What went wrong when the king rode under the arch?

It was too low and knocked off his crown

How does the chain of blame unfold in the poem?

Each accused person blames another, ending with the king's own changes

What are the three types of movement shown by human cells?

Amoeboid movement, ciliary movement and muscular movement.

Name the three types of muscle and their nature.

Skeletal muscle (striated, voluntary), visceral or smooth muscle (non-striated, involuntary) and cardiac muscle (striated, involuntary).

Define the sliding filament theory of muscle contraction.

It states that contraction of a muscle fibre takes place by the sliding of the thin actin filaments over the thick myosin filaments, shortening the sarcomere.

Describe the important steps in muscle contraction.

A nerve impulse releases acetylcholine and then calcium, which exposes the actin binding sites; myosin heads form cross bridges, pull the actin filaments inward using ATP, and the sarcomere shortens, with relaxation when calcium is pumped back.

What happens to the I band and A band during contraction?

During contraction the I bands shorten while the A bands retain their length.

Differentiate between red and white muscle fibres.

Red fibres are rich in myoglobin and mitochondria and are aerobic, while white fibres have little myoglobin, fewer mitochondria and depend on anaerobic respiration.

How many bones are there in the human skeleton and how are they grouped?

There are 206 bones, grouped into the axial skeleton (80 bones) and the appendicular skeleton.

Name the bones of the human skull.

The skull has 22 bones, 8 cranial bones forming the cranium and 14 facial bones, along with the hyoid and the ear ossicles.

Name the three types of joints with examples.

Fibrous joints (skull sutures), cartilaginous joints (between vertebrae) and synovial joints (knee, shoulder).

Name two disorders of the muscular or skeletal system.

Osteoporosis, an age-related decrease in bone mass, and arthritis, inflammation of joints; others include tetany, gout and muscular dystrophy.

Locomotion and Movement

Class 11 Biology · Biology · Chapter 17

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CBSE Class 11 · Biology

19 chapters: every table, cycle and pathway

Marks booster + cheatsheet: key concepts in 2 lines each, common traps
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CBSE Class 11 · Biology

19 chapters: every table, cycle and pathway

Marks booster + cheatsheet: key concepts in 2 lines each, common traps
18 marks: Unit V, breathing to hormones
15 marks each: Units I and III
Common traps, corrected
Five kingdoms classification table
Physiological numbers, with page numbers

Page 1 free about 8 min read, Full kit about 55 min read

₹159See the full kit

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Summary

This chapter studies the types of movement in the human body and the muscular and skeletal systems that make locomotion possible. Cells show amoeboid, ciliary and muscular movements; locomotion is a voluntary movement that changes the location of the animal. Muscle is a tissue of mesodermal origin with the properties of excitability, contractility, extensibility and elasticity, classified by location into skeletal (striated, voluntary), visceral (smooth, involuntary) and cardiac muscle. A skeletal muscle is made of bundles of muscle fibres, each containing myofibrils with sarcomeres, the functional units bounded by Z lines and made of thin actin and thick myosin filaments. According to the sliding filament theory, contraction occurs when the thin filaments slide over the thick filaments: a nerve signal releases calcium, which exposes binding sites so that myosin heads form cross bridges and pull the actin filaments inward, shortening the sarcomere. Muscles may be red (aerobic, with myoglobin) or white (anaerobic). The skeletal system has 206 bones grouped into the axial skeleton (skull, vertebral column, ribs, sternum) and the appendicular skeleton (limb bones and girdles). Joints, the points of contact between bones, are fibrous, cartilaginous or synovial, the last allowing free movement. Disorders include myasthenia gravis, muscular dystrophy, tetany, arthritis, osteoporosis and gout.

Types of movement and locomotionTypes and structure of muscleContractile proteins and the sarcomereSliding filament theory of contractionAxial and appendicular skeletonJoints and skeletal-muscular disorders

Key terms

Locomotion

A voluntary movement that causes an animal to change its place or location.

Sarcomere

The functional unit of contraction in a myofibril, the part between two successive Z lines.

Sliding filament theory

The theory that muscle contraction occurs by the sliding of thin actin filaments over thick myosin filaments.

Axial skeleton

The 80 bones along the main axis of the body: skull, vertebral column, sternum and ribs.

Appendicular skeleton

The bones of the limbs and the pectoral and pelvic girdles.

Synovial joint

A freely movable joint with a fluid-filled synovial cavity between the articulating bones.

Extra questions & answers

Try one from this chapter

A voluntary movement that causes an animal to change its place is called:

Flashcards & interactive practice