Tuesday, July 11, 2017

LOCOMOTION AND MOVEMENT

Types of Movements
On the basis of structure, three basic types of movements occur in the cells of human body namely
amoeboid, ciliary and muscular.
(i) Amoeboid or Pseudopodial Movements :
Due to the streaming of protoplasm or cytoplasm, the
surface of the cell forms false feet or pseudopodia. The old pseudopodia are replaced by the new
pseudopodia and therefore the formation and withdrawl of it allows the cell to change its shape regularly.
As Amoeba, WBC, and macrophages show pseudopodial movements they do not have a fixed shape.
The leucocytes and macrophages reach each and every part of the body and engulf the antigens or
pathogens through these pseudopodia.
(ii) Ciliary Movements :
The free surface of the cells have short fine hair-like projections called cilia. The
movement of these projections (cilia) is called ciliary movement. The oar-like activity of the cilia creates
a water current which helps in movement of various structures. The tubular structures of human body
such as respiratory tract, reproductive tract are lined by ciliated epithelium and help in the movement
of various substances. In oviduct, cilia provide the motive force for the passage of ova. Coordinated
movement of cilia in trachea helps in the removal of dust particles inhaled along with atmospheric air.
Spermatozoa and protozoa have flagella for locomotion and movement,

(iii) Muscular Movement :
In humans, movement of limbs, jaw, tongue and other body parts occur due to
contraction of muscles. The muscles contract and relax rhythmically to produce movement and are used
effectively for locomotion.