Biological Tissue PowerPoint Presentation

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Chapter 2 - Biological Tissue Each type of tissue has a specialized function and a distinctive organization

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Types of Tissue Tissue is classified as one of four types: Epithelial Nervous Muscle Connective (Bone, tendon, ligaments, cartilage)

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Types of Tissue:Epithelial Lining tissue layers of cells subject to wear cells regeneration role in diffusion and and bio-electrical conduction

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Type of Tissue: Nerve Forms the nervous system (brain, spinal cord etc.) Basic Cell Neuron Communication Irritability Conductivity Not load bearing Injured under too much tension or compression

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Type of tissue: Muscle Smooth: involuntary and no striations Skeletal: voluntary and striated conductivity, extensibility, elasticity, contractility Cardiac: involuntary and striated

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Type of Tissue: Connective Fibers (collagenous, reticular and elastic) Cells Other macromolecules

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Types of Tissue: Connective Density & Arrangement Loose (fascia) Dense (tendon, lig etc) Irregular Regular

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Types of Loose Tissue: Fibroeslatic Loose network of fibers Extensible: collagen fibers mesh Elastic fibers

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Type of Loose tissue: Areolar Very abundant Mesh of fibers filled with holes (fluid) Limited strength (weak)

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Type of Loose tissue: Reticular Reticular fibers and cells Near Lymph, bone marrow, liver, & spleen Also found around nerves, muscles and blood vessels

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Type of Loose Tissue: Adipose Any loose CT can accumulate fat Very vascular Heat dissipation Cushion

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Components of Connective Tissue Extracellular matrix Fibers: collagen & elastic glycoproteins fluid

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Types of Tissue: Connective Cells resident: produce and maintain extracellular matrix Fibroblasts: form fibers migratory: reaction to injury (immune response) macrophages mast cells Lymphocytes

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Extracellular matrix: Collagen Collagen: 30% of proteins in human Tissue specific & wide organizational arrangement Produced by many cells Fibroblasts, chondrocytes, osteocytes Fibers: chains of amino acids with peptide links Tropocollagen: microfibrils and fibrils Bundle of fibrils form collagen fibers

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Extracellular matrix: Collagen Cross-linking: stiffness and inextensibility Classification Type I: skin, tendon, ligament etc. Type II: cartilage Type III: loose connective tissue, skin, blood vessels

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Extracellular matrix: Elastic Slender & extensible Capable of stretching over 150% of original length Similar chemical composition collagen

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Complex glycoproteins Proteoglycan Glycosaminoglycans Fill spaces between fibers (ground substance) negative ions hydrophilic Cells-associated glycoprotein: cell adhesion Fibronectin: cell migration Chondronectin Anchorin CII

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Tissue Fluid Filtrate of blood Transport of materials: food, O2, waste removal Blockage in lymphs: edema Gives matrix gel characteristics

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Bone Functions protect storage levers blood production Dynamic: remodels and adapts to mechanical, hormonal and calcium changes Cortical and trabercular types of bone

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Bone Development Intramembranous ossification (fast) Endochondral ossification: (limb & axial bones) cartilage calcification primary & secondary center of ossification Growth plate Zone of ranvier (circumferential growth)

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Bone Development Longitudinal growth chondrocytes activity Three regions growth: active cell division maturation: synthesize & secrete EXM transformation: calcification

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Bone Development Intramembranous & endochondral ossification can occur in the same bone Primary ossification center present at birth Affected by loading and hormones Trauma or fracture can affect bone growth (growth plate closure or deformities)

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Bone components Osteoblast & Osteocytes Bone formation Osteoblast (bony surface) Osteocyte: surrounded by matrix Haversian, Volksman and caniliculi Osteoclasts: bone-reabsorbing cells

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Bone components Extracellular matrix: Organic, inorganic and fluid components Inorganic: Minerals (calcium) 50% volume Organic: Type I collagen & proteoglycans (39% of the volume) Fluid (11%) Mineral = stiffness organic = strength Collagen fibers most abundant in the matrix Marrow (canal system)

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Bone macrostructure Woven Bone disorganized pattern of collagen & osteocytes leading to lower mechanical properties. Deposited in novo for rapid mechanical support (fracture callus) Primary Must replace cartilage or woven bone. Multiple thin layers of matrix and cells, organized. Sparse vascular channels Secondary Deposited during remodeling, replaces primary bone

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Cartilage Three kinds: Hyaline elastic fibrocartilage Lack intrinsic blood vessels, nerves and lymphs Nutrients & waste: Diffusion

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Cartilage Growth Interstitial growth chondrocyte division in young cartilage more flexible Appositional growth new cartilage cells beneath perichondrium

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Hyaline Cartilage Glassy appearance Covers most joints and parts of respiratory system Strength & Stiffness Type II collagen (90%) Proteoglycans (Negative Ions and hydrophilic (draw water in the matrix) tends to swell but resisted by collagen fibrils Age  PG’s which  resilience

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Elastic Cartilage Ear, larynx, epiglottis  elastic fibers  flexibility

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Fibrocartilage Stress points due to friction Strong & flexible (filler material)  collagen fibers Growth like CT Four classes Interarticular (meniscus) Connecting (disks) Stratiform (protection) Circumferential (spacer; glenoid labrum)

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Tendons Dense fibrous CT parallel fibers Major component Type I collagen, few elastic fibers Tendon sheath (pulley) Peritenon Insertion: Sharpey’s fibers (anchoring)

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Tendons Myotendinous Junction Increase surface area reduces stress stronger when loaded in parallel to membrane

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Aponeuroses & Fascia Fibrous ribbon like tendons: Palmar aponeurosis Fascia: all dense fibrous connective tissue that are not tendon, ligaments or aponeurosis Interwoven mesh of fibers: stretching in all directions and some cases planes

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Ligaments Dense connective tissue hold bone to bone, resisting tensile forces geometry of fibers specific to function  % of elastic fibers than in tendon Insertions direct: similar to tendons indirect: collagen fibers blend with periosteum 2/3 of a ligament is water

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Ligaments Sensory receptors: information about movement, position and pain Ruffini Pacinian corpuscles Golgi tendon organ Free nerve endings Joint proprioception? Information about changes in muscle stiffness Yellow ligaments: mostly elastic fibers (vocal cords, ligamentum flava)

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Ligaments and Injury Ankle Sprains & proprioception ACL & gait & proprioception

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Skeletal Muscle Two basic elements: Contractile proteins and connective tissue

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Connective Tissue Functional stiffness Improve transmission of tension reduce wear & tear

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Microstructure Fibers Myofibrils Sarcomere Myofilaments Actin Myosin

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Microstructure Myofilaments Sliding Filament theory

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Fibers Types

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Muscle fibers Series & parallel arrangement Angle of pennation longitudinal or fusiform (parallel) pennate (cross-sectional area)

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Neural Components Motor unit: One motor neuron and all the fibers it controls All-or-none-principle  muscle tension recruitment * frequency of stimulus

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Mechanical Components Muscle length Velocity of contraction Type of action isometric concentric eccentric Passive properties elastic energy stored Muscle stiffness: internal resistance by cross-bridges Tension Length Passive active Total

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Joints Junction between bone-bone, cartilage-bone, teeth-bone

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Classification Synarthrodial Immovable & no joint cavity Amphiarthrodial slightly movable & no joint cavity Diarthrodial (synovial) movable with joint cavity Synovial joints gliding (carpals) hinge (elbow) Pivot (radio-ulnar) Ellipsoid (wrist) Condyloid (metacarparls) Saddle Ball & socket

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Components of Synovial Joints Joint cavity Synovial membrane Bursae Intrinsic & extrinsic ligaments Articular cartilage Fibrocartilage