Locomotion and movement In Humans

In this power point presentation, we discuss about how movement and locomotion takes place in Humans. We discuss about various types of muscles present in humans, how those muscles contract. Also we discuss about the human skeletal system with all the bones and joints in the human body

1. Locomotion and Movement CLASS- XI Biology Prepared by: Bhavya Vashisht

2. Indroduction Movement is one of the most significant features of living beings. Animals and plant exhibit wide range of movements Amoeba - Streaming of protoplasm - Simplest form Cilia, Flagella, Tentacles - Shown by many organisms Humans- Move limbs, jaws, eyelids, etc. Locomotion : Voluntary movements resulting in change of place or location. Locomotory movements : Walking, running, climbing, flying, Swimming

3. WALKING RUNNING FLYING CLIMBING SWIMMING LOCOMOTORY MOVEMENTS

4. Locomotory structures Paramoecium : Cilia - Help in movement of food through cytopharynx and in locomotion. Hydra: Tentacles - Use its tentacles for capturing prey & also for locomotion. Humans: Limbs - Change in body posture and locomotion. Method of locomotion performed by animals vary with their habitats and demands Locomotion generally for search of food, shelter, mate, breeding grounds, favorable climatic conditions or to escape predators.

5. TYPES OF MOVEMENT Human body cells: 3 main types of movements 1. Amoeboid : * Macrophages, Leucocytes in blood * Effected by pseudopodia formed by streaming of protoplasm. * Cytoskeletal elements like microfilaments 2. Ciliary : * Occurs in most of internal tubular organs that are lined by epithelium. * Coordinated movements of cilia in trachea * Passage of Ova through female reproductive tract 3. Muscular : * Movement of limbs, jaws, tongue etc. * Contractile property of muscles effectively used for movement and locomotion. Requires a perfect coordinated activity of muscular, skeletal and neural systems

6. MUSCLE Specialized tissue of mesodermal origin . Contributes about 40-50% body weight of humans Have special properties like excitability, contractility, extensibility and elasticity Classification based on location : Skeletal Muscles Visceral Muscles Cardiac Muscles Closely associated with skeletal components Located in the inner walls of hollow visceral organs of body: alimentary canal, etc. Located in heart Have striped appearance under microscope Don’t have any striation Assemble in branching pattern to form cardiac muscle Called Striated muscles Called Smooth muscles Striated Called Voluntary muscles Called involuntary muscles Involuntary Involved in locomotory actions & changes of body postures Assist in transportation of food through digestive tract Help in contraction and relaxation of heart

7. Skeletal Muscles Made of a number of muscle bundles or fascicles Help together by common collagenous connective tissue layer called fascia . Muscle bundle contains number of muscle fibres . Muscle fibre is lined by plasma membrane called Sarcolemma enclosing s arcoplasm . Muscle fibre : Syncitium ( Sarcoplasm contain many nuclei) Sarcoplasmic reticulum of muscle fibres stores Calcium ions. Presence of large no. of parallel arranged filaments called myofilaments / myofibrils . Myofibril has alternate dark and light bands on it Detailed study of myofibril showed that striated appearance is due to distribution pattern of Actin and Myosin

8. Cross sectional view of Muscle showing muscle bundles and muscle fibres

9. Anatomy of muscle fibre I- Band/ Isotropic Band : Light band containing Actin A- Band/ Anisotropic band : Dark band containing Myosin Both proteins arranged as rod like structure parallel to each other & also to the longitudinal axis of myofibrils Actin filaments : thinner- Thin filaments Myosin filaments : thicker- Thick filaments In centre of each I- Band = Elastic fibre called Z-Line which bisects it Thin filaments firmly attached to Z-Line In centre of each A- Band = thin fibrous membrane- M-Line Thick filaments firmly attached to M-Line A and I bands arranged alternatively throughout length of myofibril Sarcromere : Portion of myofibril between 2 successive Z lines. Functional unit of contraction Resting stage- Edge of thin filaments on either side of thick filaments partially overlap free ends of thick filaments leaving central part of thick filament non overlapped. This part of thick filament is called H-Zone

10. Structure of Contractile Proteins ACTIN FILAMENT- Actin (thin) filament made of 2 F (filamentous) actins helically wound to each other F Actin : Polymer of monomeric G (Globular) Actin 2 Filaments of another protein: Tropomyosin run close to F- Actin throughout its length. Complex protein: Troponin distributed at regular intervals on tropomyosin Resting state: Subunit of troponin masks active binding site for myosin on Actin filaments

11. Structure of Contractile Proteins MYOSIN FILAMENT (THICK)- Many monomeric called Meromyosins constitutes 1 thick filament Meromyosin : 2 parts: Heavy Meromyosin (HMM)- Globular head & short arm Light Meromyosin (LMM)- Tail HMM component project outwards at regular distance & angle from each other from surface of polyerised myosin filament: Cross Arm Globular head is an active ATPase enzyme & has binding sites for ATP and active sites for Actin .

12. CROSS ARM ACTIN BINDING SITES ATP BINDING SITES

13. Mechanism of muscle contraction Explained by Sliding Filament Theory Contraction of muscles takes place by sliding of thin filaments over thick filaments Initiated by signal sent by CNS via motor neuron . Motor neuron + muscle fibre = Motor Unit Neuromuscular Junction/ Motor-end plate: Junction of motor neuron and Sarcolemma in muscle fibre Neural signal reaching this junction releases neurotransmitter (Acetyl Choline ): generate action potential in Sarcolemma This spreads through muscle fibre and causes release of Ca ++ into sarcoplasm Increase in Ca ++ leads to binding of Calcium with subunit of Troponin on Actin filament . This removes masking of active sites for Myosin

14. Mechanism of muscle contraction Utilising energy from ATP hydrolysis , Myosin head binds to expose active sites on Actin to form Cross Bridge . This pulls attached filaments towards centre of A- Band. Z-line attached to actins pulled inward causing shortening of sarcomere : Contraction During contraction, I- Bands gets reduced whereas A- Band retains the length. Myosin release ADP and P 1 & goes back to its relaxed state . New ATP binds and cross link broken . ATP hydrolysed again by myosin head & cycle of Cross Bridge formation& breaking repeated causing further sliding . Process continues till Ca ++ pumped back to sarcoplamic cisternae resulting in masking of Actin filament . This causes return of Z lines back to original position: relaxation.

15. Mechanism of muscle contraction Reaction time of fibres vary in different muscles. Repeated activation of muscles can lead to accumulation of lactic Acid due to anaerobic breakdown of glycogen in them causing fatigue . Muscle contains red colored oxygen storing pigment : myoglobin . Red Fibres : High myoglobin , gives reddish appearance . Contain plenty of mitochondria which utilises large amount of oxygen stored in them for ATP production . Hence called Aerobic muscles . White fibres : Less myoglobin , gives whitish appearance Less number of mitochondria, amount of sarcoplasmic reticulum is high. Depend on anaerobic process for energy

16. SKELETAL SYSTEM Consists of framework of bones and few cartilages . Significant role in movement shown by the body. Bones and cartilages are specialised connective tissues . Bones made up of very hard matrix due to calcium salts in it Cartilages made up of slightly pliable matrix due to chondroitin salts 206 bones and few cartilages Grouped into 2 divisions: Axial skeleton Appendicular skeleton Axial skeleton comprises 80 bones distributed along main axis of the body Constitutes: Skull, vertebral column, sternum and ribs .

17. SKULL Composed of 2 sets of bones: Cranial & facial Total 22 bones: 8 Cranial & 14 facial Cranial bones from hard protective outer covering: cranium of brain Facial bones makes facial region which form the front part of skull 1 U-shaped bone: Hyoid : Present at base of buccal cavity, also included in skull. Each Middle ear: Ear Ossicles : Malleus , Incus & Stapes Skull region articulates with superior region of vertebral column with help of 2 condyles ( dicondylic skull )

18. There are 22 bones in the skull . Including the bones of the middle ear , the head contains 28 bones . Cranial bones are 8 in number . They are: Occipital bone. Parietal bones (2) Frontal bone Temporal bones (2) Sphenoid bone (sometimes counted as facial) Ethmoid bone (sometimes counted as facial) Middle ear: Ear Ossicles : Malleus , Incus & Stapes (3) CRANIAL &EAR BONES

19. Facial bones are 15 in number. They are: Nasal bones (2) Maxillae (upper jaw) (2) Lacrimal bone (2) Zygomatic bone (cheek bones) (2) Palatine bone (2) Inferior nasal concha  (2) Vomer (1) Hyoid bone (1) Mandible (1) FACIAL BONES

20. Formed of 26 serially arranged vertebrae & is dorsally placed. Extends from base of skull & constitutes the main framework of the trunk . Each vertebrae has central hollow portion : Neural Canal through which spinal cord passes 1 st vertebrae: Atlas- Articulates with occipital condyles Vertrbral column starting from skull differentiated into: * Cervical (7) *Thoracic (12) *Lumbar (5) *Sacral (1 fused) * Coccygeal (1 fused) Vertebral column : *Protects spinal cord *Supports head *Serves as point of attachment for ribs and musculature of the back Vertebral column

21. STERNUM AND RIBS Sternum : Flat bone on ventral midline of thorax Ribs: 12 pairs Each rib is thin flat bone connected dorsally to vertebral column & ventrally to sternum 1 st 7 ribs pairs: True ribs : Attached to thoracic vertebrae dorsally & to sternum ventrally with help of hyaline cartilage 8 th , 9 th & 10 ribs pairs: Vertebrochondral / False ribs : don’t articulate directly with sternum but join 7 th rib with help of hyaline cartilage 11 th and 12 th ribs pair: Floating ribs : Not connected ventrally Thoracic vertebrae+ Ribs+ Sternum= Rib Cage

22. APPENDICULAR SKELETON Includes bones of limbs along with their girdles. Each limb made up of 30 bones Bones of hand (Fore limb) Humerus (1) Radius (1) Ulna (1) Carpals/ Wrist Bones (8) Metacarpals (5) Phalanges/ Digits (14)

23. Bones of Hind Limb (Leg) Each hind limb is made up of : Femur/ Thigh Bone (Longest Bone) Tibia (1) Fibula (1) Tarsal/ Ankle Bone (7) Metatarsal (5) Phalanges (14) Cup shaped bone called Patella cover the knee Ventrally (Knee Cap)

24. GIRDLES Pectoral & Pelvic girdle bones in articulation of upper & lower limbs respectively with axial skeleton. Each girdle is formed of 2 halves Each half of pectoral girdle consists of Clavicle & Scapula . Scapula is large triangular flat bone situated in dorsal part of thorax between 2 nd and 7 th ribs Dorsal, flat, triangular body of Scapula has slightly elevated ridge called Spine which projects as flat, expanded process called Acromion . Clavicle articulates with Acromion . Below Acromion is a depression called Glenoid cavity : articulates with head of Humerus from shoulder point . Each clavicle is a long slender bone with 2 curvatures . The bone is commonly called Collar bone

25. PELVIC GIRDLE Consists of 2 Coxal Bones Coxal Bone: formed by fusion of 3 bones: Ilium, Ischium , Pubis At point of fusion of above bones, a cavity: Acetabulum Thigh bone articulates to Acetabulum 2 parts of pelvic girdle meet ventrally & form Pubic Symphysis containing fibrous cartilage.

26. JOINTS Essential for all types of movements involving the bony parts of the body. They are point of contact between bones or between bones and cartilages Force generated by muscles is used to carry our movement through joints , where joint acts as fulcrum. Movability of joints depends on different factors Types of joint: Fibrous joint Cartilaginous joint Synovial joint

27. FIBROUS JOINTS Don’t allow any movement Shown by flat skull bones which fuse end to end with help of dense fibrous connective tissues in form of sutures to form Cranium.

28. CARTILAGINOUS JOINTS Bones involved joined together with help of cartilages. Joints between adjacent vertebrae in vertebral column is of this pattern. Permits limited movements

29. SYNOVIAL JOINTS Presence of fluid filled synovial cavity between articulated surfaces of 2 bones Allows considerable movement Help in locomotion & many other movements. Examples: Ball and socket joint (between Acetabulum of Hip Bone & Femur) Hinge Joint (knee joint) Pivot joint ( between Atlas & Axis) Gliding joint (between Carpals) Saddle joint ( between Carpal and Metacarpal of thumb)

30. Ball and socket JOINTS

31. hinge JOINTS

32. pivot JOINTS

33. gliding JOINTS

34. Saddle JOINTS

35. Disorders Myasthenia gravis : Auto immune disorder Affect neuromuscular junction | Leads to fatigue, weakness, paralysis of skeletal muscle Muscular Dystrophy : Progressive degeneration of skeletal muscle Genetic disorder Tetany : Rapid spasms in muscle due to low Ca ++ in body fluid Arthritis : Inflammation of joints Osteoporosis : Age related disorder Decrease bone mass Increased chances of fractures Decreased levels of Estrogen is common cause Gout: Inflammation of joints Accumulation of uric acid crystals

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