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Anatomy: Muscles
Term | Definition |
---|---|
contractility | the ability of skeletal muscle to shorten with force |
excitability | the capacity of skeletal muscle to respond to a stimulus |
extensibility | the ability to be stretched |
elasticity | ability to recoil to their original resting length after they have been stretched |
each skeletal muscle is surrounded by a connective tissue sheath called the _____? | epimysium |
another connective tissue located outside the epimysium. it surrounds and separates muscles? | fascia |
a muscle is composed of numerous visible bundles called muscle fasciculi, which is surrounded by loose connective tissue called _____? | perimysium |
the fasciculi are composed of single muscle cells called _____? | fibers |
Each muscle fiber is a single cylindrical cell containing _____ _______? | several nuclei |
each fiber is surrounded by a connective tissue sheath called the _____? | endomysium |
the cytoplasm of each fiber is filled with _____? | myofibrils |
myofibrils | threadlike structure that extends from one end of the fiber to the other |
myofibrils consist of 2 major kinds of protein fibers ? | actin myofilaments and myosin myofilaments |
actin myofilaments | thin myofilaments. They resemble 2 minute strands of pearls twisted together. |
myosin myofilaments | thick myofilaments. They resemble bundles of minute golf clubs. |
actin and myosin filaments form highly ordered units called ______? | sarcomeres |
sarcomere | the basic structural and functional unity of the muscle |
_____? are joined end to end to form the myofibril | sarcomeres |
each sarcomere extends from one z line to another z line . each z line is an attachment site for _____? | actin |
the arrangement of actin and myosin give a ____ appearance? | banded |
on each side of the z line is a light area called an I band, it consists of _____? | actin |
the _ _____ extends the length of of the myosin? | A band |
the A band is the _______ central region in each sarcomere? | darker |
in the center of each sarcomere is another light area called the _ ____, which consists of only myosin? | H zone |
the myosin myofilaments are anchored in the center of the sarcomere at a dark staining band called the _ ____? | M line |