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The Muscular System Chapter 7. “I have husbandry”. What do we call the study of muscles?. The Muscular System. > 600 muscles > half of body weight Determines form Maintains posture Produces body heat Forms internal organs. Tendon : Attaches muscle to bone.
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The Muscular SystemChapter 7 “I have husbandry”
The Muscular System • > 600 muscles • > half of body weight • Determines form • Maintains posture • Produces body heat • Forms internal organs
Attaching to a muscle…Origin: The less movable of the two points of attachment to a bone. Attaches to the fixed part of the skeleton.
Insertion: The point of attachment by a muscle to a moveable bone. Moves when a muscle is contracted.
Motor nerve: Causes a muscle to move by stimulating a group of muscle fibers
Speed of muscle movement varies with muscle & size of structure to be moved…
Muscles are classified based on function, shape, and structure…
Skeletal muscle: • “Voluntary” because is controlled at will • “Striated” because of striped microscopic appearance • Fibers become shorter and thicker when muscle contracts
Smooth Muscle: • Also called visceral, nonstriated or involuntary muscle • Many internal organs are made of smooth muscle…
Cardiac muscle is involuntary but does show very fine striations
cardiac striated smooth
Muscle Attachments: • Attachment to tendons (phalanges) results in movement and reduces bulk • Voluntary muscles usually attach to bone. • Attach to cartilage in larynx & thorax
Muscles may also be attached to skin, mucous membranes or the fascia of other muscles.