Download Skeletal Muscle Activity

Anatomy
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Date___________Hour_____
Skeletal Muscle Activity
Neuromuscular Junction
Motor Unit
Neuron
Axon
Axon Terminals
Dendrites
Muscle Fiber
Synaptic Cleft
Acetylcholine (ACh)
http://www.neuroanatomy.wisc.edu/SClinic/Weakness/Nmj.JPG
Sliding Filament Theory
1. Influx of calcium triggers the exposure of binding sites on actin.
2. Myosin binds to actin.
3. The power stroke of the cross bridge causes the sliding of thin filaments.
4. Binding of ATP causes cross bridge to disconnect from actin.
5. Hydrolysis of ATP leads to re-energizing and repositioning of the cross bridge.
6. Active transport of calcium ions into the sarcoplasmic reticulum.
Energy for Muscle Contraction
Muscles require ATP for muscle contraction. Muscles contain only 4-6 seconds worth of ATP. ATP
must continuously be regenerated. A lack of ATP such as in death leads to rigor mortis.
Three ways ATP is generated:
 Direct Phosphorylation of ADP by Creatine Phosphate

Aerobic Respiration (also called Oxidative Phosphorylation)

Anaerobic Respiration
Types of Muscle Contractions
Isotonic
Isometric