skeletal and muscular systems. skeletal system the framework for your body 206 bones “os-” bone;...
Post on 18-Dec-2015
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Bone contains:
• Minerals – especially calcium which provides for the hardness of bone
• Collagen fibers which provides strength of bone
Joint
• “art-” and “arthr-” mean joint
• Ligaments stabilize joints
• Cartilage caps the bones at the joint for a smooth surface
Skeleton Function
• Framework
• Support
• Movement
• Protection
• Blood cell production from bone marrow
• Storage of minerals & fat
Cause
• Inadequate calcium
• Females, older more commonly
• Sedentary lifestyle
• Poor diet
• Pregnancy giving calcium to fetus
• Menopause lead to calcium withdrawal from bone
Prevention/Treatment
• Weight-bearing exercise
• Calcium in diet
• Estrogen replacement therapy after menopause
• Drugs, such as Fosamax
Arthritis
• Rheumatoid arthritis is an autoimmune disease in which the immune system attacks the joints in the body leading to their gradual destruction
Sprain
• Joint injury that stretches or tears supportive ligaments
• A severe sprain can result in a dislocation
Smooth muscle
• Found in the wall of tubular structures such as intestine
• Involuntary
• Smooth appearance microscopically
• Peristalsis is a wave like contraction of smooth muscle
Microscopic Muscle
• Myofiber = muscle cell
• Myofibril = the striated parts of the muscle cell
• Myofilaments = the proteins that make up the myofibrils
Myofilaments
• The two main proteins that comprise the myofilaments are:– Myosin – very thick protein– Actin – very thin protein
Sarcomere
• The actin and myosin in the muscle cells are arranged in small groups called SARCOMERES
• Since contraction occurs at the microscopic level of the sarcomere, the sarcomere is the functional unit of contraction
Sliding Filament Theory
• This describes the mechanics of muscle contraction
• The myosin “heads” grab on to the actin protein and pull the actin towards the center of the sarcomere, making the sarcomere shorter.
Motor Neuron
• Skeletal muscle will not contract unless a motor neuron (movement nerve cell) stimulates it to contract
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