 Dear students, in this topic we shall discuss the glands, their secretions and secretive mechanisms. A gland is a cell, a group of cell that secretes a particular chemical substance for use in the body or for discharge into the surroundings. The every animal has a large number of glands which differ in their structure and type of secretions. Secretions are the chemical substances which are synthesized by glandular cells. They are released from the gland in response to a particular relevant stimulus. The nature and amount of the secretion vary greatly among different glands. Based on the distance at which the glandular secretions act, the glandular secretions are of four types. Number one, autocrine secretions. Number two, paracrine secretions. Number three, endocrine secretions and number four, exocrine secretions. The autocrine secretions are those secretions which are produced by a gland or a cell and act on the cell itself. Such cells have autocrine receptors present on them. As a result, the substance produced causes changes and response in the same cell. The paracrine secretions act locally. They are produced by a cell and they affect the cells of nearby neighboring area. The example of paracrine secretions comes from the histamine which is released in an inflamed area and induces inflammatory response by the cells affected by some type of inflammation. The endocrine secretions are those secretions or those substances which are released into the bloodstream and they act on distant target tissues by traveling and circulating through the blood. Such secretions are usually called hormones which secrete a gland in the blood and the blood takes it to distant targets. The exocrine secretions are the substances which are produced by the gland and they are released from the gland by a duct. Such glands are ducted glands and the secretions are produced or released on the external epithelial surfaces. For example, digestive secretions, milk, tears, perspiration, fluids containing spams, these are all exocrine secretions. Dear students, now we shall discuss the secretive mechanisms. The substance to be exported out of the cell is stored in the form of secretive vesicles. These vesicles are released by three mechanisms. They are released as apocrine or merocrine or halocrine pattern. In apocrine release the secretive vesicles are gathered in the apical portion of the cell and this portion of the cell containing all the secretive vesicles is sloughed off from the cell. This is the part where the secretive vesicles are collected and the whole part of the cell is broken. In this way, the cell loses its large part or a large quantity of cytoplasm in this secretion but all the secretions come out of the cell. This method is found in memory glands during milk secretion. During merocrine release the secretive vesicles release their material by exocytosis. Secretive vesicles are produced in the cell membrane and the secretions come out of the cell. In this release, there is no loss of cytoplasm or any component of the cell. This method is the most common method of secretion. It is seen in sweat glands and many digestive glands. In halocrine release the cell synthesizes the material to be secreted and after this synthesis the cell ruptures and breaks up releasing the contents as a result cell is itself damaged. This method is observed in the sebaceous gland cells.