University:
Stanford University
Course:
MED 304A | Cardiovascular Medicine
Academic year:

2023
Views:

169

Pages:

2
Author:

Alex P

CONNECTIVE TISSUES‬ ‭I)‬ ‭Introduction‬ ‭1)‬‭Definition‬ ‭Connective tissues are common or specialized supporting tissues comprising:‬ ‭-‬ C ‭ ells‬‭:‬ ‭-‬ ‭Non-cohesive or joined‬‭(except a few cells like fibroblasts which‬ ‭have gap junctions)‬ ‭-‬ ‭Not necessarily polarized‬‭(they can therefore be polarized)‬ ‭-‬ A ‭ n extracellular matrix (ECM)‬‭:‬ ‭-‬ ‭Fibers‬ ‭-‬ ‭Fundamental substance‬ ‭-‬ ‭Water‬ ‭Note: it is not possible to find epithelial cells in the connective tissue, but in the‬ ‭thickness of the dermis in the physical sense of the term there are vessels or sweat‬ ‭glands with epithelial cells which, however, remain separated from the connective‬ ‭tissue by a basal lamina.‬ ‭2)‬ ‭Nomenclature and types‬ ‭Connective tissues are classified into 2 main categories:‬ -‭ ‬ C ‭ ommon (non-specialized) connective tissues‬ ‭-‬ ‭Specialized connective tissues‬ ‭There are 4 main types of common and specialized connective tissue cells that‬ ‭define the tissue:‬ ‭ ell‬ C ‭Fibroblast‬ ‭Adipocyte‬ ‭Chondrocyte‬ ‭Osteocyte‬ ‭ abric‬ F ‭Common connective tissues‬ ‭Fat tissue‬ ‭Cartilage‬ ‭Bone‬ ‭Presence of fibroblasts and adipocytes almost everywhere in connective tissues.‬ ‭3)‬‭General‬ ‭Connective tissues:‬ ‭-‬ A ‭ re vascularized and innervated‬‭(‬‭except the cartilage and stroma of the‬ ‭cornea‬‭): they contain blood vessels, lymphatics and nerves‬ ‭-‬ ‭Constitute a more or less rigid framework of‬‭:‬ ‭-‬ ‭Organs‬ ‭-‬ ‭Fabrics‬ ‭-‬ ‭Systems communication pathways (vessels, nerves)‬ ‭-‬ ‭Connect the tissues together‬‭(like blood which is a specialized connective tissue liquid)‬ ‭-‬ ‭Are the main site of inflammation phenomena‬ ‭4)‬‭Embryological origins‬ ‭Connective tissues come from:‬ -‭‬ F ‭ rom the mesoblast‬‭(= mesenchyme)basically‬ ‭-‬ ‭From the ectoblast‬‭and in particular the neural crests which provide the connective tissue of‬ ‭the face‬ ‭ he tissues and cells are often of mesenchymal origin, there are phenomena of‬ T ‭epithelial-‬‭mesenchymal transition‬‭, i.e. cells of an epithelium can give rise to the‬ ‭underlying connective tissue (plasticity phenomenon).‬ ‭Please note: the concept of mesenchyme or stroma in adults is different from‬ ‭embryonic mesenchyme.