Class 11 Biology Chapter 17 Locomotion and Movement – Revision Notes

Movement in animals relies on muscles and a skeletal framework working together, and this chapter breaks down the sliding filament theory alongside the axial and appendicular divisions of the human skeleton.

Last Updated: September 23, 2026

Movement Types

• Amoeboid, ciliary, muscular.

Muscle Types

• Skeletal (voluntary, striated), smooth (involuntary), cardiac (involuntary, striated).

Sliding Filament Theory

• Sarcomere; actin/myosin cross-bridges; requires Ca²⁺ + ATP; troponin/tropomyosin regulate.

Skeleton

• 206 bones: axial (80) + appendicular (126).
• Joints: fibrous (immovable), cartilaginous (slight), synovial (freely movable).

One-Line Summary

Locomotion and movement are enabled by the coordinated action of the skeletal and muscular systems, with muscle contraction driven by the ATP- and calcium-dependent sliding of actin and myosin filaments within sarcomeres.

Frequently Asked Questions

What is the difference between locomotion and movement as defined in this chapter?
Movement refers to any change in the position of a body part, such as the beating of cilia or the flow of blood, while locomotion specifically refers to movement that results in a change of location of the entire organism.

How do muscles and bones work together to produce movement?
Muscles are attached to bones through tendons, and when a muscle contracts, it pulls on the bone it is attached to, causing movement at a joint, while the antagonistic muscle relaxes.

Written by Satish

NCERTBooks.org is an independent educational resource run by a small team focused on making official NCERT textbooks easy to find, read, and download for students, parents, and teachers across India. We are not affiliated with NCERT or the Ministry of Education -- we organise publicly available NCERT content by class and subject, verify links against official sources, and build tools (like our in-browser reader) that make studying more convenient. Every guide we publish is written and reviewed by our team based on the actual NCERT curriculum and syllabus.