Connective Tissue:

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Location: widely found throughout the body and found in between different tissues and organs. Origin: from the embryonic mesoderm. Structure: composite structure and comprises cells, fibres and matrix. Cells are variously shaped cells lying wide apart in a large amount of nonliving intercellular or extracellular material, Fibres found scattered in between the cells, nonliving products of the cells and form the extracellular material, Matrix: nonliving, amorphous, transparent substance which permeates the tissue as a whole and which varies from a liquid consistency in blood to solid in a bone.

Types of connective tissue:

Image showing types of connective tissue.

Image Showing Types of Connective Tissue.

Image showing types of connective tissue.

Proper connective tissue:

Areolar tissue: simplest and the most widely distributed connective tissue found in the body of animals. Cells are forming the tissue are; (i) Fibroblasts-form the yellow (elastin) and white (collagen) fibres in the matrix and flattened and spindle shaped and contains an oval nucleus, (ii) Macrophages- polymorphic cells capable of amoeboid locomotion and help in engulfing bacteria and micro pathogens, (iii) Mast cell- Secret heparin (helps in clotting of blood) and histamine (released tissues when its injured or disrupted), (iv) Plasma cells- products of mitotic cell division by migratory lymphocytes, (v) Chromatophores- present at the skin and the eye, cells are much branched and packed, (vi) Fat cells- contains a large lipid droplet which fills the bulk of the cell, (vii) Mesenchyme cells- act as reserve of undifferentiated cells for the tissue.

Adipose tissue: It has specialized cells strong fat called adipose cells, has no specific matrix of its own and help in forming paddings.

Fibrous tissue: It is mainly made up of fibroblasts, it forms tendons and ligaments.

Supporting connective tissue:

Cartilage: Structure: hard but flexible tissue, consisting of cells embedded in a flexible matrix of chondrin. Cartilage develops from the mesenchyme. The matrix of cartilage is deposited by cells called chondroblasts and possesses many fibrils mostly made up of collagen. Eventually the chondroblasts become enclosed in spaces called lacunae. The cartilage may be elastic whose matrix has yellow fibres as in pinna of ear. The matrix of cartilage lacks the blood vessels and hence the exchange of materials between the chondrocytes and matrix is by diffusion only. Function: highly adapted to resist any strains that are placed upon it, matrix of cartilage is compressible and elastic and is able to absorb mechanical shocks which frequently occur between the articular surfaces of bones and collagen fibrils resist any tension which may be imposed on the cartilage. According to the composition of the matrix, the cartilage has been four types; Hyaline cartilage, Elastic cartilage, Fibrous cartilage and Calcified cartilage.

Bone: Matrix is composed of ossein, also contains salts of calcium, phosphorus and magnesium. Matrix in mammalian ling bones is arranged in concentric rings. The osteocytes lay the lamellae. Osteocytes give out branched processes which join with those of the adjoining cells. Some bones have a central cavity which contains a tissue that produces blood cells. The substance contained in the bone cavity is called bone narrow. Bones are two types; spongy and compact. In spongy bone, bone cells are irregularly arranged. Such bones are found at the ends of the of long bones. In the compact bones, cells are arranged in circles or lamellae around a central canal-the Haversian canal. Function: give shape to the body, provide attachment to the muscles and protect the vital organs of thorax as well as brain, also serve metabolic functions.

Fluid connective tissue:

Blood and Lymph are the two forms of the fluid connective tissue. Blood- is a type of alkaline, slightly saline, red coloured, liquid connective tissue and is the main circulatory medium in the body of mostly all vertebrates and some invertebrates and is complex of blood cells and plasma. Plasma forms the matrix. The blood cells; (i) red blood cells-transport O2 and CO2 (ii) white blood cells-function in defence against bacteria, viruses and other invaders (iii) Platelets-help in the clotting of blood.

Plasma is the liquid part of blood. It is straw coloured and contains 9-12 water and 8-9 organic and inorganic materials. The organic substances include various types of blood protein and waste materials. The organic part contains different minerals like sodium, potassium, iron, calcium, magnesium etc.

Image showing different types of connective tissue.

Image Showing Different Types of Connective Tissue.

Image showing different types of connective tissue.

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