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32 Cards in this Set
- Front
- Back
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Which kind of graded potential is always instigated by GLUTAMATE?
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EPSP
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Which kind of graded potential is always instigated by GLYCINE?
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IPSP
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What is the formula for CAPACITANCE?
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C = Q / V;
ie. Capacitance = Charge / Voltage |
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What is Ohm's Law?
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V = I * R
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When does the membrane potential follow Ohm's Law?
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Once the capacitance of the membrane has been overcomed.
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What is the range of RMPs for typical nerve/muscle cells?
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-60 to -90 mV
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What are the extra/intracellular concentrations of Na+ in mmol/L?
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Extra - 150 mmol/L
Intra - 15 mmol/L |
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What are the extra/intracellular concentrations of K+ in mmol/L, and what is its relative permeability as compared to Na+?
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Extra - 5 mmol/L
Intra - 150 mmol/L Relative permeability - 50-75 times that of Na+ |
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What are the extra/intracellular concentrations of A- in mmol/L, and what is its relative permeability as compared to Na+?
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Extra - 0 mmol/L
Intra - 65 mmol/L Relative permeability - 0 |
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What would occur if intravenous KCl was injected?
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Heart would briefly depolarize and then stop beating due to inactivation of cardiac Na channels.
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How do local anaesthetics work?
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Block Na channels in sensory nervesto prevent AP generation.
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What occurs during paralytic shellfish poisoning?
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Saxitoxin blocks Na channels.
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What characterizes group A fibers? (myelination, diameter, conduction velocity)?
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Myelinated, 1-20 um, 5-100 m/s
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What characterizes group B fibers? (myelination, diameter, conduction velocity)?
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Myelinated, 1-3 um, 3-14 m/s
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What characterizes group C fibers? (myelination, diameter, conduction velocity)?
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Unmyelinated, <1 um, <3 m/s
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What does myelination accomplish electronically for a neuron?
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Reduces leakage (effectively increasing voltage)
Increases thickness (effectively reducing capacitance) |
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What occurs in demyelinating disorders?
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Membrane capacitance is increased; AP progresses more slowly, ephaptic transmission
Motor: muscle paralysis/weakness |
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What is ephaptic transmission?
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When a neuron is incorrectly excited by APs in nearby regions of same trunk.
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What is multiple sclerosis?
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Demyelinating lesions in the CNS. Motor, vision, bladder disturbance.
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What is Guillain-Barre Syndrome?
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Peripheral nerve demyelination. Motor weakness of fast onset, parasthesias, pain. RESPIRATORY MUSCLES fail.
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Give 3 examples of chemical transmitters?
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Substance P, Vasoactive Intestinal Polypeptide (VIP), opioid peptides
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List the CHOLINE neurotransmitters and their function
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Acetylcholine (Ach) - usually excitation
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List the AMINE neurotransmitters and their function
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Epinephrine (E) - Either
Norepinephrine (NE) - Either Serotonin (5-hydroxy-tryptamine, 5-HT) - Either Dopamine (DA) - mainly INHIBITION Histamine - Either |
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List the AMINO ACID neurotransmitters and their function
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Gamma-amino-butyric acid (GABA) - INHIBITION: BRAIN
Glycine (GLY) - INHIBITION: SPINAL CORD L-Glutamate (GLU) - EXCITATION = MSG; brian & spinal cord L-Aspartic acid (ASP) - EXCITATION |
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What are Ia fibers?
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Muscle spindle primary endings
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What are Ib fibers?
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Golgi tendon organs
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What are A alpha neurons?
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Extrafusal muscle efferents
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What are group II fibers?
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ENCAPSULATED endings: Meissener, Merkel
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What are A beta motor neurons?
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SECONDARY muscle spindle endings. Same structure as group II fibers.
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What are gamma motor neurons?
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Efferents to INTRAFUSAL muscle fibers
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What are group III/delta fibers?
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Sharp pain, cold, preganglionic autonomic efferents - B fibers
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What are group IV/C fibers?
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UNMYELINATED. Dull, chronic pain (most nociceptors), warmth, postganglionic autonomic efferents
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