1. Activation of the sarcomere
Muscle contraction:
Activation of the sarcomere

3. Muscle contraction response:
Irritability-ability to receive and respond to stimulus
Contractility-ability to shorten when stimulus is receive
**skeletal muscles respond to a complex system of nerve impulses

4. Terminology:
Motor unit-consists of a motor neuron and all of its muscle fibers that it activates
Motor neuron-a nerve cell that is made up of and axon and dendrites
Axon-a long extension of a neuron that branches out to the muscles (terminal axon)
Neuromuscular junctions-junctions between terminal axons and sarcolemma of muscle
Synaptic cleft-gap between junctions and sarcolemma, filled with fluid
Neurotransmitter-nerve impulse causes a chemical release of acetylcholine into the synaptic cleft-sodium rushes in causing an electrical imbalance, this causes muscle contraction. Potassium is pumped out returning the muscle cells to their resting state

10. Muscle tetany:
Stimuli is so fast that muscle cannot relax-stays contracted

12. Muscle cramps: ATP depletion Dehydration Ion imbalance
Treatment-massage or stretch are to increase circulation