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S&F- Chapter 7- Musc
les- Terms
Term | Definition |
---|---|
abduction | moving away from the midline of the body, opposite motion of adduction |
actin | contractile protein found in the thin myofilaments of skeletal muscle |
adduction | moving toward the midline of the body, opposite motion of abduction |
all or none | when stimulated, a muscle fiber will contract fully or not at all; whether a contraction occurs depends on whether the stimulus reaches the required threshold |
antagonist (muscle) | those having opposing actions; for example, muscles that flex the upper arm are antagonists to muscles that extend it |
atrophy | wasting away of tissue; decrease in size of a part; sometimes referred to as disuse atrophy |
bursa | small, cusionlike sac found between moving body parts, making movement easier |
dorsiflexion | when the top of the foot is elevated (brought towardthe front of the lower leg) with the toes pointing upward |
extension | increasing the angle between two bones at a joint |
fatigue | loss of muscle power; weakness |
flexion | act of bending; decreasing the angle between two bones at the joint |
hypertrophy | increased size of a part casuse dby and increase in the size of its cells |
hypothermia | subnormal core body temperature below 37 degrees C |
insertion | attachment of a muscle to the bone that it moves when contraction occurs (as distinguished from its origin) |
isometric | type of muscle contraction in which muscle does not shorten |
isotonic | of the same tension or pressure |
motor neuron | transmits nerve impulses from the brain and spinal cord to muscles and glandular epithelial tissues |
motor unit | a single motor neuron with the muscle cells it innervates |
myofilaments | ultramicroscopic, threadlike structures found in myofibrils |
myosin | contractile protein found in the thick filaments of skeletal muscle |
neuromuscular junction | the point of contact between the nerve endings and muscle fibers |
origin | the attachment of a muscle to the bone tat does not move when contraction occurs, as distiguished from insertion |
oxygen debt | continued increased metabolism that occurs in a cell to remove excess lactic acid that resulted from exercise |
paralysis | loss of the power of motion, especially voluntary motion |
plantar flexion | the bottom of the foot is directed downward; this motion allows a person to stand on his or her tiptoes |
posture | position of the body |
prime mover | the muscle responsible for producing a particular movement |
pronation (pronate) | to turn the palm downward |
rotation | movement around a longitudinal axia; for example, shaking your head "no" |
sarcomere | contractile unit of muscle; length of a myofibril between two Z bands |
sliding filament theory | explanation of how a skeletal muscle contracts |
stimulus | agent that causes a change in the activity of a structure |
supination (supinate) | to turn the palm of the hand upward; opposite of pronate |
synergist | muscle that assists a prime mover |
tendon(s) | bands or cords of fibrous connective tissue that attach a muscle to a bone or other structure |
tenosynovitis | inflammation of a tendon sheath |
tetanic contraction | sustained contraction |
tonic contraction | special type of skeletal muscle contraction used to maintain posture |