Locomotion and Movement NEET 2025 PDF

LOCOMOTION AND MOVEMENT 1 MOVEMENT AND LOCOMOTION 2 TYPES OF MOVEMENT / LOCOMOTION Movement Significant feature of living beings....

LOCOMOTION AND MOVEMENT 1 MOVEMENT AND LOCOMOTION 2 TYPES OF MOVEMENT / LOCOMOTION Movement Significant feature of living beings. Type Structure Examples and functions Locomotion Voluntary movements resulting in change in place/location. Pseudopodia involve Locomotion is performed by organisms for variable reasons, e.g.. microfilaments Amoeboid and streaming of Leucocytes, macrophages, Amoeba Their habitats. protopalsm Demand of situation like search of food, mate, breeding ground, escape from enemies/predators. Removing dust particles from trachea Ciliary Cilia Passage of ova through female reproductive tract 2 MUSCLES Maintenance of water current in canal system of sponges Muscle tissue: Mesodermal in origin Flagellar Flagella Locomotion in Euglena 40-50% of body weight of a human adult is contributed by muscles. Swimming of spermatozoa Properties. Excitability Contractility Extensibility Elasticity Movement of Limbs, jaws, tongue Many cardiac muscle cells assemble in branching pattern Muscular Muscles to form a cardiac muscle Running, walking, climbing, flying Basis Locationt Appearance Regulation Example All locomotions are movements but all movements are not locomotion. Skeletal Striated Voluntary Muscles of limbs Classification Visceral Non-striated/ Involuntary Inner walls of In Paramoecium - Cilia helps in movement of food through cytopharynx of Muscles Cardiac smooth visceral organs and in locomotion as well. Involuntary Striated Muscles of In Hydra - Tentacles are used for capturing or prey & also for locomotion. heart Locomotion requires a perfect coordinated activity of muscular, skeletal and neural systems. 4 SKELETAL MUSCLE FIBRES & ITS TYPES Skeletal muscles are closely associated with the skeletal components of the body Sarcolemma Muscle fibre Blood capillary (muscle cell) Skeletal muscle Many Sarcolemma (Plasma membrane) Muscle fibre bundles/ Fascicles Sarcoplasm (cytoplasm) Many muscle Held by Nucleus (syncitum) fibres Fascia (collagenous Sarcoplasmic reticulum (store Cao) connective tissue) Fascicle (muscle bundle) Types Red White Each muscle fibre have many parallelly Myoglobin arranged myofibrils/myofilaments. Muscle fibre: Anatomical unit of muscle. Mitochondria Skeletal muscles are primarily involved in locomotion and change in body posture. SR Respiration Mainly Mainly aerobic anaerobic  5 MYOFILAMENTS AND STRUCTURE OF CONTRACTILE PROTEINS Each myofibril has dark and light bands due to actin and myosin distribution that establish striated appearance. Filament Held by Protein Monomer Polymer Typical Z-line Actin Filamentous Globular F-actin helically arranged Troponin (bisect (contractile Thin/actin 'G’-actin Tropomyosin run close to I-band) Tropomyosin F-actin throughout its length Tropomyosin (2 stands) Troponin distributed at regular intervals on 3 tropomyosin. Troponin Mask active binding sites F-actin (2 stands) for myosin. M-line Meromyosin HMM -Head Project outward at regular Myosin (thin fibrous (MM) (Heavy)- Short arm distance and angle from (contractile) Thick membrane) each other from the surface of polymerised LMM – Tail myosin filament and is (Light) known as cross arm. 6 MECHANISM OF MUSCLE CONTRACTION/SLIDING FILAMENT THEORY Contraction of muscle fiber takes place by the sliding of thin filaments over the thick filaments. A motor neuron along with the muscle fibres connected to it constitute a motor unit. CNS via Motor neuron Neurotransmitter Acetylcholine At Neuromuscular Junction/Motor end plate, action potential is generated in sarcolemma that causes release of Ca2+ in sarcoplasm from SR leading to Ca2+ increase in sarcoplasm Ca2+ binds to troponin subunit, change in its confirmation, unmask active site for myosin binding on actin filament Energised myosin (Myosin – ADP + Pi) binds to actin Cross bridge = Actin-myosin-ADP + Pi Result Pull thin filaments toward centre Shortening Pull Z-line contraction Length of I-band reduced of sarcomere Length of A-band retained ADP + Pi released from myosin head New ATP binds to myosin head Cross bridge broken ATP hydrolysis on myosin head Cycle repeats Process will continue till Ca2+ pumped back to sarcoplasmic cisternae Z-line return to original position Reaction time of fibres vary in different muscles Globular head is active ATPase enzyme and has binding sites for ATP and active sites for actin. Repeated activity of muscle leads to accumulation of lactic Thin filaments make I/Isotropic band-actin acid due to anaerobic breakdown of glycogen in them, causing fatigue. Thick filaments make A/Anisotropic band – actin + myosin  Sarcomere: Functional unit of contraction between 2-Z lines (elastic fibres) H-zone is non overlapped part of thick filament by thin filaments. Arranged alternately throughout the length of myofibrils parallel to each other and to longitudinal axis of myofibrils 7 SKELETAL SYSTEM This system has significant role in movement shown by the body. Axial skeleton (Bones-80). Framework of 206 bones & few cartilages. Bones distributed along main axis. Principle division Appendicular skeleton Axial skeleton. Bones No. Structure Name of bones Typical feature or basic function Included SKULL 1-Frontal 1-Occipital Protect brain Cranium 8 2-Parietal 1-Ethmoid Articulates with superior region of vertebral column by 2 2-Temporal 1-Sphenoid occipital condyles (Dicondylic skull) 2-Nasal 1-Mandible Facial 14 2-Lacrimal 2-Maxilla Form front part of skull 2-Zygomatic 5-others Hyoid 1 1-U-shaped Present at the base of buccal cavity 2-Malleus Ear 6 2-Incus Present in the middle ear Ossicles 2-Stapes VERTEBRAL COLUMN 7-Cervical Main framework of trunk Dorsal 12-Thoracic Protects spinal cord Vertebra (serially 26 5-Lumbar Supports head arranged units) 1-Sacral-Fused Point of attachment of ribs and muscles of back 1-Coccygeal-Fused 1" vertebra is atlas that articulates with occipital condyles Seven cervical vertebrae exist in almost all mammals. Neural canal of vertebrae - site STERNUM Chest bone 1 1-Flat bone On ventral, midline of thorax 14-Vertebrosternal Attach dorsally to vertebrae and ventrally True ribs to sternum with hyaline cartilage 24 6-Vertebrochondral False ribs RIBS Not directly attached to sternum but to 7th rib with Floating ribs 4-Vertebral hyaline cartilage (8th to 10th pair) Not connected ventrally (11th and 12th pair) All ribs are bicephalic thin flat bones i.e., they have 2 articulating ends on dorsal side Vertebral column + Sternum + Ribs = Rib Cage 8 APPENOICULAR SKELETON(BONES · 126) Consists of bones of limbs (30 × 4 = 120) and girdles (6) Pectoral girdle Pelvic girdle & upper arm & lower arm  Girdles helps in the articulation of limbs with axial skeleton Acetabulum, formed by fusion of ilium, ischium and pubis, articulates with femur to form hip joint Scapula, a dorsal triangular flat bone, have elevated ridge/spine expanded to form acromion process that articulates with clavicle 2 halves of pelvic girdle meet ventrally to form pubic symphysis containing fibrous cartilage Glenoid cavity in scapula articulates with humerus head to form shoulder joint 9 JOINTS They are essential for all types of movements involving bony parts of the body. Force generated by muscle is used to carry out movement through joint, where joint acts as fulcrum. Point of contact between bones or bones and cartilages. Types of joints (Basis - Major structural forms). TYPES BONES JOINED BY MOVEMENT EXAMPLES Fibrous Dense fibrous Do not allow Flat skull bones fused connective tissue any movement end to end via sutures to form cranium Cartilaginous Fibrous cartilage Limited movement Adjacent vertebrae Considerable Humerus & pectoral Synovial Fluid filled synovial movement, helps girdle (Ball and socket joint) cavity between in locomotion Knee joint (Hinge joint) 2 bones and many other Atlas & axis (Pivot joint) movements Between carpals (Gliding joint) Carpal & metacarpal of thumb (Saddle joint)  10 DISORDERS DISEASE CAUSES IMPACT Affect neuromuscular junction Fibrous Autoimmunity Fatigue, weakening and paralysis of skeletal muscles Progressive degeneration Muscular dystrophy Genetic of skeletal muscles Rapid spasms in muscle Tetany Low Ca2+ in body fluid (wild contractions) Arthritis Inflammation of joints Gout Accumulation of uric Inflammation of joints acid crystals Osteoporosis Age related Decreased bone mass Decreased levels of estrogen increased chances of fracture