animal science general biology
lab . no. 3
connective tissue
connective tissue consist of three basic component :
1- specialized cell .
2- extra cell protein fibers
3-extra cellular material known as the ground substance also called matrix .
the fibers and ground substance constitute the matrix that surrounds the cells, where as cell make up the bulk of epithelial tissue .
connective tissue are found through of the body but are never exposed to the outside environment the function of connective tissue in :
1. support and establishing a structure for the body .
2. as medium for exchange between the blood and tissue .
3. for storage especially in the form of lipids .
4. for the protection from invading microorganism .
5. transporting fluid & dissolved materials from one region of the body to another .
6. repair .
connective tissue cells
they usually divided into tow groups based on their ability to move within the connective tissue :
? fixed cells include fibrocytes , adipocytes( fat cell ) ,reticular cell , and mesenchymal cells .
? wandering cells include macrophage , monocyte , lymphocyte , plasma cell , eosinophils , and mast cell .
? fibrocystes or fibroblast
are the most common cell type in connective tissue their nucleus is oval sometime flattened and their cytoplasm have processes as star . fibrocyte dose not contain many organelles but if fibrocytes are stimulated for example by damage to the surrounding tissue , in the case the fibrocyte is
transformed into fibroblast which contain large amount of organelles which are necessary for the synthesis and excretion of protein needed to repair the tissue damage , also this cell is forming collagen fiber.
animal science general biology
? reticular cells
are like fiberoblast but usually large than it s they are form a network of reticular fibers .
? mesenchymal cells
are stem cells , resemble fibroblast in shape but smaller , these cells differentiate into other type cell of connective tissue .
? adipocytes or fat cells
are large cell their main function is storage of lipids , their cytoplasm is narrow rim around a large central lipid dropinglet , the flattened nucleus is squeezed into one side of cells .
? macrophages
are arise from precursor cell called monocytes originate in the bone marrow when they are released into the blood stream they are activity mobile and leave the blood stream to enter connective tissue where they differentiate into macrophage , they play an important role in body defense by phycocytosis .
? mast cells
are small , mobile connective tissue cells , commonly found near blood vessels , they cytoplasm of mast cell is filled with granules of histamine and heparin , their function in inflammation processes .
? lymphocytes and plasma cell
lymphocytes are small cells , their nucleus are round , the cytoplasm form narrow as rim around the nucleus ,in case of immunological reaction some lumphocytes may differentiated into plasma cell which produce antibodies .
? eosinophilic cells
are round or oval , large cell which contain large amount of ground in their cytoplasm . they originate in bone marrow , they enter connective tissue in inflammatory reaction where they phygocytose antigen – antibody complex .
connective tissue fibers
three type of fibers are found in connective tissue : collagen fiber , reticular fiber and elastic fiber .
fibroblast form all three types of fiber through the secretion of protein subunits that interact within the matrix .
animal science general biology
? collagen fiber : are long ,straight , and unbranched . these are the most common fibers in connective tissue proper . collagen fiber consist of a bundle of fibrous protein subunits wound together like the strands of a rope , acollagen fiber is flexible , but it is stronger than steel when pulled from either end .
? reticular fibers : contain the same protein subunit as collagen fibers , but they are arranged differently . these fibers are thinner than collagen fibers ,and they form a branching .
?elastic fiber : contain the protein elastin . elastic fiber are branched and wavy .after stretching , they will retun to their original length .they are rare but have important function , such as interconnect the vertebrae .
classification of connective tissue
connective tissue can be classified into tow categories as follow :
connective tissue
general connective tissue
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specialized connective tissue
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?mesenchyma con .t.
?areolar con . t.
? mucoid con .t .
?reticular con .t .
? adipose con .t .
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animal science general biology
?- general connective tissue or proper connective tissue
refers to connective tissue with many type of cells and fiber in syrupy ground substance . it is divided into :
?dense connective tissue:
distinguished by abundance of fibers incorporated within the matrix .this type of connective tissue are often called collagenous tissue because collagen fibers are the dominant fiber . tow type of dense connective tissue .
(a) dense irregular connective tissue :-
unarranged fibers in this type of tissue to provide strength and support to areas subjected to stresses such as dermis in skin.
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(b) dense regular connective tissue : -
the fibers are arranged parallel to each other , include :
1- white fibrous connective tissue such as tendon that join muscle to bone .
2- elastic connective tissue such as ligaments that join bone to bone .
? loose connective tissue : -
is relatively rich in cell and less fiber than dense connective tissue < it is classified into :
(a) mesenchyme connective tissue
is the first connective tissue to appear in the developing embryo and consider undifferentiated tissue , it consist of mesenchymal cell which inter connect by slender cell processes found in early embryo .
(b) areolar connective tissue
most widespread of all the connective tissue . this type may contain all the cell , fibers and clear jelly matrix . it is found in skin layer that separated the skin from deeper structure .
(c) mucoid connective tissue:
it is found in umbilical cord of embryo consist of fibroblast and less number of collagen fiber
(d) reticular connective tissue :
it is found in organs such as spleen ,live and lymph nodes ,fibroblasts & macrophages are associated with the reticular fibers .
animal science general biology
(e) adipose connective tissue :
specialized for the storage of lipids ,adipocytes account for most of the volume of adipose tissue.account for most of the volume of adipose tissue .two type of adipose tissue which derive their name frame color of the tissue (white and brown )and the number of lipid dropinglets found in the adipocytes.
adipocytes of which ,unilocular adipose tissue contain one large lipid dropinglet .adipocytes of brown ,multilocular contain many lipid dropinglets
white fibrous connective tissue
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areolar connective tissue
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المادة المعروضة اعلاه هي مدخل الى المحاضرة المرفوعة بواسطة استاذ(ة) المادة . وقد تبدو لك غير متكاملة . حيث يضع استاذ المادة في بعض الاحيان فقط الجزء الاول من المحاضرة من اجل الاطلاع على ما ستقوم بتحميله لاحقا . في نظام التعليم الالكتروني نوفر هذه الخدمة لكي نبقيك على اطلاع حول محتوى الملف الذي ستقوم بتحميله .