Figure 3 illustrates an example of a Class III lever. In this type of lever, the moving force is between the fulcrum and the load. A real life example of this sort of lever is carrying a loaded shovel. An example in the human body is drinking from a mug as you bring it from the table to your mouth. Irritability is the ability of the tissue to receive and respond to stimuli.
Contractility is the ability to shorten and thicken after sufficient stimulus.
Extensibility means that it can be stretched. Obvious motions include walking, running, locomotion. This relies on the integrated functioning of bones, joints and muscles attached to bones. Less noticeable motions include your heart beating, your stomach wiggling, peristalsis, your gall bladder contracting and the contraction of your urinary bladder. Contractions of the muscles hold the body in stationary positions, e.g., sitting, standing, to maintain your posture.