Muscle Bundle = group of muscle fibers (muscle cells) that function together and are bound together by fascia (connective tissue). Examples: biceps brachii, trapezius, pectoralis major. Origin Insertion Belly Prime mover = muscle that provides the primary movement at a joint. In this Example: Biceps brachii Synergist = muscle that Assists the prime mover. In this case the brachialis Antagonist = muscle that opposes The prime mover. In this example: Triceps brachii.

Bone Tendon Fascia Fascicle Muscle Fiber Sarcolemma Sarcoplasmic Reticulum Transverse Tubule Sarcomere Z-line

Sliding Filament Hypothesis Z-lineActinMyosin Z-line Myosin Heads Fully Stretched Partially Contracted Fully Contracted Sarcomere Shortening

Myosin Head in the relaxed conformation Tropomyosin covering Binding sites ATP Ca

Motor neuron Axon Neuromuscular junction Vesicle containing Neurotransmitter (acetylcholine) Transverse tubule Ca 2+ active Transport pump Ca 2+

Motor Unit = motor neuron and the muscle Cells that it stimulates Motor neuron Branches to Stimulate 4 cells Different neuron branches to stimulate 8 different cells

Neuromuscular Junction Motor neuron axon Neuromuscular Junction Vesicles containing Neurotransmitter (acetylcholine) Sarcolemma (muscle cell membrane)

Neuromuscular Junction