Chapter 17: Locomotion and Movement

Biology • Class 11

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Chapter Analysis

Intermediate13 pages • English

Quick Summary

The chapter 'Locomotion and Movement' covers the movement mechanisms in animals and humans, emphasizing muscle contraction and the skeletal system. Muscle types such as skeletal, visceral, and cardiac are discussed, along with their structure and function in movement and locomotion. The skeletal system, including bones and joints, is detailed, highlighting their roles in providing a framework and enabling movement. Disorders associated with the muscular and skeletal systems, such as myasthenia gravis and arthritis, are also explained.

Key Topics

  • Muscle contraction
  • Types of muscles
  • Sliding filament theory
  • Skeletal system
  • Function of joints
  • Muscular disorders
  • Role of ATP in muscles
  • Distinctions between red and white fibers

Learning Objectives

  • Understand the structure and types of muscle tissue
  • Explain the mechanisms of muscle contraction
  • Identify components of the skeletal system
  • Describe the types and functions of joints
  • Recognize disorders related to muscular and skeletal systems
  • Analyze the roles of calcium ions and ATP in muscle function

Questions in Chapter

Draw the diagram of a sarcomere of skeletal muscle showing different regions.

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Define sliding filament theory of muscle contraction.

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Describe the important steps in muscle contraction.

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Write true or false. If false change the statement so that it is true. (a) Actin is present in thin filament (b) H-zone of striated muscle fibre represents both thick and thin filaments. (c) Human skeleton has 206 bones. (d) There are 11 pairs of ribs in man. (e) Sternum is present on the ventral side of the body.

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Write the difference between : (a) Actin and Myosin (b) Red and White muscles (c) Pectoral and Pelvic girdle

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Match Column I with Column II : Column I Column II (a) Smooth muscle (i) Myoglobin (b) Tropomyosin (ii) Thin filament (c) Red muscle (iii) Sutures (d) Skull (iv) Involuntary

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What are the different types of movements exhibited by the cells of human body?

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How do you distinguish between a skeletal muscle and a cardiac muscle?

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Name the type of joint between the following:- (a) atlas/axis (b) carpal/metacarpal of thumb (c) between phalanges (d) femur/acetabulum (e) between cranial bones (f) between pubic bones in the pelvic girdle

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Fill in the blank spaces: (a) All mammals (except a few) have __________ cervical vertebra. (b) The number of phalanges in each limb of human is __________

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Additional Practice Questions

Explain the role of the calcium ions in muscle contraction.

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Answer: Calcium ions play a crucial role in muscle contraction by binding to troponin, which causes a change in the conformation of tropomyosin, thus exposing the binding sites on actin filaments for the myosin heads.

What are the differences between aerobic and anaerobic muscle fibers?

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Answer: Aerobic muscle fibers, also known as red fibers, have high myoglobin content and many mitochondria, enabling sustained activity through aerobic respiration. Anaerobic fibers, or white fibers, have less myoglobin and mitochondria, relying more on anaerobic metabolism for short, intense bursts of activity.

Why are synovial joints crucial for movement?

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Answer: Synovial joints are crucial for movement as they allow significant mobility between bones due to their fluid-filled cavity, nearby supporting ligaments and tendons providing structure and strength.

Distinguish between the axial and appendicular skeleton.

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Answer: The axial skeleton consists of the skull, vertebral column, and rib cage, providing central support and protection for the brain and vital organs. The appendicular skeleton encompasses limbs and girdles, facilitating movement.

How do cardiac muscles differ from skeletal and visceral muscles in terms of structure and function?

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Answer: Cardiac muscles are striated, branched, and involuntary, possessing intercalated discs that allow for synchronized contractions. Unlike skeletal and visceral muscles, cardiac muscle cells are self-excitable and modulate heart contractions autonomously.