Locomotion and Movement

• Movement is a significant feature of living beings, with animals and plants exhibiting a wide range of movements.
• Streaming of protoplasm in the unicellular organisms like Amoeba is a simple form of movement.
• Movement of cilia, flagella and tentacles are shown by many organisms.
• The sarcomere of skeletal muscle consists of different regions.
• The sliding filament theory of muscle contraction explains the mechanism of muscle contraction.
• Synovial joints allow considerable movements and therefore, play a significant role in locomotion.
• The important steps in muscle contraction are: activation, shortening, and relaxation.
• Human beings can move limbs, jaws, eyelids, tongue, etc.
• Some of the movements result in a change of place or location, these voluntary movements are called locomotion.
• Walking, running, climbing, flying, swimming are all some forms of locomotory movements.
• Locomotory structures need not be different from those affecting other types of movements, for example, in Paramoecium, 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.
• We use limbs for changes in body postures and locomotion as well, suggesting that movements and locomotion cannot be studied separately.
• 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, but locomotion is generally for search of food, shelter, mate, suitable breeding grounds, favourable climatic conditions or to escape from enemies/predators.
• Cells of the human body exhibit three main types of movements, namely, amoeboid, ciliary and muscular.
• Some specialised cells in our body like macrophages and leucocytes in blood exhibit amoeboid movement, effected by pseudopodia formed by the streaming of protoplasm (as in Amoeba).
• Cytoskeletal elements like microfilaments are also involved in amoeboid movement.
• Ciliary movement occurs in most of our internal tubular organs which are lined by ciliated epithelium, facilitating the passage of ova through the female reproductive tract and removal of dust particles in the respiratory system.
• Movement of our limbs, jaws, tongue, etc, require muscular movement, which is effected by the contractile property of muscles.
• Locomotion requires a perfect coordinated activity of muscular, skeletal and neural systems.
• Muscle is a specialised tissue of mesodermal origin, contributing about 40-50 per cent of the body weight of a human adult, with 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.
• Joints have been classified into three major structural forms, namely, fibrous, cartilaginous and synovial.
• Below the acromion is a depression called the glenoid cavity which articulates with the head of the humerus to form the shoulder joint.
• Each coxal bone is formed by the fusion of three bones – ilium, ischium and pubis.
• These are called vertebrochondral (false) ribs.
• The bones of the hand (fore limb) are Cervical vertebra, Intervertebral disc, Sacrum, Coccyx, Thoracic vertebra, Lumbar vertebra.
• Thoracic vertebrae, ribs and sternum together form the rib cage.
• The last 2 pairs of ribs, 11th and 12th, are not connected ventrally and are therefore, called floating ribs.
• The movability at these joints vary depending on different factors.
• The bones of the limbs along with their girdles constitute the appendicular skeleton.
• Force generated by the muscles is used to carry out movement through joints, where the joint acts as a fulcrum.
• Pelvic girdle consists of two coxal bones.
• The dorsal, flat, triangular body of scapula has a slightly elevated ridge called the spine which projects as a flat, expanded process called the acromion.
• The two halves of the pelvic girdle meet ventrally to form the pubic symphysis containing fibrous cartilage.
• Each limb is made of 30 bones.
• This bone is commonly called the collar bone.
• The clavicle articulates with this.
• Fibrous joints do not allow any movement and are represented