Smooth Muscle Stiffness Variation Due to External Oscillation

The static and dynamic stiffnesses of contracted trachea smooth muscles are determined before, during and after length oscillations in isometric contraction. An appropriate Neural Network model is developed to normalize the data. The results indicate that the dynamic stiffness has the tendency of decreasing as the frequency and/or amplitude of external excitation increases. However, the static stiffness decreases with an increase in the frequency and amplitude of excitation until it reaches a critical value of frequency where no variation in stiffness is observed. It is postulated that the tissue elasticity and inertia are the main contributors to the dynamic stiffness while the myosin-actin cross bridge cycling is the main contributor to the static stiffness.