PHYSIOLOGY OF NERVE AND MUSCLE CELLS lecture 13

O B J E C T I V E S :
AT THE END OF THE LECTURE YOU SHOULD BE ABLE TO
•Illustrate the Treppe phenomenon.
•Understand the Energy Sources & Metabolism of the skeletal muscle.
•Define O2 dept mechanisms.
•Describe various types of heat production in skeletal muscles.
•Explain short notes about Electromyography.
•Definition: An increase in the strength of twitches in response to repeated stimuli of the same strength.
• i.e., If twitch duration = 30 msec
• Applying stimulation every 50 msec ? the muscle has the time to recover between the stimuli and the recorded twitches are identical.
• Stimulating the muscle more frequently (every 35 msec), the muscle still fully relaxes between the stimuli but the successive twitches develop more tension.
Treppe or Stair PhenomenonMuscle contraction requires energy,
•Muscle has been called “a machine for converting chemical energy into mechanical work”
Energy Sources & Metabolism
Energy Sources & Metabolism
•The immediate source of energy is ATP, formed by the metabolism of carbohydrates and lipids.
•ATP is resynthesized from ADP by the addition of a phosphate group.
•Some of the energy for this endothermic reaction is supplied by the breakdown of glucose to CO2 and H2O, but
•there also exists in muscle another energy-rich phosphate compound that can supply this energy for short periods.