# Locomotion and Movement Notes, Class 11 Biology | SwaVid Locomotion and Movement, NCERT Class 11 Biology: notes with key ideas, key terms, common mistakes and 3 quick checks with worked answers. Canonical: https://www.swavid.com/cbse/class-11/biology/chapter/locomotion-and-movement Source: https://www.swavid.com/cbse/class-11/biology/chapter/locomotion-and-movement # Locomotion and Movement ## Key terms ## Key ideas ## Common mistakes ## Quick checks ## Keep going ## Questions parents ask ## Class 11 Biology on SwaVid ### Types of movement ### Structure of contractile proteins ### Mechanism of muscle contraction ### Axial skeleton ### Appendicular skeleton ### Joints and disorders ### Next chapter ### Related chapter ### All chapters SwaVid › CBSE › Class 11 › Biology › Locomotion and Movement Notes written by SwaVid from the NCERT textbook. Class 11 Biology, Chapter 17. Key ideas, formulas and common mistakes. CBSE prints 18 marks for Unit V, not for this chapter alone. Short answer. This chapter explains the types of movements in humans, the structure of skeletal muscle, and the mechanism of muscle contraction. It also details the human skeletal system, joints, and associated musculoskeletal disorders. Source: NCERT Biology (Reprint 2026-27) , Chapter 17, Locomotion and Movement Cells of the human body exhibit amoeboid, ciliary, and muscular movement. Amoeboid movement occurs in macrophages and leucocytes using pseudopodia, ciliary movement occurs in the respiratory tract and reproductive tracts, and muscular movement moves limbs, jaws, and the tongue. Each actin filament consists of two filamentous F-actins helically wound together, along with tropomyosin and troponin. Each myosin filament is composed of multiple meromyosin units, each having a heavy meromyosin globular head with an active ATPase site and a light meromyosin tail. Muscle contraction initiates with a neural signal at the neuromuscular junction releasing acetylcholine, causing action potentials and calcium ion release from the sarcoplasmic reticulum. Calcium binds to troponin to expose myosin binding sites on actin, allowing cross-bridge cycling and pulling of actin filaments toward the centre of the A band. The human skeletal system has 206 bones divided into axial and appendicular divisions. The axial skeleton has 80 bones consisting of the skull, vertebral column, sternum, and 12 pairs of ribs. The appendicular skeleton has 126 bones comprising the pectoral and pelvic girdles and the bones of the limbs. Each limb contains 30 bones designed for locomotion and handling objects. Joints are classified structurally into fibrous, cartilaginous, and synovial joints. Common disorders include myasthenia gravis, muscular dystrophy, tetany, arthritis, osteoporosis, and gout. Try each question first. Then tap it to see the answer. Each human limb consists of 30 bones. Bones per forelimb: humerus (1), radius and ulna (2), carpals (8), metacarpals (5), phalanges (14) = 30. Total for both forelimbs = 30 × 2. 60 bones Thin filaments slide inwards towards the M line over thick filaments. A band retains its original length because thick filaments do not shorten. I band shortens and H zone reduces or completely disappears. A band remains unchanged; I band shortens; H zone reduces or disappears Rapid muscle spasms occur when calcium in body fluid drops significantly. NCERT defines rapid spasms in muscle due to low Ca²⁺ in body fluid as tetany. Tetany Neural Control and Coordination . Chemical Coordination and Integration . The 19 chapters of Class 11 Biology . CBSE does not give marks to one chapter. It prints 18 marks for Unit V, Human Physiology, which includes Locomotion and Movement. No. They are written by SwaVid from the NCERT textbook. The CBSE curriculum is the reference for what is assessed. Neural Control and Coordination. SwaVid is an AI tutor for Indian students in Classes 6 to 12. It finds the earlier ideas a child missed, then teaches today’s chapter. Start free to see how it works. - Ch 17 NCERT book - 18 marks, Unit V - 3 quick checks - Believing that the A band shortens during muscle contraction . Remember that the length of the thick filaments does not change. Only the I band and the H zone shorten or disappear as thin filaments slide inwards. - Confusing troponin and tropomyosin functions . A subunit of troponin masks the active binding sites for myosin on the actin filaments in the resting state. Calcium binds to troponin to remove this masking. - Mixing up tetany with tetanus . Tetany is caused by low calcium levels in body fluids leading to wild muscle contractions, whereas tetanus is an infectious disease caused by Clostridium tetani. - Counting floating ribs as part of true or false vertebrochondral ribs . Floating ribs are pairs 11 and 12 which remain completely unattached ventrally to the sternum or costal cartilage. ## Key Links - [CBSE](https://www.swavid.com/cbse) - [Class 11](https://www.swavid.com/cbse/class-11) - [Biology](https://www.swavid.com/cbse/class-11/biology/chapters) - [Start free →](https://www.swavid.com/signup) - [All 19 chapters](https://www.swavid.com/cbse/class-11/biology/chapters) - [NCERT Biology (Reprint 2026-27)](https://ncert.nic.in/textbook.php) - [Open notes](https://www.swavid.com/cbse/class-11/biology/chapter/neural-control-and-coordination) - [Open notes](https://www.swavid.com/cbse/class-11/biology/chapter/chemical-coordination-and-integration) - [Class 11 Biology](https://www.swavid.com/cbse/class-11/biology/chapters) - [Start free →](https://www.swavid.com/signup)