Connective tissue Most abundant and widely distributed tissues in the body Binds, support, and strengthen body tissues, protect and insulate internal organ, serve as major transport system, compartmentalizes structures such as skeletal muscles, storage, Immune responses It consists of 2 basic element: extracellular matrix and cells Highly vascular Supplied by nerves Mesenchymal cells give rise to cells of connective tissue
Types of connective tissue cells Fibroblast Adipocytes Mast cells WBC Macrophages Plasma cells
Connective tissue cells 1) Fibroblasts: Large, flat cells with branching processes most numerous. Present in all the general connective tissues Secrete the fibers and certain components of the ground substance of the extracellular matrix. 2) Adipocytes: Store triglycerides (fats). Deep to the skin and around organs such as the heart and kidneys.
Connective tissue cells 3) Plasma cells: Develop from B lymphocyte. Secrete antibodies Found in the gastrointestinal and respiratory tracts, salivary glands, lymph nodes, spleen, and red bone marrow. 4) Mast cells: Abundant alongside the blood vessels that supply connective tissue. Produce histamine, a chemical that dilates small blood vessels as part of the inflammatory response, the body s reaction to injury or infection. Produces heparin
Connective tissue cells 5) White blood cells: 6) Macrophages: Develop from monocytes, a type of white blood cell. Irregular shape with short branching projections Capable of engulfing bacteria and cellular debris Types: 1) Fixed macrophages: reside in a particular tissue; i.e. alveolar macrophages in the lungs or splenic macrophages in the spleen. 2) Wandering macrophages: have the ability to move throughout the tissue and gather at sites of infection or inflammation to carry out phagocytosis.
Extracellular matrix (ECM) Ground substances Fibers May be fluid, semifluid, gelatinous or calcified It supports cells, bind them together, store water, provide medium for exchange, it also play role in how tissue migrate, proliferate and change shape, and in how they carry out their metabolic functions It contains water, and large organic molecules such as polysaccharides and proteins, and adhesion proteins (Hyaluronic acid, Chondroitin sulfate, dermatan sulfate, keratan sulfate and fibronectin) Collagen fibers Elastic fibers Reticular fibers
Collagen fibers Very strong and resist pulling forces (tension Not stiff, which allows tissue flexibility. Vary from tissue to another. Collagen fibers in cartilage are surrounded by more water molecules than those in bone, which gives cartilage a more cushioning effect. Can occur in parallel bundles (dense regular connective tissue). great tensile strength. Consist of the protein collagen, most abundant protein in the body, 25 percent of total.
Elastic fibers Smaller in diameter than collagen fibers branch and join together to form a network within a tissue. Consists of molecules of the protein elastin surrounded by a glycoprotein named fibrillin, which adds strength and stability. Strong but can be stretched up to 150% of their relaxed length without breaking. Have the ability to return to their original shape after being stretched, (elasticity). Found in skin, blood vessel walls, and lung tissue.
Reticular fibers Consist of collagen arranged in fine bundles with a coating of glycoprotein provide support in the walls of blood vessels and form a network around the cells in some tissues, such as areolar connective tissue, adipose tissue, nerve fibers, and smooth muscle tissue. Produced by fibroblasts. Much thinner than collagen fibers and form branching networks to provide support and strength. stroma or supporting framework of many soft organs, such as the spleen and lymph nodes. also help to form the basement membrane.
Classification of connective tissue I. Embryonic connective tissue II. a. Mesenchyme b. Mucous connective tissue Mature connective tissue A. Loose connective tissue 1. Areolar connective tissue 2. Adipose connective tissue 3. Reticular connective tissue B. Dense connective tissue 1. Dense regular connective tissue 2. Dense irregular connective tissue 3. Elastic connective tissue C. Cartilage 1. Hyaline Cartilage 2. Fibrocartilage 3. elastic Cartilage D. Bone E. Liquid connective tissue 1. Blood tissue 2. Lymph tissue
Mesenchyme Description: consists of irregularly shaped cells and delicate reticular fibers in a semifluid ground substance Location: under skin in embryo Function: forms all other types of CT
Mucous connective tissue Description: widely scattered fibroblasts and collagen fibers in jellylike ground substance Location: umbilical cord Function: support
Adipose Tissue Description Closely packed adipocytes Have nucleus pushed to one side by fat droplet. Provides reserve food fuel Insulates against heat loss Supports and protects organs Location Under skin Around kidneys Behind eyeballs, within abdomen and in breasts
Areolar Connective Tissue Description semifluid ground substance with: all three fiber types (collagen, reticular, elastic) for support Ground substance is made up by glycoproteins also made and screted by the fibroblasts. Cells fibroblasts, macrophages, mast cells, white blood cells Function Wraps and cushions organs Holds and conveys tissue fluid Important role in inflammation and infection Found around blood vessels, nerves and organs, lamina propria of mucous membranes, dermis
Reticular Connective Tissue Description network of reticular fibers in loose ground substance Function form a soft, internal skeleton (stroma) supports other cell types Location lymphoid organs Lymph nodes, bone marrow, and spleen reticular lamina of basement membrane
Reticular Connective Tissue
Dense regular connective tissue Description: bundles of collagen with fibroblasts present in rows between bundles Location: tendons, ligaments and aponeuroses Function: strong attachment between structures
Dense irregular connective tissue Description: randomly arranged collagen fibers and few fibroblasts Location: fasciae, deeper region of dermis, periosteum, perichondrium, organ capsules, pericardium Function: strength
Elastic connective tissue Description: Consists predominantly of elastic fibers and fibroblasts Location: lung, wall of elastic arteries, trachea, bronchial tubes, ligaments between vertebrae Function: allows stretching of various organs
cartilage Consists of dense network of collagen fibers and elastic fibers embedded in chondroitin sulfate which is responsible for resiliency (ability to assume its original shape after deformation) Matrix up to 80% water. Cells of mature cartilage is called chondrocytes occur singly or in groups within spaces called lacunae. Surrounded by perichondrium (blood vessels, nerves, and source of new cartilage cells). Cartilage has no blood supply (antiangiogenes factor) and no nerves
Hyaline cartilage Description: chondrocytes and collagen fibers in bluish ground substance (resilient gel) Location: ends of long bones, nose, larynx, trachea, bronchi, embryonic and fetal skeleton Function: smooth surface for movement of joints, flexibility and support
Fibrocartilage Description Matrix similar, but less firm than hyaline cartilage Thick collagen fibers predominate Function Tensile strength and ability to absorb compressive shock Location Intervertebral discs Pubic symphysis Discs of knee joint
Elastic Cartilage Description Similar to hyaline cartilage More elastic fibers in matrix Function Maintains shape of structure Allows great flexibility Location Supports external ear Epiglottis
Covering and Lining Membranes Combine epithelial tissues and connective tissues Cover broad areas within body Consist of epithelial sheet plus underlying connective tissue
Three Types of Membranes Cutaneous membrane skin Mucous membrane Lines hollow organs that open to surface of body An epithelial sheet underlined with layer of lamina propria (areolar connective tissue) Serous membrane slippery membranes Simple squamous epithelium lying on areolar connective tissue Line closed cavities Pleural, peritoneal, and pericardial cavities
Covering and Lining Membranes
Covering and Lining Membranes