Chapter 1: Structure and Function of the Muscular, Nervous, and Skeletal Systems Flashcards
Epimysium
The connective tissue encasing the entire muscle body. (NSCA CPT, pg. 21)
Perimysium
The connective tissue encasing groups of muscle fibers (fascicles). (NSCA CPT, pg. 22)
Endomysium
The connective tissue encasing individual muscle fibers. (NSCA CPT, pg. 22)
Muscle Fiber
The structural unit of muscle. Also referred to as a muscle cell. (NSCA CPT, pg. 22)
Fascicle
Bundle of muscle fibers; plural of fasciculus is fasciculi. (NSCA CPT, pg. 22)
Action Potential
A temporary change (reversal) in the electrical charge of a muscle or nerve cell when it is stimulated. (NSCA CPT, pg. 22)
Mitochondria
Specialized cellular organelles where the reactions of aerobic metabolism occur. (NSCA CPT, pg. 23)
Sarcoplasmic Reticulum
Highly specialized net- work system in a muscle fiber that stores calcium ions. (NSCA CPT, pg. 23)
Myofibril
The elements of a muscle fiber that primarily consist of actin and myosin. (NSCA CPT, pg. 23)
Myofilaments
The two primary proteins in a myofibril (i.e., actin and myosin). (NSCA CPT, pg. 24)
Myosin
One of the two primary myofilaments; binds with actin to cause a muscle action. (NSCA CPT, pg. 24)
Actin
One of the two primary myofilaments; binds with myosin to cause a muscle action. (NSCA CPT, pg. 24)
Tropomyosin
A protein, attached to actin, that prevents actin from binding to the myosin cross- bridges. (NSCA CPT, pg. 25)
Troponin
A protein, attached to tropomyosin, that when activated shifts the tropomyosin to allow the actin to bind to the myosin cross-bridges. (NSCA CPT, pg. 25)
Sarcomere
The segment of a myofibril between two adjacent Z-lines (bands), representing the functional unit of skeletal muscle. (NSCA CPT, pg. 25)
Adenosine Triphosphate
The universal energy-carrying molecule manufactured in all living cells as a means of capturing and storing energy. (NSCA CPT, pg. 27)
Concentric Muscle Action
A muscle action in which the muscle is able to overcome the resistance, leading to muscle shortening. (NSCA CPT, pg. 27)
Eccentric Muscle Action
Action that occurs when a muscle cannot develop sufficient tension and is overcome by an external load, and thus progressively lengthens. (NSCA CPT, pg. 27)
Isometric (static) Muscle Action
Action that occurs when a muscle generates a force against a resistance but does not overcome it, so that no movement takes place. (NSCA CPT, pg. 27)
Myoglobin
Iron-containing protein in muscle cells that stores oxygen for use in cell respiration. (NSCA CPT, pg. 28)
Type I Muscle Fibers
A type of muscle fiber char- acterized by a slow rate of action and relaxation, high aerobic metabolic activity, and high fatigue resistance. Also known as a slow oxidative or slow-twitch fiber. (NSCA CPT, pg. 28)
Type IIa Muscle Fibers
A type of muscle fiber char- acterized by a fast rate of action and relaxation, moderate aerobic and high glycolytic metabolic activity, and moderate fatigue resistance. Also known as a fast oxidative glycolytic fiber. (NSCA CPT, pg. 28)
Type IIx Muscle fibers
A type of muscle fiber char- acterized by a fast rate of action and relaxation, high glycolytic metabolic activity, and low fatigue resistance. Also known as a fast glycolytic fiber. (NSCA CPT, pg. 28)
Muscle Spindle
Sensory organ within muscle fibers that relays sensory information about length and speed of stretch to the central nervous system. (NSCA CPT, pg. 30)