MOVEMENT AND ITS TYPES:
· Movement is one of the significant features of all living organisms; we move our body parts for doing many kinds of work like tongue for talking, jaws and teeth while eating.
· The movement of our eyelids is an involuntary function. So, we can say that every second some or other part of our body exhibits some or other kind of movement.
· The act of changing place or position by the entire body or by one or more of its parts is called movement.
· Movement is one of the characteristic features of living organisms.
· Study of movement is called kinesiology.
· In animals, movement is of two types: muscular and non- muscular.
· Muscular movements are further divided into two types: locomotion and movement of body parts.
· Locomotion is the movement of an animal as a whole from one place to another place.
Types of Movement:
Ø Movement involves four basic mechanisms. They are:
1. Amoeboid movement:
Ø Amoeboid movement is found in amoeba, a unicellular animal.
Ø Amoeba moves by producing pseudopodia, which are cytoplasmic projections. This involves changes in the shape of the cell body and streaming movement of cytoplasm into the pseudopodium.
Ø The movement due to pseudopodia in amoeba is termed as amoeboid movement.
Ø Amoeboid movement is the characteristic of certain cells in other organism. For example; the movement of WBC or leucocytes, in human blood.
Ø Amoeba moves about to obtain food or to avoid dangers or to escape from energy. Leucocytes like phagocyte or macrophages of the lymph, show amoeboid movements to engulf antigen or microbe and to immigrate in the circulatory food.
Ø Amoeboid movement found in amoeba, occurs in pseudopods where endoplasm flows forward and changes into ectoplasm.
2. Ciliary movement:
Ø Ciliary movement is the method by which ciliated protozoans like paramecium, move from one place to another place in water medium.
Ø Paramecium uses cilia not only for moving from one place to another place and also to derive water and food into their gullet.
Ø Coordinated cilia beat in a specific direction to move the organism.
Ø Ciliary movement occurs in most of our internal tubular organs which are ciliated epithelium.
Ø Passage of ova through the reproductive tract is also facilitated by ciliary movements.
Ø Cilia can perform a variety of function such as:
a. In certain molluscs, cilia help to pass water currents over the gills.
b. In echinoderms, cilia help to derive water through the water vascular system.
c. Cilia of the cells lining the respiratory tract of humans help to derive the microbes and dust particles away or towards the nose and mouth.
d. Cilia in the oviduct or fallopian tubes of human female transport ova.
3. Flagellar movement:
Ø Flagellum helps in the movement of certain protozoans like euglena.
Ø Flagellum is a long, thread like cytoplasmic projections.
Ø Flagella are larger than cilia and can also move organism by coordinated movement.
Ø Flagella in sperm help in the swimming movement.
4. Muscular movement:
Ø Muscular movement involves muscular contraction as a result of sliding of myofilaments within myofibrils.
Ø Muscular movement is the method used in most of the vertebrates like man.
Ø It involves the motor protein myosin, which forms cross bridges on actin fibers.
Ø Muscular movement is based on the use of muscle fibers.
Ø Muscle fibers have the unique ability to contract and relax, which exerts a force. This force is responsible for the movement of body parts and also aids in locomotion.
Ø The process of shortening is controlled by calcium ions released from the sarcoplasmic reticulum. The calcium ions bind to troponin; open myosin binding sites. In addition, there are three myosin binding site
Ø Different types of muscular system found in invertebrates include pedal locomotion, water vascular system, looping movement, walking, flight and jumping.
Ø Human movement and locomotion also results from co-operation between muscles and bones. Hence, study of both skeletal and muscular system in the human body becomes essential.
Role of muscles in locomotion:
· Muscles are mesodermal in origin.
· They have special properties like excitability, contractibility, extensibility and elasticity.
· Based on their locomotion, three types of muscles are identified.
A. Skeletal muscle:
Ø Skeletal muscles are closely associated with the skeletal components of the body.
Ø They have a striped appearance under the voluntary control of the nervous system, so they are known as voluntary muscles.
B. Visceral muscle:
Ø Visceral muscles are located in the inner wall of the hollow visceral organs of the body like alimentary canal, reproductive tract etc.
Ø They do not exhibit any striation and are smooth in appearance. Hence, they are called smooth muscles or non- striated muscles.
Ø Their activities are not under our control, so they are known as involuntary muscles.
Ø Flagellar movement helps in the swimming of spermatozoa, maintenance of water current in the canal system of sponges and in locomotion of protozoa like euglena.
C. Cardiac muscles:
Ø Cardiac muscles are the muscles of heart.
Ø They are striated muscles where number of striations or bands is present.
Ø These muscles are involuntary in nature as the nervous system does not control their activities directly.
Components of Muscle:
There are the components of muscles that help in the locomotory process. Such components are:
· Each organized skeletal muscles in our body is made up of a number of muscles bundles or fascicles held together by common collagenous connective tissue layer called fascia.
· Each muscle bundles contains a number of muscle fibers. Each muscle fibers is lined by the plasma membrane called sarcolemma enclosing the sarcoplasm.
· Muscle fibers are syncytium as the sarcoplasmic reticulum contains many nuclei.
· The endoplasmic reticulum i.e. sarcoplasmic reticulum of the muscle fibers is the store house of the calcium ions.
· Presence of large number of arranged filaments in the sarcoplasm called myofilaments or myofibrils; it is the characteristic feature of muscle fiber.
· Each myofibril has alternate arrangement of light and dark band.
· A myofibril has dark and light band.
· The dark bands are also called as A- band or anisotropic band.
· The light bands are known as I-band or isotropic band.
· At the center of A-band, a comparatively less dark zone called as H zone is present.
· Each I- band has its center where a dark membrane called Z line is present.
· The Z- line is also called as Z- disc or krause’s membrane or Doble’s line.
Skeletal system is made up of bones and cartilage. It is oftwo types; axial and appendicular skeleton. Skeletal system performs functions like;support, movement, protection,sexual dimorphism, mineral haemostasis.
Muscle cells are specialized for contraction which also helps in bodily processes such as respiration and digestion.Sarcomere must shortens for a muscle cell to contract.The sliding filament model defines the concept of muscle contraction.
Joints is a point of articulation where two or more bones meet. The motions like spin, swing, approximation and gliding movements are made possible by joints. Joints can be classified as fibrous, cartilaginous and synovial joints. Pivot and hinge joints are synovial joints.