Title LOCOMOTION AND MOVEMENT.pdf ✅

8 LOCOMOTION AND MOVEMENT SCAN CODE Locomotion and Movement LOCOMOTION AND MOVEMENT 20
LOCOMOTION AND MOVEMENT 9 SCAN CODE Locomotion and Movement Chapter 20 Locomotion and Movement 1. Introduction  Locomotion refers to the movement of an individual from one place to another.  It is difficult to differentiate between movement and locomotion because an animal cannot change its place (locomote) without movement. Thus movements are primarily connected to locomotion.  Movement is the most basic characteristic of living organisms. Non living objects do not move. If non living objects show movement, that is always due to some external force.  The movement of a non-living object is, therefore, induced (due to external force) while the movement of living things is automatic (self sustained).  Movements and locomotion cannot be studied separately. The two may be linked by stating that all locomotions are movements but all movements are not locomotions.  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. Types of Movements Cells of the human body exhibit three main types of movements, namely, amoeboid, ciliary and muscular. But flagellar movement is also found.  Amoeboid (Pseudopodial) Movement This type of movement is found in leucocytes (phagocytes and macrophages of the human lymphatic system). It is affected by pseudopodia formed by the streaming of protoplasm (as in Amoeba). Cytoskeletal elements like microfilaments are also involved in amoeboid movement.
LOCOMOTION AND MOVEMENT 10 SCAN CODE Locomotion and Movement Fig. 20.1 Amoeboid Movement of Macrophages  Ciliary Movement Cilia of the upper respiratory tract of humans keep the invading microbes and dust particles out. Whereas, the cilia of fallopian tube (oviducts) and vasa efferentia of human females and males, transport ova and spermatozoa, respectively. Fig. 20.2 Measles viruses and ciliated epithelium of respiratory tract  Muscular Movement This basic mechanism is used in the majority of vertebrates, including humans. The universal property of this mechanism is to exert a force by alternate contraction and relaxation. Movement of our limbs, jaws, tongue etc require muscular movements. The contractile property of muscles are effectively used for locomotion and other movements by human beings and the majority of multicellular organisms. Fig. 20.3 Muscular movement in human body
LOCOMOTION AND MOVEMENT 11 SCAN CODE Locomotion and Movement  Flagellar Movement Human sperms exhibit flagellar movement. The flagellum is a propulsion equipment for the movement of sperm towards ovum. Fig. 20.4 Flagellar Movement of human sperm 2. Muscles  Muscle is a specialised tissue of mesodermal origin. About 40-50 per cent of the body weight of a human adult is contributed by muscles.  They have special properties like excitability, contractility, extensibility and elasticity.  Muscles have been classified using different criteria, namely location, appearance and nature of regulation of their activities.  Based on their location, three types of muscles are identified 2.1 Types of Muscles Fig. 20.5 Different types of muscles Skeletal Muscles  Skeletal muscles are closely associated with the skeletal components of the body.  They are found in limbs, body wall, tongue, pharynx and beginning of oesophagus.  They have a striped appearance under the microscope and hence are called striated muscles.  As their activities are under the voluntary control of the nervous system, they are known as voluntary muscles too.  Potassium is the most abundant mineral element in muscles and other minerals such as calcium, sodium, phosphorus and magnesium are present only in traces.  Muscles store glycogen and also have oxygen carrying pigment myoglobin. They also contain ATP, phosphocreatine, creatine and urea etc.  They are primarily involved in locomotory actions and changes of body postures. Visceral or Smooth Muscles  Visceral muscles are located in the inner walls of hollow visceral organs of the body like the posterior part of oesophagus, stomach, intestine, lungs, urogenital tract, urinary bladder, blood vessels, iris of eyes, dermis of skin and arrector pili muscles.