Muscles
Submitted by David Wheeler on Sat, 02/20/2010 - 20:22
- Skeletal Muscle
- Cardiac Muscle
- Smooth Muscle
- Skeletal (Striated Muscle)
- Structure
- Tendon - attachment to bone
- Extrafusal Muscle Fibers - major part of muscle which provides the force
- Bundle of Fibers
- myofibril
- Actin (fixed)
- Myosin (free-floating) - cross bridges
- myofibril
- Bundle of Fibers
- Intrafusal Muscle Fibers (inside the muscle spindles) - sensory feedback
- Neurons
- Ventral Horn of Spinal Cord
- alpha motor neuron -> extrafusal muscle fiber
- gamma motor neuron -> muscle spindles
- Neuromuscular Junction
- Presynaptic
- Alpha motor neuron
- Acetylcholine
- Postsynaptic
- Motor Endplates
- Endplate Potentials
- Travels along entire myofibril
- In the Myofibril
- Calcium released from storage vessicles
- Calcium causes extraction of energy from ATP
- Myosin heads attach to Actin, bend, move Actin, then release and return to relaxed state
- Myosin heads pull in toward center of Myosin molecule
- Myofibrils shorten since Actin molecules have been pulled together
- Presynaptic
- Sensory Output (Kinesthesis)
- Muscle Spindles - muscle length detector
- MS1 - Slow Movement detection
- MS2 - Fast Movement detection
- Golgi Tendon Organ - tendon force detector
- Muscle Spindles - muscle length detector
- Structure
