NCERT Class 11 Biology Chapter 20 Notes Locomotion And Movement- Download PDF Notes

The locomotion and movement chapter of the NCERT is very important from an exam point of view. The NCERT Class 11 Biology Chapter 20 notes give you a basic idea of the chapter locomotion and movement. The main topics covered in NCERT Class 11 Biology locomotion and movement notes are definition, types of movement, muscle, mechanism of muscle contraction, the skeletal system, joints, and disorders of the muscular and skeletal systems. Download the CBSE Notes for Class 11 Biology, Chapter 20, PDF to use offline anywhere. Students must go through each topic in the locomotion and movement in Class 11 Notes Biology in the easiest and most effective way possible with the help of NCERT Notes for Class 11.

Class 11 Biology chapter 20 notes also cover all the important concepts related to this chapter, which are useful in various competitive exams. Locomotion and Movement NCERT Notes for Class 11 Biology help you revise these major concepts given in the NCERT Book in a short period of time during CBSE Board exam preparation. CBSE Class 11 Biology Chapter 20 notes will help you with quick revision. The Locomotion and Movement chapter covers all headings of NCERT. CBSE Class 11 Biology chapter 20 notes also contain important examples that have been frequently asked in the various exams. Having revision notes and NCERT Solutions for Class 11 Biology Chapter 20 handy is beneficial to save you time.The NCERT Class 11 notes pdf can be downloaded through the link given below.

Also, Students can refer,

• NCERT Solutions for Class 11 Biology Chapter 20 Locomotion and Movement.
• NCERT Exemplar Class 11 Biology Chapter 20 Solutions Locomotion and Movement.

NCERT Class 11 Chapter 6 Class Notes

Locomotion and Movement

• Locomotion:- Movements result in a change of place or location. Such a type of voluntary Movement is called Locomotion.
• Walking, Running, Climbing, Swimming, Flying are types of Locomotory movements.
• Locomotion is generally performed by animals for the search of food, shelter, mate, Escape from predators, Favourable Climatic conditions.

Types of Movement

Amoeboid:

Amoeboid movement is exhibited by macrophages and leukocytes.

Ciliary:

• In this, movement occurs in most of our internal tubular organs. It is lined by ciliated epithelium.
• Coordinated movement of cilia in the trachea help in removing dust particle Inhaled with atmospheric air
• Passage of ova through the female reproductive tract

Muscular:

• Movement of our limbs, jaws, tongue, etc.

Flagellar movement helps in the swimming of Spermatozoa. It also maintains water current in the canal system of sponges and in the locomotion of Protozoans such as Euglena.

Muscle

• Mesodermal origin
• 40-50% of body weight
• Properties- Excitability, Contractility, Extensibility and Elasticity.

Types of Muscles:-

Skeletal muscles:

• Striated Muscles
• Voluntary Muscles
• Primarily involved in locomotory actions and change in body postures.

Visceral Muscles:

• Unstriped or non-striated Muscles
• Involuntary Muscles
• Found in Wall of hollow organ

Cardiac Muscles:

• Striated Muscles
• Involuntary Muscles
• Found in heart

Structure of Skeletal Muscle in Detail

• Made up of Muscles bundle or fascicles. Fascicles held together by Fascia

• Each muscle bundle made up of many muscles fibers

• Muscle fibres lined by a plasma membrane called Sarcolemma

• It is long, multinucleate, and unbranched.

• Muscle fibre contains the sarcoplasmic reticulum which is the house of Calcium ions.

• A Characteristic feature of muscle fibre is the presence of many parallelly arranged filaments presence in sarcoplasm called myofibrils.

• Each myofibril has alternate dark and light bands.

• Light band or isotropic band or I band contain Actin.

• Dark band or anisotropic band or A band contain Myosin.

• Z Line (elastic fibre) is present in the centre of each ‘I’ band and bisect it.

• M Line (thin fibrous membrane) is present in the middle of the ‘A’ band.

• The part of the myofibril between two successive ‘Z’ lines is the functional unit of Contraction and is called a sarcomere.

• The edges of thin filaments on either side of the thick filaments partially overlap.

• Central part of thick filament ,not overlapped by thin filament Called ‘H’ Zone

Structure Of Contractile Protein:-

• Each actin (thin) filament is made of two ‘F’ (filamentous) helically coiled to each other.

• ‘F’ actin is a polymer of ‘G’ (Globular) actins.

• Two filaments of tropomyosin protein also run close to ‘F’ actin throughout its length.

• On the tropomyosin, a complex protein Troponin is distributed at equal intervals.

• A subunit of troponin masks the active binding sites for Myosin on the actin filaments in the resting state.

• Each myosin (thick) filament is a polymerised protein as well.

Meromyosin:-

1. Heavy Meromyosin (HMM): A Globular head with a short arm

2. Light Meromyosin (LMM): Includes tail

• The binding site for ATP and ATPase Enzyme and actin present on Globular head.

Mechanism of Muscle Contraction:-

• Best explained by Sliding Filament Theory

• Thin filament slide over the thick filament

• Muscle contraction is initiated by the signal sent by the Central Nervous System(CNS)

• Neural signals reacting at neuromuscular junctions release neuro-transmitters which generate an action potential in Sarcolemma.

• Action potential spread by the Sarcolemma and releases calcium ions into the sarcoplasm.

• When the level of calcium ion increases, it leads to the binding of calcium with a subunit of Troponin on actin filament and then removing the masking of the active site for myosin to form a cross bridge.

• Actin filaments move towards the centre of the A band.

• Length of sarcomere decrease

• ‘I’ band reduces whereas ‘A’ band length remains the same.

• Myosin, releasing the ADP and P1 Goes back to its relaxed state.

Muscle Fatigue:-

• Repeated Activation of muscle can lead to accumulation of lactic acid due to anaerobic breakdown of glycogen causing muscle fatigue.

Types of Muscle Fibre:-

Red Muscle Fibre:-

• Myoglobin content is high.

• More mitochondria.

• Aerobic Muscle fibre

• Sarcoplasmic reticulum low

White Muscle fibre:-

• Myoglobin content low

• Less number of mitochondria

• Anaerobic Muscle fibre

• Sarcoplasmic reticulum high

Skeletal System

• Consists of a framework of bones and a few cartilages.

• The human endoskeleton consists of 206 bones: Axial skeleton- 80 bones, and Appendicular skeleton – 126 bones

Axial Skeleton:

• Consist of the Skull, Vertebral column, Sternum, and ribs

• Skull is made of Cranial and facial bone- 22 bones

• Cranial bones- 8 in number:- Frontal(1), Parietal(2), Occipital(1), Temporal(2), Sphenoid(1), Ethmoid(1).

• Facial bone- 14 in number: - Mandible(1), Maxilla(2), Palatine(2), Nasal(2), Vomer(1), Inferior turbinal(2), Zygomatic(2), Lacrimal(2).

• Each middle ear consists of three tiny bones Malleus, Incus, Stapes.

• Hyoid bone: Single U-shaped bone present at the base of buccal.

• Vertebral column: Cervical(7), Thoracic(12), Lumber(5), Sacral(1 fused), Coccygeal(1 fused).

• Sternum: Flat bone on midventral line of thorax.

Ribs- 12 Pairs

• 1st to 7th pair: True ribs(Vertebro sternal ribs)
• 8,9,10th pair: Vertebro- chondral ribs
• 11th,12th pairs: Vertebral ribs (Floating ribs)
• Thoracic Vertebrae, ribs, and Sternum form rib cage.

Appendicular Skeleton:

• The bone of limbs along with their girdles
• Fore limbs: 30 bones. Humerus, radius, ulna, Carpals(Wrist bone-8), Metacarpals(palm-5), Phalanges(digits-14)
• Hind limbs: 30 bones. Femur, Patella, Tibia, Fibula, Tarsals(Ankle-7),Metatarsals(sole-5),Phalanges(digit-14)
• Femur: Longest bone of the body
• Pectoral Girdle: Made Up of clavicle (Collar bone) and scapula bones
• Pelvic Girdle: Consist of two coxal bones.
• Each coxal bone is formed by the fusion of ilium, ischium, and pubis.

Joints

Fibrous Joint: Do not allow any movement eg. Sutures(Between Skull bone)

Cartilaginous joint: Bone involve are joined together with help of cartilage eg. Pubic symphysis, Intervertebral disc

Synovial joint: Presence of fluid-filled synovial cavity between articulating surface of two bones. Eg. Ball and socket, Hinge, Pivot, Gliding, and saddle joint

Disorders of The Skeletal System

• Arthritis: Inflammation of joints

• Osteoporosis: Bone mass decreases and bone becomes weak.

• Gout: Inflammation Of joint due to accumulation of Uric acid crystals.

Chapter-Wise NCERT Class 11 Notes Biology

Significance of NCERT Notes for Class 11 Biology Chapter 20:

Class 11 Locomotion and Movement Notes will be helpful to revise the chapter. These Notes for Class 11 Biology Chapter 20 are also beneficial for covering the core concepts of the CBSE Biology Syllabus in Class 11 as well as for competitive exams such as AIPMT, AIIMS, NEET, and other similar exams. Class 11 Biology chapter 20 notes pdf download can be utilized for offline preparation.

Subject Wise NCERT Exemplar Solutions

• NCERT Exemplar Class 11 Solutions
• NCERT Exemplar Class 11 Maths
• NCERT Exemplar Class 11 Physics
• NCERT Exemplar Class 11 Chemistry
• NCERT Exemplar Class 11 Biology

Subject Wise NCERT Solutions

• NCERT Solutions for Class 11 Mathematics
• NCERT Solutions for Class 11 Chemistry
• NCERT Solutions for Class 11 Physics

• NCERT Solutions for Class 11 Biology