Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Connective Tissue Characteristics  Characteristics:  Most widely distributed tissues  Most abundant tissue in weight  Resident Cells are present in stable numbers  Wandering Cells appear temporarily in response to injury or infection  Extracellular matrix  Non-living material that surrounds living cells  Tensile Strength – ability to stretch & recoil

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Connective Tissue Functions  Functions:  Binds body tissues together  Supports the body  Provides protection

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Connective Tissue Cells  Cell Types:  Fibroblast “Fiber Builder”  Most common resident cell  Large, star-shaped  Secretes proteins into matrix to make fibers  Macrophage – “Big Eater”  Wandering White Blood Cells  Clear away debris by phagocytosis  Mast Cells  Release heparin to prevent blood clotting  Release histamine in response to allergins

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Extracellular Matrix  Two main elements  Ground substance –  Mostly water ( water reservoir)  Hyaluronic Acid  Fibers  Collagen fibers  Elastic fibers  Reticular fibers  Matrix varies from fluid (blood) to solid (bone)

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Connective Tissue Types  Bone (osseous tissue)  Structure  Rigid Matrix of calcium salts and collagen fibers  Osteocytes (bone cells) in lacunae (cavities) with cytoplasmic processes in canaliculi (tunnels)  Arranged in thin, concentric layers called lamellae  Osteonic Canal (Haversian)- longitudinal tubes containing blood vessel  Osteon (Haversian System) – cylinder- shaped unit of osteocytes & lamellae around osteonic canal. Many of these osteons cemented together make up bone. Figure 3.19a

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Connective Tissue Types  Bone (osseous tissue)  Function  Framework /Support  Protection  Stores Salts  Forms blood cells  Location  Skeletal System Figure 3.19a

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Connective Tissue  Cartilage  Structure  Chondrocytes – cartilage cells  Chondrocytes located in lacunae  Enclosed in perichondrium  Lacks direct blood supply; diffusion from perichondrium  3 Types:  Hyaline; Elastic; Fibrocartilage

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Connective Tissue Types  Hyaline cartilage (Most common cartilage) “milk glass”  Structure  Fine collagen fibers  Rubbery matrix  Function  Bone Development Figure 3.19b

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Connective Tissue Types  Hyaline cartilage Location  ‘Rings’ in respiratory walls  Ends of bones  Nose  Entire fetal skeleton  Attaches ribs to breastbone  Forms supporting structure of larynx/voicebox Figure 3.19b

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Connective Tissue Types  Elastic cartilage  Structure  Elastic fibers  Function  Provides elasticity  Flexible framework  Location  Vocal cords (larynx)  External ear

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Connective Tissue Types  Fibrocartilage  Structure  Large collagen fibers  Highly compressible (tough)  Function  Shock absorber  Location  Intervertebral disks  Cushions in knees Figure 3.19c

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Connective Tissue Types  Dense Connective Tissue  Structure  Closely-packed collagen fibers  Few Fibroblasts  Function and Location  Tendon – attach muscle to bone  Ligaments – attach bone to bone Figure 3.19d

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Connective Tissue Types  Areolar (Loose) C. T.  Structure  ‘Areolar’ – small open spaces  Fibroblasts between elastin & collagen  Soft, pliable tissue  Function  Holds organs in place  Tissue fluid provides water & salts  Can soak up excess fluid  Edema- swelling from excess fluid  Location  Around organs  Beneath skin  Between muscles Figure 3.19e

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 3.19f Connective Tissue Types  Adipose tissue  Structure  Form of Loose C.T.  Fat-filled vacuole occupies cell  Nucleus pushed to membrane  Functions  InsulationFuel storage  Protective cushion  Location  Beneath skinAround kidneys  Between musclesAround heart  Behind eyeballsAround joints  Abdominal membranes

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Connective Tissue Types  Blood  Structure  RBC Platelets  WBC Plasma- Fluid matrix  Function  Transports materials  Maintains homeostasis  Location  Cardiovascular System Figure 3.19h

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Muscle Tissue  Function is to produce movement  Three types  Skeletal muscle  Cardiac muscle  Smooth muscle

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Muscle Tissue Types  Skeletal muscle  Can be controlled voluntarily  Cells attach to connective tissue  Cells are striated  Cells have more than one nucleus Figure 3.20a

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Muscle Tissue Types  Cardiac muscle  Found only in the heart  Function is to pump blood (involuntary)  Cells attached to other cardiac muscle cells at intercalated disks  Cells are striated  One nucleus per cell Figure 3.20b

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Muscle Tissue Types  Smooth muscle  Involuntary muscle  Surrounds hollow organs  Attached to other smooth muscle cells  No visible striations  One nucleus per cell Figure 3.20c

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue  Neurons and nerve support cells  Function is to send impulses to other areas of the body  Irritability  Conductivity Figure 3.21

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Tissue Repair  Regeneration  Replacement of destroyed tissue by the same kind of cells  Fibrosis  Repair by dense fibrous connective tissue (scar tissue)  Determination of method  Type of tissue damaged  Severity of the injury

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Events in Tissue Repair  Capillaries become very permeable  Introduce clotting proteins  Wall off injured area  Formation of granulation tissue  Regeneration of surface epithelium

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Regeneration of Tissues  Tissues that regenerate easily  Epithelial tissue  Fibrous connective tissue and bone  Tissues that regenerate poorly  Skeletal muscle  Tissues that are replaced largely with scar tissue  Cardiac muscle  Nervous tissue within the brain and spinal cord

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Developmental Aspects of Tissue  Epithelial tissue arises from all three primary germ layers  Muscle and connective tissue arise from the mesoderm  Nervous tissue arises from the ectoderm  With old age there is a decrease in mass and viabililty in most tissues