Tissues are groups of cells that are similar in structure and function.* Epithelium * Muscle Coverings Movement Linings of surfaces* Connective * Nervous Support Control Bone, ligaments, fat Brain, nerves, spinal cord
Connective TissueIt is a basic type of tissue, ofmesodermal origin,Which provides structuraland metabolic support fortissues and organs.
GENERAL CHARACTERISTICS1- are formed of widely separated, few cellswith abundant extracellular matrix.2- Originate from mesenchyme ( anembryonic tissue ) which develops mainlyfrom mesoderm.3- most C.T. are vascular.
Loose connective tissue• Contains abundant ground substance and tissue fluid, nearly all type of C.T. cells and less amounts of fibers.• Located in subcutaneous tissue, lamina propria of gastrointestinal & respiratory tracts, around blood vessels & organs and under serous membranes.• In inflammatory condition it swells because of increased extra-cellular fluid (Edema).
Collagen synthesis•• polyribosomes polyribosomes polypeptide chain polypeptide chain•• rER & GA modified rER & GA modified procollagen Vit C procollagen•• Exocytosis Exocytosis•• Converted by enzyme Converted by enzyme•• Tropocollagen or Tropocollagen or collagen molecule collagen molecule•• Align to form the final Align to form the final collagen fibrils collagen fibrils
Type of collagen fibers On the basis of the combination of α chains they contain.Type I* :- loose connective tissue , dermis tendon , fibrocartilage & boneType II* :- cartilage & nucleus pulposusType III* :- slender fiber form network, reticular fiberType IV :- basement membraneType V & X :- perilacunar of cartilage
Reticular Fibers•Thin collagen fibers arranged inframework instead of bundles.•Synthesized by the fibroblasts.•They form the reticular network ofsome organs such as lymph nodesand bone marrow.•They present also in basementmembrane.
Elastic fibers (yellow fiber)•Slender, long and branching fibers in looseconnective tissue, but coarse bundles inelastic ligaments.•Formed by the fibroblasts and smoothmuscle cells.•Composed of protein elsatin and can bestretched to one and half times its originallength.•It is present in large arteries, larynx andtrachea, ligamentum flavum and frameworkof the spleen.
Macrophage• They may be fixed or transient.• They are active phagocytes removing cell debris and protecting the body against foreign invaders.• They are derived from monocytes (transient) or from UDMC (histiocytes).• Highly motile, irregular in shape with pseudopodia.• Have dark nucleus and basophilic cytoplasm containing numerous lysosomes, vacuoles and residual bodies.
Plasma cell• basophilic cytoplasm• eccentric nucleus• nucleus clockface or cartwheel• produces globulin antibody 11/20/12 Assist. Prof. Kesorn Sripaoraya 40
Plasma cell• They are derived from B-lymphocytes.• Large ovoid cells with eccentrically placed nucleus.• Its cytoplasm is intensely basophilic (RER).• Its nucleus has the characteristic “clock- face” or “radial spoke” appearance.• They present in areas of chronic inflammation and foreign bodies, where they manufacture and secrete antibodies.
Fat / Adipose Cell in adipocytes.• Loose C.T. very rich• Two types of adipose C.T.• Unilocular (white fat) C.T.: its fat cells are of unilocular type, present in subcutaneous tissue, around organs and blood vessels.• Multilocular (brown fat) C.T., present in infants and hibernating animals, cells are rich in mitochondria, supply heat.
Fat / Adipose Cell Brown adipose tissueWhite adipose tissue
Dense irregular• Contains abundant amounts of fibers with less cells and ground substances.• Has tightly packed coarse collagen bundles arranged randomly in all directions, with few elastic fibers.• Fibroblasts and other less cells are arranged between the collagen fibers.• They are found in dermis of skin, capsule of organs, sheaths around nerves and dura mater.
Dense irregular11/20/12 Assist. Prof. Kesorn Sripaoraya 49
Dense regular• Contains abundant amounts of fibers with less cells and ground substances.• Has tightly packed coarse collagen bundles arranged in parallel fashion to form cord-like cylinders (tendons & ligaments) or sheets (aponeurosis).• Fibroblasts are arranged between the collagen fibers so they appears elongated with their dash-like elongated nuclei.• It is also called white fibrous C.T.
Cell types Main product or Main function activityFibroblast Production of fibers and Structural ground subst.Plasma cell Production of antibody ImmunologicLymphocyte Production of Immunologic immunocompetent cellEosinophil Phagocytosis of Ag-Ab Immunologic complexMacrophage Phagocytosis of foreign Defense& Neutrophil subst. & bacteriaMast cell & Liberation of histamine DefenseBasophilAdipose Storage of neutral fat, Energy reservior; heat production heat production