BONE & CARTILAGE

• Cartilage & Bone are special types of dense connective tissue
• 3 Types of Cartilage: Hyaline, Elastic & Fibrous Cartilage
• HYALINE CARTILAGE - most abundnt type of cartilage in the body
• WAter accounts for 70% - 80% of the wet weight of the tissue
• Hyaline cartilage is mostly made up of proteoglycans
• BASAL LAMINA - protects the chondorcytes against mechanicl stress
• INTERTERRITORIAL MATRIX - area in between territorial matrices
• CHONDRONECTIN - fibronectin - like substance that promotes the adherence of collagen fibers
• MATRIX of HYALINE CARTILAGE: Homogenous, Basophilic & Collagen Type II
• LOCATIONS of Hyaline Cartilage: Upper Respiratory Tract & Articular Enf, Epiphyseal of long bones & Fetal Skeleton
• FUNCTION of Hyaline Cartilage: Provides smooth, low friction surfaces in joints, Structural suppor for respiratory tract
• ELASTIC CARTILAGE is present in: Epiglottis, Auditory Tube, External Acoustic Meastus, External Ear, Larynx
• MATRIX OF ELASTIC CARTILAGE: Elastic Fibers & Collagen Type II
• FUNCTION OF ELASTIC CARTILAGE: Provides flexible shape & support of soft tissues & flexibility
• PERICHONDRIUM - supplies cartilage with Oxygen & nutrients
• MATRIX OF FIBROUS CARTILAGE: Collagen Type I
• LOCATIONS OF FIBROUS CARTILAGE: Intervertebral Discs, Pubic Symphysis, Meniscus & Tendons & Ligaments
• FUNCTION OF FIBROUS CARTILAGE: Cushioning, Tensile Strenght, Resistance to tearing & compression
• Type of cartilage that has NO perichondrium - Fibrous Cartilage
• Bones serves as a storehouse for: Calcium &PHosporus
• SHORT BONES - are cuboidal & are confined to the wrist & ankle
• FLAT BONES - typified by the sternum, scapulae & many bones of the skull
• IRREGULAR BONES - include vertebrae, hip bones, & the bones of the skull that are not flat
• SESAMOID BONES - those that develop in tendons that rub bony surfaces
• 2 formsn of bone: Compact & Spongy
• In terms of mass, Spongy Bone accounts for 20% - 25% of the body's total skeletal mass
• Compact Bone accounts for 75% - 80%
• OSTEOGENIC POTENCY - the ability to form bone
• PERIOSTEUM - covers the external surface of the bone
• ENDOSTEUM - covers the internal surface in bone
• LAMELLAE - thin layers
• Size of lamellae - 3 - 7 micrometer
• LACUNAE - cavities
• CANALICULI - numerous small canals
• All forms of cartilage form from - embryonic mesenchyme
• APPOSITIONAL CARTILAGE GROWTH - occurs when cartilage cells grow from the perichondrium by addition of new cells to the surface of the tissue
• INTERSTITIAL GROWTH - Cartilage cells grow from the chondrocytes within the cartilage, by the addition of new cells within the existing tissue
• FUNCTIONS OF BONE: Body Support, Organ Protection, Storage of fats & Minerals, Body Movement, Blood Cell Formation
• 4 Types of Bone Cells: Osteogenic Cells, Osteoblasts, Osteocytes & OSteoclasts
• OSTEOGENIC CELLS - they are stem cells that have limited potential