Locomotor System PDF

Locomotor System – I Skeletal component Lecture 3 Dr Sahar Ijaz Assistant Professor Department of Anatomy and Histology Dr. Sahar Ijaz (ANAT 02101, 2023-2024), 03/10/ 2024 basic stem of ppt courtesy Dr. Hafsa Zaneb 1 Learning Outc...

Locomotor System – I Skeletal component Lecture 3 Dr Sahar Ijaz Assistant Professor Department of Anatomy and Histology Dr. Sahar Ijaz (ANAT 02101, 2023-2024), 03/10/ 2024 basic stem of ppt courtesy Dr. Hafsa Zaneb 1 Learning Outcomes By the end of this lecture, the students will be able to Bones according to topography, ontogeny, ossification, shape & Classify matrix arrangement Describe The organization of a long bone Chemical composition of bone to its biomechanical Relate properties LO-1 LO-2 LO-3 Dr. Sahar Ijaz (ANAT 02101, 2023-2024), 03/10/ 2024 2 basic stem of ppt courtesy Dr. Hafsa Zaneb  LOCOMOTOR SYSTEM Skeleton Muscles Bones Cartilages Ligaments Joints Constitutes the passive part of the Constitutes the active part of the locomotor system locomotor system Functional unit complemented by the nervous, circulatory and endocrine systems Dr. Sahar Ijaz (ANAT 02101, 2023-2024), 03/10/ 2024 3 basic stem of ppt courtesy Dr. Hafsa Zaneb  FUNCTIONS OF BONES 1. Support Example? 2. Protection Example? Determine the shape and 3. Movement Bone as levers. Example? structure of bone 4. Metabolic support Hematopoiesis and mineral reservoir. Which minerals? Dr. Sahar Ijaz (ANAT 02101, 2023-2024), 03/10/ 2024 4 basic stem of ppt courtesy Dr. Hafsa Zaneb  LO-1 LO-2 LO-3 How are bones classified topographically? (1) Cranial Skeleton bones of skull (2) Post Cranial Skeleton (1) Axial - vertebral column, ribs, sternum (2) Appendicular - bones of the limbs Specialized (Visceral) skeleton - bones developed in the substance of viscera / soft tissues Dr. Sahar Ijaz (ANAT 02101, 2023-2024), 03/10/ 2024 5 basic stem of ppt courtesy Dr. Hafsa Zaneb  LO-1 LO-2 LO-3 How are bones classified based on Ontogeny? Somatic Skeleton – formed in the body wall (post cranial skeleton) Visceral Skeleton – derived from pharyngeal arches Dr. Sahar Ijaz (ANAT 02101, 2023-2024), 03/10/ 2024 6 basic stem of ppt courtesy Dr. Hafsa Zaneb  LO-1 LO-2 LO-3 How are bones classified based on Development path/Ossification? – reflect phylogeny! Bones developed through Endochondral Ossification Example: Long bones, vertebrae, pelvic bones etc. Bones developed through Intramembranous Ossification Example: Skull vault, maxilla, mandible, clavicle etc. 03/10/ 2024 Dr. Sahar Ijaz (ANAT 02101, 2023-2024), 7 basic stem of ppt courtesy Dr. Hafsa Zaneb  LO-1 LO-2 LO-3 How are bones classified according to Shape? What causes the bones to be different in shape and appearance? Function – Movement, protection, shock absorbance Genetic determination Static and dynamic influences Muscle or tendon attachment s on bones cause the development of processes, tubercles, crests, spines, roughened surfaces, depressions or notches. Blood vessels, nerves or organs contour the surface of bone (groove) Factors causing variation in the number of bones of skeleton Age  Fusion during growth of skeletal elements Dr. Sahar Ijaz (ANAT 02101, 2023-2024), 03/10/ 2024 8 basic stem of ppt courtesy Dr. Hafsa Zaneb  LO-1 LO-2 LO-3 How are bones classified according to Shape? LONG BONES Characterised by a shaft or body (diaphysis), a proximal and distal end (epiphysis) and a growth plate (metaphysis). Typically found in appendicular skeleton Act as levers Develope from 3 ossification centers. Dr. Sahar Ijaz (ANAT 02101, 2023-2024), 03/10/ 2024 9 basic stem of ppt courtesy Dr. Hafsa Zaneb  LO-1 LO-2 LO-3 How are bones classified according to Shape? FLAT BONES Core of spongy bone (diploe) sandwiched between two layers of compact bone e.g. scapula, skull bones SHORT BONES Cylindrical, cuboid, or spheroid Core of spongy bone covered with compact bone e.g. carpals, tarsals, SESAMOID BONES vertebrae (Irregular bones) Develop in the muscles / tendons Core of spongy bone covered with compact bone e.g. patella Dr. Sahar Ijaz (ANAT 02101, 2023-2024), 03/10/ 2024 10 basic stem of ppt courtesy Dr. Hafsa Zaneb  LO-1 LO-2 LO-3 Specialized Bones Pneumatic bones – air-filled bones Mammals: Confined to the skull e.g. paranasal sinuses Paranasal Sinuses: Nasal mucosa invades skull bones and replaces diploe (spongy bone between the outer and inner layers of compact bones) Postnatal remodeling gives characteristic shape to face Birds: Extensive system of air-filled cavities in postcranial skeleton in communication with the respiratory organs. Dr. Sahar Ijaz (ANAT 02101, 2023-2024), 03/10/ 2024 11 basic stem of ppt courtesy Dr. Hafsa Zaneb  LO-1 LO-2 LO-3 How are bones classified according to Matrix Arrangement? LAMELLAR BONE – mature bone Spongy bone - Collagen lamellae arranged parallel to each other Compact bone - Lamellae are organized concentrically around Haversian canal WOVEN BONE – immature bone In both Spongy and compact Collagen fibers are arranged in irregular arrays Smaller amounts of mineral substance Higher proportion of osteocytes to lamellar component Woven bone is eventually converted to lamellar bone Dr. Sahar Ijaz (ANAT 02101, 2023-2024), 03/10/ 2024 12 basic stem of ppt courtesy Dr. Hafsa Zaneb  LO-1 LO-2 LO-3 LEARNING OUTCOMES By the end of this lecture, the students will be able to  1. Classify bones according to topography, ontogeny, development, shape and matrix arrangement 2. Describe the organization of a long bone 3. Relate chemical composition of bone to its biomechanical properties Dr. Sahar Ijaz (ANAT 02101, 2023-2024), 03/10/ 2024 13 basic stem of ppt courtesy Dr. Hafsa Zaneb  LO-1 LO-2 LO-3 ORGANIZATION OF A LONG BONE Schematic longitudinal section of long bone (bovine Humerus) 1, Articular cartilage 2, spongy bone 2′ epiphysial cartilage 3, compact bone 4, periosteum, partly reflected 5, nutrient foramen 6, medullary cavity 7, roughened area for attachment of muscle or ligament 8, distal extent of medial epicondyle 9, tendons of origin of carpal and digital flexors Dr. Sahar Ijaz (ANAT 02101, 2023-2024), 03/10/ 2024 14 basic stem of ppt courtesy Dr. Hafsa Zaneb  LO-1 LO-2 LO-3 Form of the bone is determined by a Cortex of compact (3) bone composed of thin lamellae arranged mainly in series of concentric tubes around small central canals (Osteone – more in Histology) Shaft / Diaphysis Cortex is thick toward the middle of the shaft (3) Smooth external surface except at site for muscles or ligaments attachment (7) (e.g.?) Inner surface is rough and bounds a central medullary cavity Dr. Sahar Ijaz (ANAT 02101, 2023-2024), 03/10/ 2024 15 basic stem of ppt courtesy Dr. Hafsa Zaneb  LO-1 LO-2 LO-3 Extremities / Epiphysis Occupied by cancellous or spongy bone (2), which forms a three-dimensional lattice of interlacing spicules, plates, and tubes of varying density. Medullary cavity / Interstitial spaces of the spongy bone are occupied by bone marrow (Types of marrow? Their function? Sequence of disappearance of active marrow?) Growth Plate / Metaphysis (2’) Plates of hyaline cartilage placed between diaphysis and the two Epiphysis Dr. Sahar Ijaz (ANAT 02101, 2023-2024), 03/10/ 2024 16 basic stem of ppt courtesy Dr. Hafsa Zaneb  LO-1 LO-2 LO-3 Articular Surface (1) Smooth and covered in articular cartilage (Hyaline) Cartilage variable thickness calcified in its deepest layer blends with periosteum and joint capsule towards the periphery Periosteum (4) Covers the external surface of bone except at articular surface Tough double-layered structure Outer fibrous and deeper cellular (osteogenic) layer Endosteum Thin CT lining of the marrow cavity (diaphysis) and marrow spaces (spongy bone) Dr. Sahar Ijaz (ANAT 02101, 2023-2024), 03/10/ 2024 17 basic stem of ppt courtesy Dr. Hafsa Zaneb  LO-1 LO-2 LO-3 QUESTIONS? Dr. Sahar Ijaz (ANAT 02101, 2023-2024), 03/10/ 2024 18 basic stem of ppt courtesy Dr. Hafsa Zaneb  LO-1 LO-2 LO-3 Blood supply of a long bone 1 - Epiphysial arteries 2 - Metaphysial arteries 3 - Nutrient artery 4 - Artery of bone marrow 4′ - Vein of bone marrow 5 - Periosteal arteries 5′ - Periosteal vein 6 - Anastomosis between periosteal & marrow aa 7 - Capillaries of the cortex 8 - Sinusoids in the bone marrow 9 - Growth cartilage 10 - Cortex Dr. Sahar Ijaz (ANAT 02101, 2023-2024), 03/10/ 2024 19 basic stem of ppt courtesy Dr. Hafsa Zaneb  LO-1 LO-2 LO-3 Please read and discuss with peers Summary Blood Supply: Nutrient artery passes through nutrient foramen which simulates an oblique fracture in radiographs Bifurcates and re-branches Supplies sinusoids of the marrow tissue, osteons (compact bone) Establishes collateral circulation through anastomoses with branches of Metaphyseal and epiphyseal vessels (Intramedullary pinning??) Summary Venous Drainage: Large, thin-walled veins that accompany the major arteries Emerge through the nutrient, epiphyseal, and metaphyseal foramina Capillaries within cortical tissue drain into venules within the periosteum – Centrifugal circulation Dr. Sahar Ijaz (ANAT 02101, 2023-2024), 03/10/ 2024 20 basic stem of ppt courtesy Dr. Hafsa Zaneb  LO-1 LO-2 LO-3 Nerve Supply Lymphatic Drainage Nerve supply Nerves accompany the blood vessels Sensory Periosteal innervation Vasomotor supply for blood vessels No Lymphatics Dr. Sahar Ijaz (ANAT 02101, 2023-2024), 03/10/ 2024 21 basic stem of ppt courtesy Dr. Hafsa Zaneb  LO-1 LO-2 LO-3 PHYSICAL PROPERTIES OF BONE Fresh dead bone - Yellowish-white Macerated or boiled and bleached - White Specific gravity of fresh compact bone - 1.93 Tensile strength - Nearly twice that of oak Dr. Sahar Ijaz (ANAT 02101, 2023-2024), 03/10/ 2024 22 basic stem of ppt courtesy Dr. Hafsa Zaneb  LO-1 LO-2 LO-3 LEARNING OUTCOMES By the end of this lecture, the students will be able to 1. Classify bones according to topography, ontogeny, development, shape and matrix arrangement  2. Describe the organization of a long bone 3. Relate chemical composition of bone to its biomechanical properties Dr. Sahar Ijaz (ANAT 02101, 2023-2024), 03/10/ 2024 23 basic stem of ppt courtesy Dr. Hafsa Zaneb  LO-1 LO-2 LO-3 What determines the biochemical properties of bone tissue? Stiffness, Compressive strength, Flexibility, Tensile strength Bone mineral – 65% What contributes to the stiffness Calcium phosphate (85-90%) and compressive strength in bone? Calcium carbonate (8-10%) Magnesium phosphate (1.5 %) Calcium fluoride (0.3 %) Organic Ground Substance – 35% What contributes to the flexibility Type I collagen fibres (90 %) and tensile strength in bone? Glycosaminoglycans Proteoglycans Chondroitin-4-sulphate Chondroitin-6- sulphate and Keratin sulphate Dr. Sahar Ijaz (ANAT 02101, 2023-2024), 03/10/ 2024 24 basic stem of ppt courtesy Dr. Hafsa Zaneb  Shear: parallel to T/S DOI: 10.5772/intechopen.112777 Dr. Sahar Ijaz (ANAT 02101, 2023-2024), 03/10/ 2024 25 basic stem of ppt courtesy Dr. Hafsa Zaneb  LO-1 LO-2 LO-3 Dr. Sahar Ijaz (ANAT 02101, 2023-2024), 03/10/ 2024 26 basic stem of ppt courtesy Dr. Hafsa Zaneb  LO-1 LO-2 LO-3 Stress: pressure What else determines the strength of a bone? applied on per unit area Water content – 25% of wt Strain: change/deformation Bone porosity (amount of bone volume filled with pores) resulted or Effect of porosity on strength? Change in length per original length Low porosity bone (Cortical bone) High porosity bone (Trabecular bone) Compact mineralized Less compact Forms the shaft of long bone & Forms extremities of long bone & Outer layer of all bones Core of all other bones Withstands greater stress but less Withstands greater strain before strain (more stiff) fracturing Dr. Sahar Ijaz (ANAT 02101, 2023-2024), 03/10/ 2024 27 basic stem of ppt courtesy Dr. Hafsa Zaneb  LO-1 LO-2 LO-3 LEARNING OUTCOMES By the end of this lecture, the students will be able to 1. Classify bones according to topography, ontogeny, development, shape and matrix arrangement 2. Describe the organization of a long bone  3. Relate chemical composition of bone to its biomechanical properties Dr. Sahar Ijaz (ANAT 02101, 2023-2024), 03/10/ 2024 28 basic stem of ppt courtesy Dr. Hafsa Zaneb Sample Questions 1. How will decrease in collagen component of bone affect its tensile strength? 2. The most abundant mineral component in bone tissue is __________ 3. ___________ is the most abundant organic component of bone 4. Where is the spongy bone distributed in the body, and what roles are associated with it? 5. Classify bones according to shape 6. Define Epiphysis, Metaphysis, Diaphysis, Periosteum, Endosteum etc. For this lecture: 1- this presentation 2- the topic of “Bones” - page 12 to 16 in the Text book of Veterinary Anatomy by Dyce – 4th edition. Dr. Sahar Ijaz (ANAT 02101, 2023-2024), 03/10/ 2024 29 basic stem of ppt courtesy Dr. Hafsa Zaneb The next class Osteology 2 Make sure that you Are done with your assignments or recommended reading Have gone through the previous lecture Have gone through the outline of the topic for that day’s lecture. Dr. Sahar Ijaz (ANAT 02101, 2023-2024), 03/10/ 2024 30 basic stem of ppt courtesy Dr. Hafsa Zaneb