The Muscular System...The Muscular System Muscles are responsible for all types of body movement All...
Transcript of The Muscular System...The Muscular System Muscles are responsible for all types of body movement All...
The Muscular System
Muscles are responsible for all types of body movement
All muscles share some terminologyPrefixes myo and mys refer to “muscle”Prefix sarco refers to “flesh”
What are the 3 types of muscle tissue?
Connective Tissue Wrappings of Skeletal Muscle
– Endomysium—encloses a single muscle fiber
–Perimysium—wraps around a fascicle (bundle) of muscle fibers
– Epimysium—covers the entire skeletal muscle
– Fascia—on the outside of the epimysium
(This is the tough layer you will need to break through to separate one muscle from another during the chicken
leg dissection)
–Muscle fiber = Muscle cell
Connective Tissue Wrappings of Skeletal Muscle
Microscopic Anatomy of Skeletal Muscle
Sarcolemma—specialized plasma membraneMyofibrils—long organelles inside muscle cellI band – light bandA band- dark band
Sarcomere—contractile unit of a muscle fiberOrganization of the sarcomere
MyofilamentsThick filaments = myosin filamentsThin filaments = actin filaments
The Sliding Filament Theory of Muscle Contraction
The Sliding Filament Theory of Muscle Contraction
• Activation by nerve causes myosin heads (cross bridges) to attach to binding sites on the actin (thin) filament
• Myosin heads pull the actin toward the center of the sarcomere
Actin
Myosin
Head
• This continued action causes a sliding of the myosin along the actin
• The result is that the muscle is shortened (contracted)