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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 - PowerPoint PPT Presentation
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Muscular System
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-none response, 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 pulledATP 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 bendExtensors- 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