Locomotion And Movement Class 11 Notes Biology Chapter 20 - CBSE
Chapter : 20
What Are Locomotion And Movement ?
Types Of Movement
Ciliary Movement
- By cilia
- Ex- trachea and oviducts
Muscular movement
- By muscles
- Ex- limbs
Flagellar Movement
- By flagella
- Ex- Spermatozoa, sponges, Protozoa
Types Of Muscles
Skeletal Muscles
- Attached to skeleton
- Striations present
- Voluntary
- Rich blood supply
- Fatigue muscle
- Multinucleate
- More mitochondria
Visceral Muscles
- In visceral organs
- Striations absent
- Involuntary
- Poor blood supply
- Non-fatigue
- Uninucleate
- Less mitochondria
Cardiac Muscles
- In heart wall
- Striations present
- Involuntary
- Rich blood supply
- Non-fatigue
- Uninucleate
- Poor mitochondria
Skeleton Muscles
- Skeletal Muscle is made up of muscles bundles (fascicles), held together by collagenous connective tissue called fascia.
- Each muscle fibre has an alternate light and dark band, which contains a special contractile protein, called actin and myosin respectively. Actin is a thin contractile protein present in the light band and is known as the I-band, whereas myosin is a thick contractile protein present in the dark band and is known as the A-band. There is an elastic fibre called z line that bisects each I-band. The thin filament is firmly anchored to the z line. The central part of the thick filament that is not overlapped by the thin filament is known as the H-zone.
Contractile Protein And Muscle Contraction
- Actin (Thin) Filament: Each actin (thin) filament is made up of two F (filamentous) actins helically wound to each other. Each F actin is a polymer of monomeric G (Globular) actins. Two filaments of another protein, tropomyosin also run close to the ‘F’ actins throughout its length. A complex protein Troponin is distributed at regular intervals on the tropomyosin. In the resting state a subunit of troponin masks the active binding sites for myosin on the actin filaments.
- Myosin (Thick) Filament: Each myosin (thick) filament is also a polymerised protein. Actin binding sites ATP binding sites Head Cross arm Tail Myosin monomer (Meromyosin). Many monomeric proteins called Meromyosins constitute one thick filament. Each meromyosin has two important parts, a globular head with
a short arm and a tail, the former being called the heavy Meromyosin (HMM) and the latter, the Light meromyosin (LMM).
Skeleton System And Its Functions
Axial Skeletal System (80 BONES)
- Skull (29 BONES):
- Cranial bones (8): Frontal (1), Parietals (2), Temporals (2), Occipital (1), Sphenoid (1) and Ethmoid (1).
- Facial bones (14): Nasals (2), Maxillae (2), Zygomatics (2), Lacrimals (2), Palatines (2), Inferior nasals (2), Mandible (1) and Vomer (1).
- Hyoid bone (1): U-shaped bone seen below buccal cavity.
- Ear ossicles (3 x 2 = 6): Malleus (2), Incus (2) and stapes (2).
- Vertebral column (26 BONES): Cervical vertebrae (7), Thoracic vertebrae (12), Lumbar vertebrae (5), Sacral vertebrae (1-fused) and Coccygeal vertebrae (1-fused)
- Sternum or breast bone (1)
- Ribs (12 pairs): True ribs (first 7 pairs), false ribs (8th, 9th & 10th pairs).
Appendicular Skeletal System (126 BONES)
- Bones of forelimbs (30 x 2 = 60): Humerus (1), Radius (1), Ulna (1), Carpals (wrist bones- 8), Metacarpals
(palm bones-5) and Phalanges (digits-14). - Bones of hindlimbs (30 x 2 = 60): Femur (thigh bone- 1), Patella (knee cap- 1), Tibia (1) and fibula (1), Tarsals (ankle bones-7), Metatarsals (5) and Phalanges (digits-14).
- Pectoral girdles (2x2=4): Clavicle (2) and scapula (2).
- Pelvic girdles (2): 2 coxal bones
Joints
Fibrous (immovable) Joints
E.g. sutures between skull bones
Cartilaginous Joints
(Slightly movable joints)
E.g. Joints between the adjacent vertebrae
Synovial (movable) Joints
They have a fluid filled synovial cavity between articulating surfaces of 2 bones.
Example Of Different Joints
- Ball and Socket Joints: Joints at shoulders and hip.
- Hinge Joints: Knee and wrist joints.
- Pivot Joint: Neck to head joint.
- Gliding Joint: Tarsal to ankle, carpal to wrist, sternum to clavicle etc.
- Saddle Joint: Joints between carpal and metacarpal of thumb.
Disorders Of Skeleton And Muscular System
- Myasthenia Gravis: Auto immune disorder. It affects neuromuscular junction leading to fatigue, weakening and paralysis of skeletal muscles.
- Tetany: Rapid muscle spasm due to low Ca2+ in body fluid.
- Muscular Dystrophy: Progressive degeneration of skeletal muscles. Mostly due to genetic disorder.
- Arthritis: Inflammation of joints.
- Osteoporosis: Age-related disorder characterized by decreased bone mass and increased chances of fractures. Decreased level of estrogen is a common cause.
- Gout: Inflammation of joints due to accumulation of uric acid crystals.
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Chapterwise Notes Class 11 Biology
- The Living World
- Biological Classification
- Plant Kingdom
- Animal Kingdom
- Morphology Of Flowering Plants
- Anatomy Of Flowering Plants
- Structural Organisation In Animals
- Cell-the Unit Of Life
- Biomolecules
- Cell Cycle And Cell Division
- Photosynthesis In Higher Plants
- Respiration In Plants
- Plant-growth And Development
- Breathing And Exchange Of Gases
- Body Fluids And Circulation
- Excretory Products And Their Elimination
- Locomotion And Movement
- Neural Control And Coordination
- Chemical Coordination And Integration
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