Bihar Board - Class 11 biology - Chapter 20: Locomotion and Movement Handwritten Notes

Movement is a fundamental characteristic of living organisms, enabling them to perform vital functions such as finding food, escaping predators, and reproducing. Locomotion refers to the movement of an organism from one place to another. This chapter define the type of movement, and the human skeletal and their muscular systems.

Key Points

1. Types of Movement

   • Amoeboid Movement: Movement through pseudopodia, seen in amoeba and certain human cells like white blood cells.
   • Ciliary Movement: Performed by cilia, such as in the respiratory tract and oviducts.
   • Muscular Movement: Involves muscle contraction, enabling movement of body parts and locomotion.

2. Skeletal System

   • Axial Skeleton: Includes the skull, vertebral column, ribs, and sternum, providing support and protection to vital organs.
   • Appendicular Skeleton: Includes the bones of limbs, girdles (pectoral and pelvic), facilitating movement and locomotion.
   • Joints: Points where two or more bones meet, allowing movement. Types include:
     • Ball and Socket Joint: Shoulder and hip joints.
     • Hinge Joint: Elbow and knee.
     • Pivot Joint: Between the first two vertebrae of the neck.

3. Muscular System

   • Types of Muscles:
     • Skeletal Muscles: Striated and voluntary, attached to bones for locomotion.
     • Smooth Muscles: Non-striated and involuntary, found in internal organs.
     • Cardiac Muscles: Striated and involuntary, found in the heart.
   • Muscle Contraction:
     • Follows the sliding filament theory, where actin and myosin filaments slide past each other using ATP.
     • Regulated by calcium ions and nerve impulses.

4. Mechanism of Locomotion in Humans

   • Bones and Muscles: Work together to produce movement through contraction and relaxation of muscles.
   • Gait and Posture: Coordinated action of skeletal muscles maintains posture and facilitates walking, running, and other movements.

5. Disorders of the Musculoskeletal System

   • Arthritis: Inflammation of joints, causing pain and stiffness.
   • Osteoporosis: Reduction in bone density, leading to fragile bones.
   • Muscular Dystrophy: A genetic disorder causing progressive muscle weakness.
   • Sprains and Fractures: Injuries affecting ligaments and bones, respectively.

6. Locomotion in Animals

   • Different modes of locomotion, such as swimming in fish, flying in birds, and crawling in earthworms, are adapted to specific environments and lifestyles.

Conclusion

Locomotion and movement are vital for the survival and functioning of organisms. The human skeletal and muscular systems work in harmony to enable movement, provide structure, and protect vital organs. Understanding these systems helps in maintaining physical health and addressing related disorders effectively.

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