Ch 44 Muscles Flashcards
Axial skeleton
the bones of the body axis, including the skull, vertebral column, ribs, and sternum.
Appendicular skeleton
the bones of the limbs and supporting thoracic (pectoral) and pelvic girdles.
Bone
A relatively hard component of the vertebrate skeleton, a living, dynamic tissue composed of organic molecules and minerals.
Fascicle
a small bundle or cluster, especially of nerve, tendon, or muscle fibers.
Sarcomere
One complete unit of the repeating pattern of thick and thin filaments within a myofibril.
Myofibril
rodlike collection of myofilaments within a muscle fiber (cell); contains thick and thin filaments. OR Each skeletal muscle fiber is a single cell with multiple nuclei, containing numerous cylindrical bundles.
Striated muscle
Skeletal and cardiac with a series of light and dark bands perpendicular to the muscle’s long axis.
Tropomyosin
A rod-shaped protein that plays an important role in regulating muscle contraction.
Troponin
A small globular-shaped protein that plays an important role in regulating muscle contraction through its ability to bind Ca2+.
Excitation–contraction coupling
The sequence of events by which an action potential in the plasma membrane of a muscle fiber leads to cross-bridge activity.
Sarcoplasmic reticulum
A cellular organelle that provides a muscle fiber’s source of the calcium involved in muscle contraction: A specialized form of the endoplasmic reticulum.
T-tubules
Invaginations of the plasma membrane that open to the extracellular fluid.
Flexor
A muscle that bends a limb at a joint.
Extensor
A muscle that straightens a limb at a joint.
Antagonists
A muscle or group of muscles that produces oppositely directed movements at a joint.
