Question

Explain about all the fibers and cells present in connective tissues in detail.

Answer 1

The common cell types in connective tissue include: fibroblasts, mast cells, plasma cells, macrophages, adipocytes, and leukocytes.



#Fibroblasts are the most common cell type of connective tissue. They produce both fibers and amorphous ground substance. Typically only the oval nuclei are visible. These cells are found associated with the fibers listed above. In the tendon, fibroblasts are seen as elongate nuclei found sandwiched between collagen fibers .

#Mast Cells are round/oval cells that contain granulesthat are metachromatic because of their glycosaminoglycan content; these cells are easily seen in the connective tissue spread.

#plasma cells . The cells are ovoid with basophilic cytoplasm, due to rER. The diagnostic feature of plasma cells is their eccentric round nuclei commonly described as "clock face" nuclei . This appearance is due to heterochromatin clumps.

#Adipocytes , fat cells are large cells specialized in storage of neutral fats. Lipid is removed in routine tissue preparation. Consequently the cell appears as a thin rim of cytoplasm surrounding the vacuole of dissolved lipid. The nucleus is eccentric and flattened. Adipose tissue is a connective tissue with a predominance of adipocytes.

#macrophages (dust cells) are found easily in the air spaces where these cells have either ingested carbon particles or erythrocytes. Some may appear as vacuolated cells. One can infer the identity of a macrophage by its indented nucleus .

#Leukocytes are white blood cells that are readily found in connective tissue. Lymphocytes (similar in size to red blood cells) are the most common connective tissue leukocyte. Aggregates of lymphocytes are often found associated with the mucosal epithelium of the GI tract, such as this slide of the esophagus. They have a small amount of slightly basophilic cytoplasm and alarge, darkly stained nucleus because of condensed chromatin



>Fibres in connective tissue can be divided into three types: collagen fibres, reticular fibres and elastic fibres.


Extracellular Substance

#Collagen fibres

Collagen fibres are the dominant fibre type in most connective tissues. The primary function of collagen fibres is to add strength to the connective tissue.

Each of these fibrils is composed of microfibrils


Microfibrils are assemblies of tropocollagen, which, in turn, is an spiral-like assembly of three collagen molecules (triple helix). The organisation of the tropocollagen within the microfibrils is highly regular.


#Reticular fibres


Reticular fibres are very delicate and form fine networks instead of thick bundles.
Reticular fibres give support to individual cells, for example, in muscle and adipose tissue.

#Elastic fibres

Elastic fibres are coloured in fresh tissues - they are light yellow - but this colouration is only visible if large amounts of elastic fibres are present in the tissue, for example, in the elastic ligaments of the vertebral column.