Summary Histology - Connective Tissue Components & Classification

​CONNECTIVE TISSUE CELLS​
​CONNECTIVE TISSUE COMPONENTS​
​FIBROBLASTS & FIBROCYTES​

​I.​ ​Cells:​ ​-​ T​ ypically have​​large active​
​nuclei​​(arrows)​
​-​ ​Fixed cells/Resident cells:​
​-​ ​Eosinophilic cytoplasm that​
​-​ ​Fibroblast and Fibrocyte​
​tapers off in both directions​
​-​ ​Adipocytes​ ​along the axis of the​
​-​ ​Mast cells​ ​nucleus, often referred to​
​-​ ​Fixed macrophages​ ​as​​“spindle-shaped.​​”​
​-​ ​Transient cells:​
​-​ ​Leukocytes​
​-​ ​Plasma cells​
​-​ ​Wandering macrophages​

​II.​ ​Extracellular matrix:​
​A.​ ​Fibers​
​-​ ​Collagenous fibers (Types I, II, III & IV)​ ​-​ ​ ctive​​fibroblasts have​
A
​-​ ​Elastic fibers​ ​large​​, euchromatic nuclei​
​and basophilic cytoplasm,​
​-​ ​Reticular fibers​
​while;​
​B.​ ​Ground substance​
​-​ ​Inactive​​fibroblasts (or​
​-​ ​Glycosaminoglycans​ ​fibrocytes​​) are​​smaller​​with​
​-​ ​Hyaluronic acid​ ​more heterochromatic​
​-​ ​Sulfated GAGs​ ​nuclei (arrows).​
​-​ ​Proteoglycans​
​-​ ​Multi adhesive glycoproteins​


​CONNECTIVE TISSUE CLASSIFICATION​

​I.​ ​Embryonic connective tissue​
​A.​ ​Mesenchyme​
​B.​ ​Mucous connective tissue​

​II.​ ​Mature connective tissue​
​A.​ ​Loose connective tissue​
​1.​ ​Areolar CT​
​2.​ ​Adipose tissue​
​-​ ​ uclei of fibroblasts are​
N
​3.​ ​Reticular CT​
​elongated and, when​
​B.​ ​Dense connective tissue​ ​inactive, these cells have​
​1.​ ​Dense irregular CT​ ​little cytoplasm.​
​2.​ ​Dense regular CT​
​3.​ ​Elastic CT​
​C.​ ​Cartilage​
​1.​ ​Hyaline cartilage​
​2.​ ​Elastic cartilage​
​3.​ ​Fibrocartilage​
​*Cartilage components:​
​-​ ​Cells: Chondrocytes & Chondroblasts​
​-​ ​Cartilage matrix​
​-​ ​Perichondrium​
​D.​ ​Bone tissue​
​1.​ ​Cells​​:​
​a)​ ​Osteoblasts​
​b)​ ​Osteocytes​
​c)​ ​Osteoclasts​
​2.​ ​Haversian system/Osteon parts:​
​a)​ ​Lamellae​
​b)​ ​Lacunae​
​c)​ ​Canaliculi​
​d)​ ​Central canal/Haversian canal​

, ​MAST CELLS​

​-​ ​ omponents of​​loose​
C
​connective tissues​

​-​ ​ ften located​​near small​
O
​blood vessels (BV)​
​PLASMA CELLS​
​-​ T​ ypically​​oval​​shaped, with​
​-​ ​ haracterized by​
C
​cytoplasm filled with​
​cartwheel (clockface)​
​strongly basophilic granules​
​nuclei​​showing the​
​alternating distribution of​
​the heterochromatin (dark)​
​and the euchromatin​​(light).​

​-​ T​ he pale (unstained) area​
​of cytoplasm in each cell is​
​-​ ​ as a single, oval-shaped​
H
​the location of the Golgi​
​nucleus and granules in its​
​complex, which is also​
​cytoplasm.​
​called the Golgi zone. (GZ,​
​Golgi zone.)​




​ADIPOCYTE​
​-​ L​ arge, ovoid cells, with​
​-​ ​ ach adipocyte contains a​
E
​basophilic cytoplasm.​
​large droplet of lipid,​
​appearing white (clear)​
​-​ ​ lasma is often more​
P
​here because the fat was​
​abundant in infected​
​removed during tissue​
​tissues, as in the inflamed​
​preparation.​
​lamina propria shown here.​

​-​ T​ he nucleus of each cell is​
​-​ ​ large pale Golgi​
A
​pushed against the​
​apparatus (arrows) at a​
​periphery of the cell​
​juxtanuclear site in each​
​cell is actively involved in​
​the terminal glycosylation​
​of the antibodies​
​(glycoproteins).​




​MACROPHAGE​

​-​ ​ lack particles fill the​
B
​cytoplasm of these​​active​
​macrophages​

​-​ T​ he​​nuclei are obscured by​
​the phagocytosed​
​NEUTROPHILS​
​materials.​