Apex anesthesia: Autonomic Nervous System
___ mole (s) of ATP are able to be produced from ___ mole (s) of glucose
38 1
___ percent of NE is excreted unchanged in the urine
5%
the subtype nicotinic type N is found at these locations
ANS ganglia CNS neuromuscular junction
in NE synthesis, this enzyme converts DOPA to dopamine
DOPA decarboxylase
list the microgram per kilogram secretion of NE & EPI in the adrenal medulla at rest
EPI: 0.2 mcg/kg/min NE: 0.05 mcg/kg/min
list the excitatory subtypes of the muscarinic receptor and its' effector response list the inhibitory subtypes of the muscarinic receptor and its' effector
M1, M3, M5: stimulates phospholipase C M2, M4: inhibits adenylate cyclase
list the substances released by glomangiomas
NE serotonin & kallikrein histamine or bradykinin
explain the effect of sympathetic stimulation on the transcellular potassium shift
SNS stimulation releases glucose & potassium from hepatocytes into the systemic circulation
hypertension increases traffic to the nucleus tractus solitarius which pathway is affected
The rostral ventrolateral medulla & intermediolateral nucleus pathway is stimulated
define denervation
absence of autonomic tone to a distinct organ
the main function of an effector is to ___
activate the second messenger
signal transduction is when a cell converts ___
an extracellular signal into an intracellular response
this receptor augments NE release this receptor inhibits this action
augmentation: presynaptic beta-2 inhibition: presynaptic-alpha 2
this reflex uniquely remains intact in the denervated heart what is the rationale for this?
bainbridge SA node stretch directly increases its firing rate
stellate ganglion block is an unintended consequence of the type of block
brachial plexus block
list 3 types of environmental stimuli that can cause an extracellular signal
chemical stimuli (first messengers): neurotransmitter, hormone, drug electrical stimuli/ action potential: voltage change mechanical: pressure
muscarinic stimulation causes sphincter muscle ___ & ciliary muscle ___, leading to pupillary ___
contraction contraction miosis/ near vision
beta-2 stimulation causes ciliary muscle ___, leading to pupillary ___
contraction relaxation (far vision)
list 5 important second messengers
cyclic adenosine monophosphate (cAMP) cyclic guanosine monophosphate (cGMP) inositol triphosphate (IP3) diacylglycerol (DAG) calcium ion (Ca+2)
in NE synthesis, this enzyme converts dopamine to NE
dopamine B-hydroxylase
what is the fate of sympathetic fibers of piloerector muscles, sweat glands, & some blood vessels?
enter and exit the sympathetic chain renter the spinal nerve via the grey communicating rami reach their destination alongside somatic nerves
which drugs act directly on the SA node, and thus can be used to augment HR in the denervated heart?
epinephrine glucagon isoproterenol
T or F the stellate ganglion provides innervation to the contralateral upper extremity
false ipsilateral upper extremity
T or F in a G-protein couple receptor, the G-protein itself lies outside of the cell membrane and contains 4 subunits
false it lies inside of the cell membrane and contains 3 subunits subunits: alpha, beta, gamma
T or F acetylcholine is produced in the Golgi apparatus and released in the cytoplasm
false produced in the mitochondria
T or F sympathetic postganglionic fibers release Ach into the adrenal medulla
false there no postganglionic fibers in the adrenal medulla myelinated preganglionic fibers release Ach onto chromatin cells
T or F phosphodiesterase III inhibition is dependent on the sympathetic nervous system
false they act independently of the SNS
T or F adenylate cyclase & phospholipase C are second messengers
false they are enzymatic effectors
T or F steroids bind to intracellular receptors in the cell nucleus
false they bind to receptors in the cytoplasm thyroid hormone binds to receptors in the cell nucleus
T or F alpha-2 receptors are predominantly located in arteriole vasculature & cause vasoconstriction
false they cause vasoconstriction predominantly in venous vasculature
in the SNS, preganglionic fibers exit via the ventral root & enter the sympathetic chain through the grey communicating rami
false they exit the ventral root, & enter through the white communicating (myelinated) rami
after initial stimulation, how is glucose & potassium affected by the SNS system
glucose: decreased from insulin release by pancreatic beta cells due to SNS stimulation potassium: decreased from epinephrine binding to beta-2 receptors on skeletal muscle & erythrocytes by activating the Na+/K+ pump
these two vasodilators preserve the baroreceptor reflex
hydralazine nitroprusside
___ & ___ stimulate the chemoreceptor reflex list the presentations of this reflex
hypoxia & hypercarbia increased minute ventilation & SNS tone
list the key integration of ANS visceral reflex arcs for homeostasis list the 5 major components of ANS visceral reflex arcs for homeostasis
integration: renin-angiotensin aldosterone axis, ADH regulation, mineralocorticoids, glucocorticoids, & insulin components: sensor, afferent pathway, control center, efferent pathway, effector organ
the cushing reflex is an indication of ___ list the presentations of this reflex
intracranial hypertension hypertension, bradycardia, & irregular respirations
in a denervated heart, the heart rate is determined by the ___
intrinsic rate of the SA node
the 3 categories of membrane-bound receptors include ___ list an example of each
ion channel receptor (neuronal sodium channels) G-protein coupled receptor (M-2 receptor in SA node) enzyme-linked/ ligand receptor (skeletal muscle insulin receptors)
this volatile anesthetic impairs the baroreceptor the least what is the rationale behind this?
isoflurane mild beta-1 agonistic properties
Shy-Drager syndrome (multiple system atrophy) causes denervation of these structures
locus coeruleus intermediolateral column of spinal cord peripheral autonomic nerves
this mineral is an antagonist of calcium at cholinergic presynaptic terminals
magnesium
at which location in the CNS does alpha receptors cause a decrease in SNS tone, increase in PNS tone, sedation/ hypnosis, & analgesia
medulla vagus nerve locus coeruleus dorsal horn of the spinal cord
the celiac reflex is due to ___ list the presentations of this reflex
mesenteric/ abdominal traction bradycardia & hypotension
extraneuronal tissues metabolize NE & EPI through this mechanism
metabolized by monoamine oxidase (MAO) & catechol-O-methyltransferase (CMOT)
state the function of phosphodiesterase III
metabolizes cAMP to AMP, temporarily turning off cellular function
vanillylmandelic acid (VMA) is the end product of NE & EPI metabolism what is the chemical name of this compound
methoxy-4-hydroxymandelic acid
Alpha-1 stimulation causes radial muscle contraction, leading to pupillary ___
mydriasis (dilation)
explain the afferent innervation of the carotid sinus
nerves of herring & the glossopharyngeal nerve (CN-IX) carry afferent impulses to the tractus solitarius in the medulla
A glomangioma (gloms tumor) originates from ___ they grow in these tissues
neural crest cells carotid artery, aorta, glossopharyngeal nerve, & middle ear
list 2 nonselective and 2 alpha-1 selective alpha blockers
nonselective: phenoxybenzamine & phentolamine alpha-1 selective: doxazosin & prazosin
when tyrosine is unable to be obtained from the diet, this amino acid is converted to tyrosine
phenylalanine
this enzyme converts NE to EPI where does this predominantly occur?
phenylethanolamine-N-methyltransferase adrenal medulla
which enzyme to glomangioma tumors lack? which drug treats the s/sx of these tumors?
phenylethanolamine-N-methyltransferase ocreotide
an elevated VMA in the urine suggests ___ what is an important anesthetic consideration for these patients? why is this
pheochromocytoma **MUST ALPHA BLOCK BEFORE BETA BLOCK** beta blockade inhibits skeletal muscle vasodilation (B-2), increases SVR, & reduces ionotropy (B-1)
the preganglionic nerve fibers of the ANS are of this type postganglionic nerve fibers are of this type
preganglionic: lightly myelinated B-fibers postganglionic: nonmyelinated C fibers
list the symptoms of Horner's syndrome
ptosis anhidrosis miosis enopthalmos
80% of NE released is metabolized through this mechanism
reuptake
these three structures in the control center of ANS visceral reflex arc for homeostasis reflex most of the afferent sensory information
spinal cord brainstem (midbrain, pons, medulla) hypothalamus
list the different G stimulatory & G inhibitory proteins
stimulatory: Gs & Gq inhibitory: Gi
list 6 sympathetic ganglia that lie outside of the sympathetic chain
superior & middle cervical ganglion stellate ganglion celiac ganglion superior & inferior mesenteric ganglion
in the sympathetic nervous system, postganglionic fibers release acetylcholine to muscarinic receptors at these locations
sweat glands piloerector muscles some vessels
in the SNS, list the possible pathways of a sympathetic fiber once it's inside the sympathetic chain
synapses & exits at the same level travels up or down & synapses at a higher or lower level before exiting bypasses the chain & synapses at a collateral ganglion
when a G-protein is activated, the ___ subunit disassociates & subsequently turns an effector on or off
the alpha subunit when it unbinds, it rejoins the beta and gamma subunits
explain the afferent innervation of the transverse aortic arch
the vagus nerve (CN-X) carry afferent impulses to the tractus solitarius
name the prototypical PDE III inhibitor in which situations is this class of drugs useful?
theophylline beta-blocker induced cardiac depression acute heart failure catecholamine tachyphylaxis desirable increased ionotropy & reduced afterload
T or F the second messenger system allows for signal amplification
true
T or F the intracellular response to a second messenger is tissue specific
true ex: cAMP causes different effects in different cell types
The rate limiting step of NE synthesis is when ___ inhibits the conversion of ___ to ___
tyrosine hydroxylase tyrosine to DOPA
list the 4 key functions of the vasomotor center
vasoconstriction cardiac stimulation vasodilation cardiac inhibition