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Locomotion and Movement

NCERT Class 11 Biology Chapter 17

Locomotion and Movement for Class 11 Biology and NEET: types of movement, muscle structure and contraction, the human skeleton, joints and disorders.

5 topics Updated 8 Nov 2026

For: Class 11 and NEET

In the syllabus: NEET Class 11 syllabus

With your textbook

NCERT Biology (Class 11), Chapter 17 “Locomotion and Movement”, reprint 2026-27.

Open the official NCERT chapter (PDF, 4.5 MB, ncert.nic.in)

Checked on 19 Oct 2026.

Learn in this order

  1. Types of movement: amoeboid, ciliary, muscular

    The difference between movement and locomotion, and amoeboid, ciliary, flagellar and muscular movement.

    NCERT Section 17.1 8 min read 3 solved examples 6 practice questions

  2. Muscle: structure and mechanism of contraction

    a labelled sarcomere diagram, actin, myosin and troponin, the sliding filament theory, and red and white fibres.

    NCERT Section 17.2 19 min read 7 solved examples 7 practice questions

  3. Human skeletal system: axial and appendicular

    Axial vs appendicular skeleton, 206 bones, skull, vertebrae, true, false and floating ribs, limbs and girdles.

    NCERT Section 17.3 12 min read 5 solved examples 6 practice questions

  4. Joints: fibrous, cartilaginous and synovial

    Fibrous, cartilaginous and synovial, and ball and socket, hinge, pivot, gliding and saddle joints with examples.

    NCERT Section 17.4 9 min read 3 solved examples 6 practice questions

  5. Disorders of the muscular and skeletal system

    Causes of myasthenia gravis, muscular dystrophy, tetany, arthritis, osteoporosis, gout.

    NCERT Section 17.5 9 min read 3 solved examples 6 practice questions

Key formulas in this chapter

Types of movement

  • locomotion ⊂ movement
  • amoeboid: pseudopodia (macrophages, leucocytes)
  • ciliary: trachea, female reproductive tract
  • flagellar: sperms, sponges, euglenoids
  • muscular: limbs, jaws, tongue

Muscle and muscle contraction

  • sarcomere: Z line → Z line (functional unit)
  • shortening: I band and H zone shorten; A band unchanged
  • thin filament: 2 F-actin + tropomyosin + troponin
  • NCERT myosin regions: head + short arm (HMM), tail (LMM)
  • trigger: acetylcholine → Ca → troponin → cross bridge

Skeletal system

  • 206 = axial 80 + appendicular 126
  • skull 22 = 8 cranial + 14 facial
  • adult vertebral-column bones 26 = 7 + 12 + 5 + 1 + 1
  • ribs: 7 true + 3 false + 2 floating = 12 pairs
  • each limb = 30 bones

Joints

  • fibrous: dense fibrous connective tissue; no movement (skull sutures)
  • cartilaginous: adjacent vertebrae, limited movement
  • synovial: considerable movement (fluid-filled cavity)
  • ball and socket: humerus–pectoral girdle; hinge: knee
  • pivot: atlas–axis; gliding: carpals; saddle: thumb carpal–metacarpal

Disorders of muscles and bones

  • myasthenia gravis: autoimmune, neuromuscular junction
  • muscular dystrophy: genetic, progressive
  • tetany: low Ca → spasms
  • gout: monosodium urate crystals (NCERT: uric acid)
  • osteoporosis: reduced bone strength; increased fracture risk

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