Action Potential
Motor neurons release _____ at the neuromuscular junction.
Acetylcholine
What is the change in electrical charges across the membrane known as?
Action potential
What neurotransmitter triggers muscle contraction?
Acetylcholine
What are the 4 stages of the cross bridge cycle?
Cross-bridge formation, the power stroke, cross-bridge detachment, and cocking myosin head
What ion is responsible for triggering threshold membrane potential?
Sodium Ions
What is a single neuron that controls one or more muscle fibers called?
A motor unit
Which ion is released from the sarcoplasmic reticulum to initiate contraction?
Calcium ions
During the second stage of the cross bridge cycle what is released?
ADP and potassium or Pi
Action potential will only be initiated if...
Neuron reaches the threshold potential.
In what period/stage are cross bridges actively forming and causing contraction?
Period of contraction (muscle twitch stage)
Which protein does calcium bind to during muscle contraction?
Troponin
What is the purpose of "The Cross Bridge Cycle"?
To allow muscle contraction
Which picture illustrates temporal summation?
The one in green.
What type of muscle fibers would a marathon runner use?
Slow oxidative
What molecule provides energy for muscle contraction?
ATP
What does troponin bind to in the cross-bridge cycle?
Calcium
What are the opposite roles of voltage-gated sodium channels and voltage-gated potassium channels?
Delay of potassium channels opening allows potassium ions to leave the cell and repolarize membrane. While opening of sodium channels allows for influx of sodium ions to transmit an action potential after membrane has been depolarized.
Which processes supply energy for muscle contraction?
Glycolysis or oxidative phosphorylation
What process allows myosin to bind to actin during contraction?
Cross-bridge formation
What is the role of calcium in muscle contraction?
- Troponin to bind to calcium
- Troponin binds to tropomyosin
- Tropomyosin blocks the myosin binding sites on actin
- All of that starts the cross bridge cycle.