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47 Cards in this Set

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Relative to a healthy membrane phospholipid bilayer, where should you find sodium, potassium, and calcium?
sodium- outside
potassium- inside
calcium- stored/ transported in special structures: Sarcoplasmic reticulum/ T-tubules
T or F: There is a super tiny amount of calcium in the sarcoplasm.
True.
1mM vs. 0.00000001mM
Which way would calcium move faster?
0.00000001mM b/c it has a greater concentration gradiant
_______ manipulates membrane potential, so it can choose when to depolarize.
exciteable membrane
How do epithelial cells differ from neurons and myofibers?
Epithelial cells can manipulate the membrane potential.
_____ is the electric charge difference across the plasma membrane
membrane potential
We make a myofiber (muscle cell)______ by depolarizing it and causing calcium release into it.
contract
In an unstimulated cell there are more anions on the inside of the plasma membrane than on the outside thus the plasma membrane is electrically ______.
polarized
______ is a difference in electrical charge from one point to another.
voltage
______ is a shift in the electrical potential across a plasma membrane toward 0mV
depolarization
When a cell dies, it can't pump voltage, Na+, K+, Ca++, so it becomes ________.
depolarized
_____ open in response to voltage.
voltag-gated channels
_____ open in response to a chemical
Ligand-gated channels
Neurotransmitters like acetycholine are chemical ______.
ligands
______ lets muscle contract.
acetylcholine
The channel of acetylcholine only opens if _____ is present.
ligand
______ are holes between cardiac cells allowing ions to pass from cell to cell down their concentration gradient.
gap junctions
Damage to the _______ explains soreness after a race.
plasma membrane
4 additional ways besides cell death to depolarize membranes
1) voltage-gated channels
2) ligand-gated channels
3) gap junctions
4) stretch or damage plasma membrane
Nerve cell axon ending meets myofiber at a structure called the ______.
Motor end plate or synapse or neuromuscular junction (all mean relatively same thing)
_____ is the space between axon and myofiber
synaptic cleft
_____ contains/releases synaptic vesicles
axon
Vesicles contain the neurotransmitter _______
acetylcholine (ACH)
acetylcholine opens ___ channels that cause depolarization.
Na+
3 factors that limit duration of depolarization
1) voltage gated channels (Na+ & Ca++) only stay open for a few milliseonds.
2) Acetylcholinesterase degrades aceylcholine.
3) Sodium and calcium are rapidly pumped out.
Depolarization of the target cell occurs when what 3 things happen to ACH.
1)exocytosis
2)diffuses across synapse
3)binds/opens receptor (a ligand gated-Na+ channel)
_____ is the rapid fluctuation in membrane voltage at the motor end plate.
end-plate potential
One exocytosis may not release enough ACH to open enough ligand-gated channels to create enough depolarization to cause enough depolarization to open the ____________.
voltage gated channels
_____ means the same length, but generates more tension.
isometric
_____ means the same tension, but more length
isotonic
muscle is the sum of many _____
sarcomeres
____,____,&_____ have an ideal length that gives them the best contractile performance for a given stimulation. This is called the length-tension relationship.
1) muscles
2) myofibers
3) sarcomeres
Which is further away from zero and more negative, hyperpolarization or depolarization?
hyperpolarization
Which is closer to zero and less negative, hyperpolarization or depolarization?
depolarization
_____ prevent acetylcholinesterase from degraging ACH and are used for chemical warefare, cause a fatal seizure.
cholinesterase
______ allows a muscle to relax.
acetylcholinesterase
4 major phases of muscle contraction and relaxation
1) excitation
2) excitation-contraction coupling
3) contraction
4) relaxation
_____ is the process in which action potentials in the nerve fiber lead to action potentials in teh muscle fiber.
excitation
Which stage of muscle contraction contains an end plate potential?
excitation
What stage links action potentials in the muscle fiber to the release and binding of calcium ions?
excitation-contraction coupling
_____ is a quick up-&-down voltage shift from -to+to-
action potential
_____ is the stage in which the muscle fiber develops tension and may shorten.
contraction
_____ stage contains the sliding filament theory that causes a thin filament to slide over a thick filament and generate tension in the muscle.
contraction
_____ stage leads from the cessation of a nerve signal to the release of thin filaments by myosin.
relaxation
What happens if the muscle is overly contracted?
Thick filaments butt against the Z discs and the fiber can't contract very much more when stimulated.
What happens if the muscle is overly stretched?
Little overlap between thick and thin filaments that few cross-bridges can form between myosin and actin.
_______ is a stable voltage across the plasma membrane of an unstimulated cell
resting membrane potential (rmp)