how movement is brought about in a limb
Post on 18-Nov-2014
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How movement is brought about in a
limb
Azneezal Ar-RashidSmk Sri Aman
95007 Sri Aman, Sarawak
February 2010
• A muscle is attached to at least two bones across joints through tendons
• Tendons :– Strong– Tough– Inelastic
• Antagonistic pairs– One muscle contracts– One muscle relaxes
• Example :– Bending & straightening
the arm
• Arm– Front : biceps
• When biceps contracts, triceps relaxes
– Forearm moves upwards
– Back : triceps
The structure of muscle
• Muscle– Consists of :
• Muscle fibres• Blood vessels• Nerves
• Muscle fibres– Single & long
cylindrical cell– Many nuclei– Made up of myofibrils
• Two types of protein filaments :
– Actin– Myosin
– Note : interaction between actin & myosin causes muscle contraction
• Has nerve ending– Voluntary actions
• Signal from the brain
• Has mitochondria– Energy : ATP for muscle
contractions
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