Chapter 5 - Muscular System Flashcards
Musculotendinous
point where muscle meets tendon
Tenoperiosteal junction
point where tendon meets bone
Insertion
more moveable bone and moves toward origin
Origin
more stable bone, fixed
Reverse muscle action
instead of the insertion moving toward the origin, the origin is now moving toward the insertion
Parallel muscle
fibers tend to be longer and thus have a greater potential for shortening and producing more ROM
Oblique muscles
fibers tend to be shorter but are more numerous per given area than parallel fibers and tend to have a greater strength potential but smaller ROM potential
Strap muscles
long and thin fibers running the entire length of the muscle
Fusiform muscle
similar shape of a spindle
Rhomboidal muscle
four sided, usually flat with broad attachment at each end
Triangular muscles
flat and fan-shaped with fibers radiating from a narrow attachment at one end of a broad attachment at the other
Unipennate muscles
look like one side of a feather
Bipennate muscle
look like a feather
Multipennate muscle
have many tendons with oblique fibers in between
Normal resting length
length of a muscles when it is not shorted or lengthened, no forces or stresses placed upon it
Irritability
ability to respond to a stimulus
Contractility
muscle’s ability to contract and generate force when it recieves adequate stimulation
Extensibility
muscles ability to stretch or lengthen when a force is applied
Elasticity
muscles ability to recoil or return to normal resting length when the stretching or shortening forces is removed
Fascicles
bundles of muscles
Myofibrils
each individual muscle fiber is composed of a smaller bundle
Sarcomeres
myofibrils partitioned longitudinally into functional divisions, capable of shortening when stimulated
Z-lines
seperated sarcomeres from each other
Sliding filament theory
interaction between the actin and myosin, explaining how force is produced during a muscle contraction and how the sarcomere is shortened
Muscles tension
force built up within a muscle
Tone
slight tension that is present in a muscle at all times, even when the muscles is resting
Excursion
distance from a maximum lengthening to maximum shortening
Optimal length
when a muscle has a slight stretch but is not overstretched
Active insufficiency
point at which a muscle cannot shorten any farther
Passive insufficiency
when a multijoint muscle cannot be lengthened any farther without damage to its fibers
Adaptive lengthening
strengthening of overstretched muscles
Adaptive shortening
resting muscle length and amount of extensibility decrease
Tenodesis
when the wrist is extended the fingers and thumb flex into the palm and then when the wrist is flexed the fingers and thumb open
Isometric contraction
when a muscle contracts, producing force without changing length of a muscle
Concentric contraction
when there is joint movement, the muscles shorten, and the muscle attachments move toward each other
Eccentric contraction
when there is joint motino but the muscle appears to lengthen; muscle attachments separate
Gravity eliminated position
position used if a muscle is too weak to move against gravity to exercise
Isokinetic contraction
less common type of muscle contraction - speed of motion stays the same for the duration of the contraction
Agonist
muscle or muscle group that causes the motion
Prime mover
muscle that provides the primary force driving the action
Assisting mover
muscle that is not as effective but does assist in providing motion
Antagonist
muscle that performs the opposite motion of the agonist
Cocontraction
when the antagonist contracts at the same time as the agonist
Stabilizer
muscle or muscle group that supports, or makes firm, a part allowing the agonist to work more efficiently
Neutralizer
contraction to prevent the unwatned motion if a muscle can do two or more actions but only one is wanted
Synergist
nonspecific term descibing a muscle that work with one or more other muscles to enhance a particular motion
Closed kinetic chain
distal segment is fixed (closed) and the proximal segment(s) move
Open kinetic chain
distal segment is free
Trigger points
hyperirritable points within a tight band of muscle that refer pain to other areas of the body when they are active or palpated
