Erythrocyte (Red blood corpuscles) are highly differentiated and specialized for the function of transporting oxygen. In the lower vertebrates, the erythrocyte is nucleated but in mammals, it loses it nucleus, Golgi apparatus, mitochondria and centroiles before entering blood stream. The erythrocytes are acidophilic biconcave discs and round in all mammals except in camel and llama […]

Blood is the connective tissue consisting of free cells and a fluid intercellular substance or plasma. The structural elements of Mammalian blood include red blood corpuscles (erythrocytes), white blood corpuscles (leucocytes) and blood platelets.

Bone is richly supplied with blood vessels and nerves which pass into it form the periosteum. An artery, the medullary artery runs through the nutrient canal, through the nutrient foramen into the marrow cavity. In its course through compact bone, the branches of the medullary artery communicate with the vessels of the Haversian canal. The

Bone marrow is a soft tissue which occupies the medullary cavity of the long bones and the space between trabeculae of spongy bone. It consists of a delicate reticular connective tissue in the meshes of which are many kinds of cells. Two varieties of marrow are seen, red and yellow. Red marrow: It is the

Periosteum is a fibrous membrane investing the bones except at their articular surfaces. It consists of two layers, the outer of which is composed of course fibrous connective tissue containing few cells but numerous blood vessels and nerves. The inner layer is more cellular and less vascular and contains many elastic fibres. In the growing

Cancellated bone consists of a network of columns of lamellae enclosing spaces which contain bone marrow. There are no Haversian systems.

This is composed of numerous systems of concentrically arranged bony lamellae, around a central canal, the Haversian canal, which run longitudinally and encloses blood vessels. Each concentric system is known as a Haversian system or Osteon. Haversian canals of adjacent systems are inter connected by transverse channels and volkmann’s canals connect haversian canals with periosteal

Bone or osseous tissue consists of cells, collagenous fibers, and an intercellular matrix of organic substances. The organic matrix is chiefly made up of osseo mucoid and in this matrix, collagen fibres are embedded and the fibrils form a major portion of the intercellular substance. The inorganic matter is composed of calcium phosphate, calcium carbonate

Surface of cartilage is invested by a connective tissue membrane called perichondrium which consists of an inner chondrogenic and outer fibrous layer.

Ground substance of cartilage appears homogenous in fresh condition or in ordinary preparations. Only the walls of the lacunae stand out as mere refractive rings intensely staining with basic dyes. These rings are called capsules. These are not of the nature of cell membranes but represent considerations of the matrix surrounding the cells.  The ground substance