In Elastic Cartilage elastic fibers are present and embedded in the matrix. These fibers branch and run in all directions and anastomose to form a dense network. In the peripheral layers, the fibres are thin and the network wide meshed. In the deeper portions, they are thicker and more closely packed. Elastic cartilage is present […]
Hyaline cartilage appears as a bluish-white translucent mass when fresh. It forms the articular cartilage of joints, the costal cartilages and cartilages of nose, larynx trachea and bronchi. In the foetus nearly the entire skeleton is first laid down as hyaline cartilage and later replaced by osseous tissue in the formation of bone. The tissue
Cartilage consists of the cells termed as chondrocytes, matrix (ground substance) and fibres. The matrix is solid and has marked elastic properties. It withstands considerable pressure and tension. According to the nature and visibility of fibrillar elements, cartilage is subdivided into three varieties: Hyaline Elastic Fibrous In these, hyaline cartilage is the most widely distributed
Certain glands are lacking in ducts and are termed endocrine glands. The endocrine glands secrete specific chemical substance called hormones which have specific effects on the other tissue or organs of the body e.g., thyroid, parathyroid, pituitary etc. The secretions of these glands are conveyed directly into the blood stream. To facilitate this endocrine glands have
Based on the consistency of the secretion, glands are classified into Serous, Mucous and Mixed glands. Serous glands produce a whey-like serous secretion. Mucous gland produces a slightly more viscid fluid. The glands that secrete mucin, glycoprotein which when mixed with water become mucous are termed as mucous glands. Any gland that produces a mixture of serous
Glands may be classified as cytogenous and non-cellular based on the nature of secretion Cytogenous gland produces living cells as their secretion. Eg. Testis, Ovary. Non-cellular glands are further classified into serous, mucous and mixed glands based on the consistency of their secretion
Based on the mode of secretion classification is based on the manner in which the secretory cells of the glands elaborate their secretion. Based on this glands are classified into Holocrine, merocrine and apocrine gland. In holocrine glands, the secretory products are accumulated in the cytoplasm of a cell, which disintegrates fully and constitutes the secretion secreted
Glands are classified into Simple and compound glands on based on the ductular system The ductular system of a gland may consist of simple epithelial tube draining a secretory unit and opening at the epithelial surface or it may be in the form of an extensively branched system, the initial smallest ducts draining the secretory
Based on the shape of the secretory unit- If the secretory units are tubular in shape it is a tubular gland. If secretory units are more rounded, then they are called alveolar or acinar glands. Glands which have characteristics of both these, or which have tubular portions with terminal alveoli, are called tubulo-alveolar glands.
The exocrine gland consists of a secretory portion and a duct. The secretory portion is arranged as a cluster of secretary cells known as a secretory unit, which has a central lumen, which opens into the first portion of the ductular system. The exocrine glands can be classified in several different ways based on the
