EX1 LAB PHYSIO

• Phases of a simple muscle contraction:

  • Latent period (0.01 second):
  • Begins from the application of the stimulus to the beginning of the response
  • Represents the time necessary for physico-chemical changes for cellular response
  • Represents the time required for the physiological disturbance resulting from stimulation to travel to the whole organ
  • Period of contraction (0.05 seconds):
  • Corresponds to the upstroke of the writing lever
  • Signifies that the muscles have performed work
  • Period of relaxation (0.06 second):
• • Muscle returns to its original resting state
  • Time for resynthesis of products utilized by the muscle during activity so it can respond to succeeding stimuli
• Different types of muscles with respect to duration of contraction:

  • Skeletal muscle:
  • Fastest contraction with the shortest duration among the three types
  • Smooth muscle:
  • Longest duration of contraction, ten times as long as skeletal muscle
  • Cardiac muscle:
  • Intermediate between skeletal and smooth muscles