Describe what happens physiologically when a muscle contracts and relaxes


Each skeletal muscle is composed of many muscle fibers (cells), each of which has the ability to contract or relax. A muscle fiber contracts when it receives a nerve impulse from the central nervous system (brain and spinal cord). After contracting, a muscle fiber relaxes until it receives another nerve impulse.

Health & Biomechanics

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The top three causes of death among Americans age 15 to 24 are

A. accidents, homicide, and suicide. B. accidents, smoking, and cancer. C. homicide, cancer, and accidents. D. smoking, high blood pressure, and suicide.

Health & Biomechanics

April, a 19-year-old female who weighs 160 pounds and has 30 percent body fat, would like to know her recommended body weight at 22 percent body fat. Fat weight (lb) = Body weight (lb) × Percent body fat Lean body mass (lb) = Body weight (lb) ? Fat weight (lb) Recommended body weight (lb) = Lean body weight (lb) ÷ (1.0 ? Desired body fat percentage)   What is April's lean body weight?

A. 35.2 lb B. 48 lb C. 112 lb D. 144 lb E. 83.2 lb

Health & Biomechanics

Which of the following statements about sleep is correct?

A) Sleep is a state of "global shutdown." B) Sleep is prompted by darkness. C) Sleep is physiologically prompted. D) Sleep is prompted by silence and other reductions in stimulation from the environment.

Health & Biomechanics

Bronchodilator: __________

Fill in the blank(s) with correct word

Health & Biomechanics