Human Body Systems

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Human Body Systems

• Lesson 20 Terms and Definitions

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• Q What is force and what does it have to do with
  muscle strength?

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3 types of Muscles
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Involuntary Muscles

• Cardiac and Smooth muscles are both involuntary
  muscles.
• Involuntary Muscles operate automatically.
• Heart beats automatically
• Food is digested automatically

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Cardiac Muscles

• Cardiac Muscle (heart muscle) pumps blood through
  the circulatory system.
• Involuntary, very strong
• Striated

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Smooth Muscles

• Smooth Muscle lines the digestive tract, and
  blood vessels creating wave like motions.
• Involuntary

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Voluntary Muscles

• Skeletal muscles
• Within someones conscious control.
• Only involuntary action is through a reflex.

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Skeletal Muscles

• Skeletal Muscles work together with bones to
  cause the movement of the body.
• Voluntary, VERY strong
• Striated
• 620 skeletal muscles

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Skeletal muscles

• Energy in muscle fibers comes from mitochondria.
• The more mitochondria the more energy (as long
  as there is enough O2)

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Muscle Contractions

• Contraction STARTS by a nerve impulse from the
  central nervous system.
• Receives an electrical signal from nerve and is
  preparing to contract.
• Actual Contraction (2/3s its size).
• Relaxation when muscle returns to its original
  length.

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Videos

• Discovery Education
• The Human Body Pushing the Limits
• Segments
• Muscles Superhuman Strength (6min)
• Muscle Memory Learning While you sleep (4 min)
• Other movie in the Chapter 20 folder

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Size vs Strength Lab

• Force the push or pull of an object
• newton (N) unit of measurement of force
• (Number of kilograms) x 9.8 newtons