Muscular System (Part-III)

Introduction: In human well developed limb system exists for the locomotion. Together muscle-skeletal-nerve system coordination results the locomotion. Here we discuss the different types of muscle contraction and their mode of action.

Types of muscle contraction in human:
Three types of muscles present in human which we discussed in previous lecture. Skeletal muscles are mainly involving in the locomotion by contraction. Contraction of the skeletal muscle underlie in two different class. They are Twits contraction and tetranic contraction. Voluntary muscles contractions are differentiated as concentric, eccentric, isometric and isotonic contraction. Cardiac muscle contraction can be include in tetranic contraction but molecular level difference can be seen (Figure 17.1).

Twitch contraction: It is a very short timed muscle contraction. In response to stimuli, muscle contract and relax but before reaching the peak muscle start to relax.

Tetranic contraction: In comparison to twitch contraction, tetranic contraction is a longer contraction. In response to stimuli, muscles contract, stabilize and then relax in a sequence manner. Duration of the stable condition vary depend on the strength of the stimuli.

Concentric contraction: In order to overcome the resistance with generated energy, muscle contracts and shortens. This contraction can be seen in bicep contraction, angle change in joints.

Eccentric contraction: Due to the lack of energy generation to overcome the external response, muscle contract and lengthen.The response is slightly delayed one when compare to the concentric contraction.

Isometric contraction: No variation can find in muscle length in response to the external force. So there is no movement.

Isotonic contraction: The excessive force on the muscle initially contracts and later increases the muscle length. The muscle length increase in response to the external force.