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3 Cards in this Set
- Front
- Back
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List, locate, and discuss the structure and function of the three major types of muscle tissue |
1.Skeletal S: 40-50% body weight, crossfire stripes or striations, contractions can be voluntarily controlled F: every movement made is is produced by contractions 2. Cardiac S: composes bulk of heart, cardiac muscle cells bench frequently, characterized by unique dark bands called intercalated disks, interconnected nature of cardiac muscle cells allows heart to contract efficiently as a unit F: help cells pump blood through the heart 3. Smooth S:lacks cross stripes, or striations, found in walls of hollow visceral structures such as digestive tract, blood vessels, and ureters, movement caused by contractions are involuntary F:help pump liquids through our other hollow organs FUNCTION:specialize in contratin or shortening |
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How is a muscle stimulated and compare the major types of skeletal muscle contractions |
Muscle stimulation: will contract only if an applied stimulus reaches a certain minimal level of intensity- called threshold stimulus. once stimulated by a threshold stimulus, a muscle finer will contract completely, a response called all or none. diff muscle fibres in a muscle are controlled by a differ motor units having different threshold stimulus levels: individual muscle fibres respond in an all or none, muscles as a whole does not. diff motor units responding to a diff threshold stimuli permit a muscle as a whole to execute contradictions of graded force Twitch and tetanic contractions: twitch (quick, jerky responses to a stimulus), tetanic (sustained and steady, caused by a series of stimuli bombarding a muscle in a rapid succession Isotonic contractions: contraction of a muscle that produces movement at a joint, muscle changes length, causing the insertion en of the muscle to move relative to the point of origin, concentric contractions shortened muscles, eccentric contractions allow muscles to increase in length. Isometric contractions: do not produce movement, the muscle as a whole does not shorten, tension increases |
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most common types of movement produced by skeletal muscles |
Flexion: decreases the angle b/w 2 bones at their joint: bending Extension: increases the angle b/w 2 bones at their joint: straightening Abduction:movement of a part away from the midline of the body Adduction: movement of a part toward the midline of the body Rotation and circumduction:around a longitudinal axis Supination and pronation:hand positions by rotation of the forearm, supination (palm face anterior) pronation (palm face posterior) Dorsiflexion and plantar flexion: foot movements, dorsiflexion (elevation of the top of foot), plantar (the bottom of the foot is directed downward) Inversion and eversion: foot movements, inversion ( rotates ankle toward median), eversion (rotates ankle away from median) |
