calcium channel blockers
Therefore, treatment with ___ will relieve, not exaggerate, the symptoms
alpha-adrenergic receptor blockers
acetylcholinesterase inhibitor that crosses the blood-brain barrier, is prescribed for the treatment of Alzheimerβs disease
donepezil