Skeletal System - Bones Structure and Function PDF

Chapter 7: Skeletal System - Bones Structure and Function Bones and Skeletal Tissues Cartilage: Structure and Types Bones: Structure and Types...

Chapter 7: Skeletal System - Bones Structure and Function Bones and Skeletal Tissues Cartilage: Structure and Types Bones: Structure and Types Cartilage Formation Bone Formation Bone Remodeling Bone Diseases 1 Brief outlines only. For details, please refer to the Lecture Text on Top Hat Bone: Compact Bone (dense or cortical bone) Spongy Bones (cancellous or trabecular bone) Cartilage: Types of Cartilages Ligaments and Tendons 2 Brief outlines only. For details, please refer to the Lecture Text on Top Hat Bones: Functions - support - protection - movement - mineral storage - hemopoiesis 3 Brief outlines only. For details, please refer to the Lecture Text on Top Hat Cartilage - 80% water - compressible - no blood vessels or nerves - covered by perichondrium - chondroblasts and chondrocytes, lacunae - extracellular matrix - glucoseaminoglycans (GAGs) - chondroitin sulfate, hyaluronic acid - collagen and elastin fibers Types of Cartilages Hyaline Cartilage: - most abundant - costal cartilages, laryngeal cartilage, tracheal and bronchial cartilages - nasal cartilages - articular cartilages - slightly flexible - collagen and elastin fibers 4 Brief outlines only. For details, please refer to the Lecture Text on Top Hat  Hyaline Cartilage 5 Brief outlines only. For details, please refer to the Lecture Text on Top Hat Elastic cartilage: - ear pinna and epiglottis, larynx - plenty of elastic fibers made of elastin Fibrocartilage: - found in slightly movable joints - resists high pressures - lot of collagen - intervertebral discs in backbone, pubic symphysis - less abundant chondrocytes 6 Brief outlines only. For details, please refer to the Lecture Text on Top Hat  Elastic Cartilage 7 Brief outlines only. For details, please refer to the Lecture Text on Top Hat Fibrocartilage 8 Brief outlines only. For details, please refer to the Lecture Text on Top Hat Growth of Cartilage ** Appositional growth - chondroblasts located deep to the perichondrium secrete new matrix on the superficial face of the cartilage structure - new cartilage grows from outside → in - new matrix is secreted against the existing cartilage ** Interstitial growth - chondroblasts within cartilage divide and secrete new matrix - cartilage expands from within 9 Brief outlines only. For details, please refer to the Lecture Text on Top Hat BONES Compact or Ivory bone Spongy or cancellated bone Classification of Bones: Shape and Size Small bones Long bones Large bones Flat bones Short bones Irregular bones Wormian bones Sesamoid bones Diploe 10 Brief outlines only. For details, please refer to the Lecture Text on Top Hat  11 Brief outlines only. For details, please refer to the Lecture Text on Top Hat  12 Brief outlines only. For details, please refer to the Lecture Text on Top Hat  13 Brief outlines only. For details, please refer to the Lecture Text on Top Hat Gross Anatomy of a Long Bone Diaphysis: - middle part of long bones - contains medullary cavity filled with yellow bone marrow Epiphysis: - the bone end - compact bone on the outside and spongy bone inside - covered with a layer of hyaline (articular) cartilage Epiphyseal plate: - epiphyseal plate and epiphyseal line - between diaphysis and epiphysis 14 Brief outlines only. For details, please refer to the Lecture Text on Top Hat Bone Coverings Periosteum: - covers outer surface of diaphysis - glistening white and double-layered ** outer fibrous layer: - dense irregular connective tissue - provides insertion points for tendons and ligaments ** inner osteogenic layer: - osteoprogenitor cells - osteoblast: bone forming cells - osteoclast: bone resorbing cells Endosteum: - delicate connective tissue membrane - covers the inner surface of the bone - contains both osteoblasts and osteoclasts 15 Brief outlines only. For details, please refer to the Lecture Text on Top Hat Microscopic Anatomy of Bone Tissue Bone Cells Osteoprogenitor cells - stem cells derived from mesenchyme - differentiate (“committed”) to become bone forming cells Osteoblasts - bone forming cells - secrete bone matrix: osteoid (tensile strength) - secrete bone mineral, hydroxyapatite (hardness) - osteoblasts trapped in matrix become osteocytes - calcification and ossification Osteocytes - cells trapped in bone matrix - lacunae and canaliculi - arranged in concentric rings in compact bone Osteoclasts - large, multinucleate - ruffled border - cause bone resorption - bone remodeling 16 Brief outlines only. For details, please refer to the Lecture Text on Top Hat  17 Brief outlines only. For details, please refer to the Lecture Text on Top Hat Compact Bone - diaphysis of long bones - dense and strong Osteon - Haversian system - central canal in the core of osteon - concentric lamellae - osteocytes - lacunae - canaliculi - Perforating or Volkman's canals - Interstitial and Circumferential lamellae: 18 Brief outlines only. For details, please refer to the Lecture Text on Top Hat  19 Brief outlines only. For details, please refer to the Lecture Text on Top Hat Spongy Bone Structure - trabeculae - few cell in thickness (no osteons) - irregularly arranged lamellae and osteocytes (lacuna & canaliculi) 20 Brief outlines only. For details, please refer to the Lecture Text on Top Hat  21 Brief outlines only. For details, please refer to the Lecture Text on Top Hat Bone Development Osteogenesis or ossification ** Intramembranous Ossification ** Endochondral Ossification Intramembranous ossification: - formation of skull bones begins around 8th week - mesenchymal cells differentiate into osteoblasts - primary ossification centers - osteoblasts secrete bone matrix (osteoid) and mineral - bony plates (diploe) - fontanelles - sutures 22 Brief outlines only. For details, please refer to the Lecture Text on Top Hat Endochondral ossification: - ossification of hyaline cartilage - begins at about 8 weeks - perichondrium becomes vascularized - cartilage replaced by bone - primary ossification center in the diaphysis of cartilage - bone collar, shaft, medullary cavity - secondary ossification center at two ends - epiphysis, epiphyseal plate Role of Epiphysis in Bone Elongation - epiphyseal plate - new cartilage forms first, and is then converted into bone - zone of prol;iferation - zone of hypertrophic cartyilage - zone of calcified cartilage - zone of ossification - epiphyseal line 23 Brief outlines only. For details, please refer to the Lecture Text on Top Hat  24 Brief outlines only. For details, please refer to the Lecture Text on Top Hat  25 Brief outlines only. For details, please refer to the Lecture Text on Top Hat  Bone Growth in Width - Bone resorption on the inside by osteoclasts in endosteum - Bone formation on the outside by osteoblasts in periosteum - Medullary cavity becomes wider 26 Brief outlines only. For details, please refer to the Lecture Text on Top Hat Bones and Hormones - Parathyroid hormone (PTH) - Calcitonin - Growth hormone - Thyroid hormones - Estrogens - Vitamin D3 Bone Diseases Osteoporosis Osteopenia Osteomalacia 27 Brief outlines only. For details, please refer to the Lecture Text on Top Hat  28 Brief outlines only. For details, please refer to the Lecture Text on Top Hat  29 Brief outlines only. For details, please refer to the Lecture Text on Top Hat Bone Fractures - Colle’s fracture - Pott’s fracture - Greenstick fracture - Comminuted fracture - Compression fracture 30 Brief outlines only. For details, please refer to the Lecture Text on Top Hat  Bone markings: Tuberosity - large rounded projection Crest - narrow ridge Trochanter - very large blunt, irregular projection Line - narrow line less prominent than crest Tubercle - small rounded projection Epicondyle - raised area above a condyle Spine - a sharp projection (vertebrae) 31 Brief outlines only. For details, please refer to the Lecture Text on Top Hat Head: femur head Facet: a smooth, flat articular surface Condyle: rounded articular surface/projection Ramus: arm-like bar of bone Meatus: canal-like passage way Sinus: air-filled cavity within a bone, lined with mucous membrane Fossa: shallow, basin-like depression for articulation Groove: furrow Fissure: narrow, slit-like opening Foramen: round or oval opening 32 Brief outlines only. For details, please refer to the Lecture Text on Top Hat  33 Brief outlines only. For details, please refer to the Lecture Text on Top Hat