Neuromuscular Physiology Flashcards
the Motor nerves EFFERENT exit the _____-
Ventral cord
The Sensory nerves AFFERENT enter the ______
Dorsal Cord
The release of NT from all nerve terminals, including the motor nerve terminals, depends on the entry into the terminal of _____ ions
Calcium Ca++
“Calcium goes in, Neurotransmitter goes out”
_____calcemia is associated with a decrease in the amount of NT released, and _____calcemia is associated with an increase in the amount of NT released
Hypocalcemia
Hypercalcemia
____magnesemia is associated with an increase in the amount of NT released, and _____magnesemia is associated with a decrease in the amount of NT released
Hypomagnesemia
Hypermagnesemia
Calcium and magnesium are (antagonistic/agonistic) at the nerve terminal ( presynaptically)
Antagonistic
it takes ___ molecules of ACh to open the ACh-gated channel of the skeletal muscle motor end-plate
2
In addition to ACh, acetylcholinesterase also degrades ___, _____, _____, ____, and ______.
Ester LA Neostigmine Edrophonium Remifentanil Esmolol
At the neuromuscular junction, does the presynaptic action of SCh enhance or antagonize it’s postsynaptic action?
SCh, by stimulating the presynaptic nicotinic receptor, AUGMENTS the release of ACh. Since the released ACh opens channels and depolarizes the motor end plate like SCh, the presynaptic action of SCh ENHANCES its postsynaptic action.
when the channel of the motor end-plate opens ___ and ___ diffuse into the cell and ___ diffuses out.
Na+ and Ca++
K+
Metabolism is the primary route of elimination for what 4 Neuromuscular relaxants
Sch
Atricurium
Cisatracurium
Mivacurium
All besides SCh are CURIUM
Billary excretion is the primary route of elimination for what 2 Neuromuscular relaxants
Vecuronium
Rocuronium
Both CURONIUM
Renal excretion is the primary route of elimination of what 6 Neuromuscular relaxants
Pancuronium Then all of the other weird ones not in current use d-tubocurarine Metocurine Gallamine Doxacurium pipecuronium
how is Atracurium eliminated?
Ester hydrolysis (nonspecific esterases, biological elimination) and Hoffman Elimination ( pH & temp depenent degradation, chemical elimination)
How is Cisatracurium eliminated
Hoffmann elimination ONLY
non-specific esterases are NOT involved in the elimination
is ELIMINATION the same as TERMINATION OF ACTION?
Fuck no
What 2 neuromuscular relaxants produce autonomic ganlionic bockade?
d-tubocurarine and Metocurine
–block the nicotinic receptors at the autonomic ganglia–
In th future these neuromuscular relaxants are always together for a choice
which 5 neuromuscular relaxants elicit a release if histamine?
SCh Mivacurium Atracurium d-tubocurarine Metocurarine
what neuromuscular relaxants produces bradycardia? and why?
SCh
- it mimics the action of ACh and directly stimulates muscarinic receptors of the SA node
What 5 neuromuscular relaxants produce Tachycardia and why?
Atracurium, d-tubocurarine, and Metocurine -Produce reflex tachycardia
Pancuronium and Gallamine- competitively antagonize ACh, which are refered to as direct VAGOLYTIC, or more specifically ANTIMUSCARINIC actions
Which 3 neuromuscular relaxants produce significant HYPOtension
SCh
d-Tubocurarine
Metocurine
what 2 neuromuscular relaxants produce significant HYPERtension
Pancuronium
gallamine
Plasma K+ concentrations may increase by ____ in normal patients and by ____ in burn, trauma, or head injury patients following the administration of SCh
0.5 mEq/L
5-10 mEq/L
Why isn’t cardiac muscle directly involved in Malignant Hyperthermia?
Cardiac myocytes express the RyR2 isoform of the ryanodine receptor (MH targets the RyR1)
what things decrease NDMR block?
anticonvulsants (chronic use)
Thermal burn injury
(basically anything and everything else causes an increase in block)
What things decrease the DMR block?
Nondepolarizing agents (besides Panc)
MG
(basically anything else increases the block)
A phase II block will mimic the response seen in what type of blockade?
Nondepolarizing
