Locomotion and Movement

∙ Every living organism, whether it is unicellular or multicellular, need support to keep its shape & to move. 

∙ Movement is one of the significant features of living beings. Animals and plants exhibit a wide range of movements. 

∙ Streaming of protoplasm in the unicellular organisms like Amoeba is a simple form of movement. Cytoplasmic streaming assists in the delivery of nutrients, metabolites and other materials to all parts of the cell. 

∙ Movement of cilia, flagella and tentacles are shown by many organisms. Human beings can move limbs, jaws, eyelids, tongue, etc. 

∙ Some of the movements result in a change of place or location. Such voluntary movements are called locomotion. Walking, running, climbing, flying, swimming are all some forms of locomotory movements. 

∙ Movement is the temporary or permanent displacement of a body or its parts from its original position. Locomotion, on the other hand is the displacement of the entire body from one place to another.  

∙ Locomotory structures need not be different from those affecting other types of movements. For example, in Paramecium, cilia helps in the movement of food through cytopharynx and in locomotion as well. Hydra can use its tentacles for capturing its prey and also use them for locomotion. 

Paramecium

∙ Flagellar movement helps in the swimming of sperm, maintenance of water current in the canal system of sponges and in locomotion of Protozoans like Euglena. We use limbs for changes in body postures and locomotion as well. Movements and locomotion cannot be studied separately, the two may be linked by stating that all locomotion are movements but all movements are not locomotion. 

∙ Methods of locomotion performed by animals vary with their habitats and the demand of the situation. However, locomotion is generally for search of food, shelter, mate, suitable breeding grounds, favourable climatic conditions or to escape from enemies/predators.

1.0Types of Movement 

Cells of the human body exhibit three main types of movements, namely, amoeboid, ciliary and muscular. 

Amoeboid Movement

Movement in the fashion of an amoeba i.e. by pseudopodia. Some specialised cells in our body like macrophages and leucocytes in blood exhibit amoeboid movement. It is effected by pseudopodia formed by the streaming of protoplasm (as in Amoeba). Cytoskeletal elements like microfilaments are also involved in amoeboid movement.

Pseudopodia formation Ciliary movement

A specialized arrangement of microtubule is responsible for the beating of cilia, microtubule containing extensions that projects from some cells. Ciliary movement occurs in organs which are lined by ciliated epithelium. The coordinated movements of cilia in the trachea help us in removing dust particles and some of the foreign substances inhaled along with the atmospheric air. Passage of ova through the female reproductive tract is also facilitated by the ciliary movement. 

Ciliated epithelium in respiratory tract

Muscular Movement

Movement of our limbs, jaws, tongue, etc, require muscular movement. Nearly all movement in the human body is the result of muscle contraction. The contractile property of muscles are effectively used for locomotion and other movements by human beings and majority of multicellular organisms. Locomotion requires a perfect coordinated activity of muscular, skeletal and neural systems. 

Muscular system

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