How does the nervous tissue cause action
How the nervous system collects information from all parts of the body, processes this information, makes a suitable decision, and then conveys it to muscles for appropriate action. In other words, we can say that it is the muscular tissue which performs the ultimate job, the movements and many more. Now the question comes in our mind is how the animal muscles move.
Movements of our body parts are caused by the contraction of muscles. Muscles are composed of many elongated cells called muscle fibres, which are able to contract and relax.
Muscles are generally of three types - skeletal (voluntary), smooth (involuntary) and cardiac. The skeleton muscles are innervated by the voluntary nervous and are concerned with movement (locomotion). The smooth muscles, which are present in the blood vessels, digestive tract, and other internal organs are innervated by the autonomic nerves. Whereas the cardiac muscles, which found only in the heart, contract spontaneously and are also innervated by the autonomic nerves.
The skeleton muscles perform work by contracting and never by relaxing. Thus, muscle cell move by changing their shape. You may ask how the muscle cells change their shape. Muscle cells have a special proteins (actin and myosin) that change both their shape and arrangement in the cells in response to nervous electrical impulses, and eventually cause contraction of the muscle cell.