Term
What is the resting membrane potential in large myelinated peripheral nerves and skeletal muscles?
A. -50 mV
B. -90 mV
C. -110 mV
D. -160 mV |
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Definition
B. -90 mV
determined mainly by the potential of K+ (-94mV)
K 100x more permeable than Na
at soma: -65mV
small nerve fibers: -55mV
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Term
What is threshold for initiation of an action potential?
A. +65 mV
B. -65 mV
C. +90 mV
D. -90 mV |
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Definition
-65mV
AP: Na permeability increases. Then Na channels closes and K channels open
AP starts at axon hillock |
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Term
Velocity of the AP increases with:
A. increased transmembrane resistance, increased internal resistance, decreased membrane capacitance
B. decreased transmembrane resistance, decreased internal resistance, decreased membrane capacitance
C. increased transmembrane resistance, decreasd internal resistance, decreased membrane capacitance
D. increased transmembrane resistance, decreased internal resistance, decreased membrane capacitance |
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Definition
C. increased transmembrane resistance, decreasd internal resistance, decreased membrane capacitance
myelin increases transmembrane resistance and decreased membrane capacitance |
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Term
Which toxin blocks Na channels
A. tetrodotoxin
B. TEA
C. glycine
D. aminoglycosides
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Definition
tetrodotoxin: blocks Na channels
TEA blocks voltage gated K channels
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Term
How many quantum are released to cause a miniature end plate potential?
A. 1
B. 2
C. 3
D. 4 |
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Definition
A. 1 quantum
each presynaptic vesicle contains 10,000 molecules of acetylcholine or 1 quantum
1 quantum causes a miniature end plate potential |
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Term
Which of the nicotinic receptor binding sites binds Ach?
A. alpha
B. beta
C. Delta
D. gamma |
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Definition
A. alpha
nicotinic receptor: two alpha, one beta, delta, gamma
alpha subunit: 4 hydrophobic transmembrane proteins
stimulation of receptor: fast EPSP
block: hexamethonium
nicotinic receptor at NMJ only has two subunits |
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Term
Which of the GABA receptors binds benzos?
A. type A
B. type B
C. Type C
D. Type D
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Definition
A. type A
type A: binds benzos barbiturates
type B: baclofen
GABA blocked by picrotoxin
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Term
What is the coagonist for the NMDA receptor?
A. Mg
B. glycine
C. glutamate
D. acho |
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Definition
B. glycine needed as coagonist
when receptor depolarized, MG driven out and channel opens
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Term
Which type of synapse is unidirectional?
A. chemical
B. Electrical |
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Definition
A. chemical: unidirectional
Electrical: bidirectional |
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Term
which NT is produced in the presynaptic terminal
A. acetylcholine
B. Norepi
C. Dopamine
D. Glutamate |
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Definition
A. acetylcholine
only NT to be made in presynaptic termial
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Term
Hexamethonium blocks what receptor
A. muscarinic
B. nicotinic
C. adrenergic
D. dopaminergic |
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Definition
A. nicotinic
blocks in a depolarizing fashion that cannot be refersed by anticholinesterase
muscarinic receptors are blocked by pertussis toxin |
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Term
Match the following
A. Meissner corpuscles 1. touch pressure; slow; superficial
B. Merkel disk 2. touch; rapid; superficial
C. Pacinian corpuscle 3. vibration; rapid; superficial/deep
D. Ruffini End organ 4. touch,slow; deep |
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Definition
A. 2. Meissner: touch, rapid, superficially in dermal papillae of non hairy skin; small receptor fields; transmit via large fibers
B. 1. Merkel: touch/pressure; slow; small field; superficial in dermal papillae; group together
C. 3. pacinian: vibration; rapid; superficial and deep
D. 4. Ruffini; heavy touch; slow; deep; large fields |
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Term
Are C fibers myelinated
A. yes
B. no
C. maybe |
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Definition
B. No
pretty much every thing else is |
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Term
| What is the somatotopic organization of the dorsal column system in the spinal cord, brain stem and sensory cortex? |
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Definition
Spinal cord: legs medial (f. gracilis) and upper extremities lateral (f. cuneatus)
Brainstem: lower extremities are lateral
Cortex: lower extremities medial again |
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Term
| Which autonomic system is associated with more vague visceral symptoms and why? |
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Definition
Sympathetic
Neurons synapse in the sympathetic chain and then travel a long way to end organs, leading to more vague pain vs. the PSNS where the nerves synapse closer to the end organs |
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Term
| What are the 7 orders of the neurons in the auditory pathway? |
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Definition
First order: spiral ganglion
Second order: dorsal and ventral cochlear nuclei in medulla
3rd: contralateral superior olivary nucleus
4th: lateral lemniscus
5th: inferior colliculus
6th: medial geniculate body
7th: auditory cortex |
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Term
What toxin blocks renshaw cells in the spinal cord
A. tryptophan
B. tetanus
C. scorpion toxin
D. botox |
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Definition
B. tetanus
renshaw cells located in anterior horn
alpha motor neuron sends a branch to renshaw cells which uses glycine to inhibit alpha motor neurons and inhibit antagonizing inhibitors
strychnine also blocks
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Term
Match the NT and where there are found in large quantities
A. NE
B. Serotonin
C. Dopamine
D. Acetylcholine
1. raphe
2. locus ceruleus
3. basal nucleus of meynert
4. basal ganglia and SN |
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Definition
A. 2 NE: (+) locus ceruleus
B. 1. serotonin: (-) raphe nucleus
C. 4. dopamine. (+ or -) basal ganglia and SN
D. 3. Acho. (+) basal nucleus of meynert |
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Term
A lesion in which of the following areas results in a reduction of REM sleep:
A. substantia negra
B. raphe nucleus
C. locus cureulus
D. sensory cortex |
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Definition
C. locus ceruleus
decreases REM sleep because it activates certain cortical areas during REM sleep without causing wakefulness |
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Term
A patient has an EEG while sleeping that shows delta waves. What stage of sleep is this
A. 1
B. 2
C. 3
D. 4
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Definition
D. 4, maybe 3 too
Beta: active
Alpha: awake/quiet: go away in stage 1 sleep
sleep spindles/k complexes: stage 2
theta: can see in state 2/3
stage 3/4: delta |
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Term
contraction of the bladder detrusor is controlled by which system
A. PSNS
B. SNS
and it results in
A. bladder contraction
B. bladder relaxation and voiding
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Definition
A, B
detrusor contraction is PSNS and causes bladder to empty
External sphincter: pudendal nerve
SNS: keeps bladder from voiding (a1 and B)
So cholinergics help with bladder emptying
detrusor instability is made worse by cholinergics because you're just increasing cholinergic tone, which is part of the problem (drugs to use: oxybutynin)
Conversely, inability to void is due to too much SNS so you use a1 antagonists (terazosin) to help void |
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Term
which of the following anticholinesterases is irrefersible
A. neostigmine
B. organophosphates
C. pyridostigmine
D. physostigmine |
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Definition
B. organophosphates
Think of farm kids playing in the barn and then all of then start salivating a lot |
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Term
the micturation reflex is located where?
A. midbrain
B. pons
C. medulla
D. spinal cord |
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Definition
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