Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
42 Cards in this Set
- Front
- Back
|
What part(s) of an Action Potential are negative feed back loops? |
repolarization and hyperpolarization |
|
|
What part of an Action Potential is a positive feed back loop? |
depolarization |
|
|
What is the mechanism of depolarization? |
high voltage -> high sodium conductance -> high sodium current |
|
|
What is the mechanism of repolarization? |
high voltage -> high K conductance -> high K current -> low voltage |
|
|
What is the mechanism for hyper polarization? |
low voltage -> low K conductance -> low K current -> high voltage |
|
|
What does E not quite reach ENa at the peak of the AP or Ek at maximum hyperpolarization? |
At the peak there is permeability to both ions, so ENa never reaches E. Potassium gates close slowly so thats why Ek is never at maximum hyper polarization |
|
|
Why does the peak depolarization occur before gNa reaches its peak value? Why does the maximum hyper polarization occur after the peak of gK? |
Because potassium gates are being opened right after peak depolarization. The potassium gates are still slightly open and slowly flowing. |
|
|
Why des the peak of INa occur after both the peak depolarization and the peak of gNa? Why does Ik peak before both gK and the maximum hyper polarization? |
The gradient creates a strong driving force, even though not all of the channels are open. |
|
|
Explain the notch of INa |
The gradient was decreasing faster than the conductance could increase. |
|
|
What is the depolarization phase of the action potential steeper than the depolarization phase? |
channels are opened quickly, so the action potential can be maintained
|
|
|
Why do gNa and gK have different decay patterns? |
Sodium channels open and close quickly whereas potassium channels close slowly so they have a less prominent peak. |
|
|
Is the membrane potential at the point of threshold the same value under different experimental conditions? |
Yes, because the sodium gates are voltage gated so the threshold will remain the same |
|
|
Given the ionic current response of a single ion channel, how do you explain the "smooth, rounded" shape of the action potential? |
The two ions give it a gradual rounded shape, but if it were 1 ion channel, it'd be pointed
|
|
|
What are some factors other than sex that contribute to observed differences in clench strength? |
Age, Muscle Fatigue, Genetics, Physical Build |
|
|
Why would there be a difference in tonus between the muscle clenches and why? |
Yes, because the dominant hand was able to clench stronger meaning the tonus will be stronger between the clenches. The other hand had less strength to clench so the tonus will be lower |
|
|
Does the subject's gender influences your expectations? |
Males can clench harder because they produce testosterone which produces proteins that make muscles stronger |
|
|
Explain the source of signals detected by the EMG electrodes? |
Action Potentials (representing muscle contractions) being propagated along the muscle fibers were the source of the detected signals |
|
|
What does "motor unit recruitment" mean? |
It is the measure of the amount of motor neurons activated in a particular muscle. The higher the unit recruitment, the stronger muscle contraction |
|
|
Define skeletal muscle tonus |
It is the continous, passive, partial contraction in between clenches |
|
|
What is electromyography |
A technique used to record and evaluate electrical activity produced by a skeletal muscle
|
|
|
What is the difference between integrated and raw EMG? |
Raw EMG shows electrical activity of an action potential (show depolarization + and depolarization-) Integrated EMG show total electrical activity (absolute value) |
|
|
What are contractile proteins? |
proteins that generate force during a muscle contraction |
|
|
What are regulatory proteins? |
Proteins that help turn on and off the muscle contraction |
|
|
What is conductance? |
the ability for electricity to flow on a given path (ease of flow) |
|
|
What is current? |
Flow of charged particles through a medium |
|
|
What is the Nerst Equation? |
EB-EA= 61/z log [ion]out/[ion]in |
|
|
What is the difference between absolute and relative refractory period? |
Threshold stimulus strength required to elicit an action potential during the relative refractory period. No stimulus, no matter how strong, will bring the neuron to threshold during the absolute refractory period. |
|
|
What are the 3 steps for a muscle twitch? |
latency, contraction, and relaxation |
|
|
A single muscle fiber or unit is ____________ |
ALL or NONE |
|
|
Whole muscle is NOT______________ |
ALL or NONE |
|
|
What is motor unit summation? |
the higher the number of active motor units, the higher the force generated |
|
|
What is temporal summation? |
the higher the frequency of the stimuli, the higher the force generated |
|
|
What is unfused tetanus? |
the relaxation time between successive twitches will get shorter as the strength of contraction increases |
|
|
What is fused tetanus? |
smooth, sustained muscle contraction |
|
|
what is a motor unit? |
it consists of one motor neuron and all the skeletal muscle fibers it innervates |
|
|
What is the highest percentage of muscle that can be used? |
60% |
|
|
What is Fatigue and what is it caused by? |
Fatigue is a decrease in force produced over time. It is a result of inorganic phosphate molecules blocking the binding site on actin in which ATP is not being replenished as quick as it is being used |
|
|
What are the three types of muscle fibers? |
slow oxidative (red), fast oxidative (pink), and fast glycolytic (white) |
|
|
What are the features of slow oxidative? |
-it has a lot of myoglobin which binds oxygen -it used cellular respiration (oxidative phsophorylation) -they are fatigue resistant
|
|
|
What are the features of fast oxidative? |
-has myoglobin and glycogen -uses cell respiration and glycolysis -they fatigue slowly |
|
|
What are the features of fast glycolytic? |
-they use glycolysis to make ATP -they fatigue very quicky -have a lot of glycogen
|
|
|
What is resistance? |
opposition of a substance |
