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Muscular System. Muscular System. Series of tissues throughout the body that act to move bones or organs Divided into: Skeletal Smooth Cardiac . Divisions of the System. Skeletal- “striated”- found pulling skeleton, arranged in stripes
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Muscular System • Series of tissues throughout thebody that act to move bones or organs • Divided into: • Skeletal • Smooth • Cardiac
Divisions of the System Skeletal- “striated”- found pullingskeleton, arranged in stripes Smooth- found lining digestive andparts of circulatory system Cardiac- in heart only, constantlycontracting
Muscle Contraction Nerve impulse travels to nerve tellingit to contract Must receive enough signal that itreaches its threshold, which tells themuscle to contract - threshold is point at which muscle will contract
Muscle Contraction • Muscle contraction is all-or-noneresponse, much like nerve • If muscle gets enough signal,it will contract. If not, it willnot react at all.
Chemical Energy When it is time for your cells tocontract, they must use chemicalenergy in the form of ATP Adenosine TRIphosphate- one P isremoved making ADP (adenosineDiphosphate). The energy from theP bond results in energy for movement
Process of Contraction Actin and myosin are proteins withina muscle Actin attaches to the myosin’s “head”,and gets pulled ATP is used, causing myosin to rebindfurther down the actin and pull again
Sliding Fillament Model The myosin contraction causes theactin to “slide” along the myosin strands, pulling the muscle This is a muscle contraction
Muscle Contraction As myosin pulls, the muscle becomesshorter, or contracts There are two types of muscle- Flexors- shorten causing a twobones to bend Extensors- shorten pulling the bones straight
Muscle Structure Origin- The non-moveable point towhich the muscle is attached Insertion- the attachment to the bonethat is moved by the muscle
Muscle Issues • Sprain vs. Strain • Muscular Dystrophy
Sprain vs. Strain • Sprain- stretch/tear of ligament • Strain- stretch/tear of tendon • Graded I-III • I- ice • II- immobilize, limit movement • III- immobilize, may need surgery
Muscular Dystrophy Sex-linked inherited degenerativedisease Results in loss of muscle tissue, oftenresults in death at a young age *commomly- Recessive, inherited on X chromosome, so only affects males