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32 Cards in this Set

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Which kind of graded potential is always instigated by GLUTAMATE?
EPSP
Which kind of graded potential is always instigated by GLYCINE?
IPSP
What is the formula for CAPACITANCE?
C = Q / V;
ie. Capacitance = Charge / Voltage
What is Ohm's Law?
V = I * R
When does the membrane potential follow Ohm's Law?
Once the capacitance of the membrane has been overcomed.
What is the range of RMPs for typical nerve/muscle cells?
-60 to -90 mV
What are the extra/intracellular concentrations of Na+ in mmol/L?
Extra - 150 mmol/L
Intra - 15 mmol/L
What are the extra/intracellular concentrations of K+ in mmol/L, and what is its relative permeability as compared to Na+?
Extra - 5 mmol/L
Intra - 150 mmol/L
Relative permeability - 50-75 times that of Na+
What are the extra/intracellular concentrations of A- in mmol/L, and what is its relative permeability as compared to Na+?
Extra - 0 mmol/L
Intra - 65 mmol/L
Relative permeability - 0
What would occur if intravenous KCl was injected?
Heart would briefly depolarize and then stop beating due to inactivation of cardiac Na channels.
How do local anaesthetics work?
Block Na channels in sensory nervesto prevent AP generation.
What occurs during paralytic shellfish poisoning?
Saxitoxin blocks Na channels.
What characterizes group A fibers? (myelination, diameter, conduction velocity)?
Myelinated, 1-20 um, 5-100 m/s
What characterizes group B fibers? (myelination, diameter, conduction velocity)?
Myelinated, 1-3 um, 3-14 m/s
What characterizes group C fibers? (myelination, diameter, conduction velocity)?
Unmyelinated, <1 um, <3 m/s
What does myelination accomplish electronically for a neuron?
Reduces leakage (effectively increasing voltage)
Increases thickness (effectively reducing capacitance)
What occurs in demyelinating disorders?
Membrane capacitance is increased; AP progresses more slowly, ephaptic transmission

Motor: muscle paralysis/weakness
What is ephaptic transmission?
When a neuron is incorrectly excited by APs in nearby regions of same trunk.
What is multiple sclerosis?
Demyelinating lesions in the CNS. Motor, vision, bladder disturbance.
What is Guillain-Barre Syndrome?
Peripheral nerve demyelination. Motor weakness of fast onset, parasthesias, pain. RESPIRATORY MUSCLES fail.
Give 3 examples of chemical transmitters?
Substance P, Vasoactive Intestinal Polypeptide (VIP), opioid peptides
List the CHOLINE neurotransmitters and their function
Acetylcholine (Ach) - usually excitation
List the AMINE neurotransmitters and their function
Epinephrine (E) - Either
Norepinephrine (NE) - Either
Serotonin (5-hydroxy-tryptamine, 5-HT) - Either
Dopamine (DA) - mainly INHIBITION
Histamine - Either
List the AMINO ACID neurotransmitters and their function
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
What are Ia fibers?
Muscle spindle primary endings
What are Ib fibers?
Golgi tendon organs
What are A alpha neurons?
Extrafusal muscle efferents
What are group II fibers?
ENCAPSULATED endings: Meissener, Merkel
What are A beta motor neurons?
SECONDARY muscle spindle endings. Same structure as group II fibers.
What are gamma motor neurons?
Efferents to INTRAFUSAL muscle fibers
What are group III/delta fibers?
Sharp pain, cold, preganglionic autonomic efferents - B fibers
What are group IV/C fibers?
UNMYELINATED. Dull, chronic pain (most nociceptors), warmth, postganglionic autonomic efferents