Exocrine glands

Glandular tissue that have ducts that open onto a body surface or into a body cavity. Examples include sebaceous, sweat, and mammary glands. Salivary glands and certain glandular structures of the pancreas that secrete digestive enzymes are examples of exocrine glands secreting into a body cavity. The secretions of exocrine glands can be mucous (viscous), or serous (thin, watery). The ducts of exocrine glands may be simple straight tubes, or can be arranged as more complex branching tubes. Some of the more complex branching duct systems may terminate in multiple sac-like structures called acini giving them a "bunches of grapes" appearance.

Multicellular epithelial structures that specialize in synthesizing and secreting complex molecules. Glands are commonly classified by the mechanism they use to secrete their products:

Glandular Epithelium

Glandular Epithelium Columnar epithelium basic histology with goblet cells is called glandular epithelium. Some parts of the glandular epithelium consist of such a large number of goblet cells that there are only a few normal epithelial cells left. Columnar and cuboidal epithelial cells often become specialised as gland cells which are capable of synthesising and secreting certain substances such as enzymes, hormones, milk, mucus, sweat, wax and saliva. Basic histology Unicellular glands consist of single, isolated glandular cells such as the goblet cells. Sometimes a portion of the epithelial tissue becomes invaginated and a multicellular gland is formed. Multicellular glands are composed of clusters of cells. Most glands are multicellular including the salivary glands.

Transitional epithelium

Transitional epithelium in basic histology blog - Also called uroepithelium. Stratified epithelial tissue with unique dome-shaped surface cells giving it a cobblestoned appearance. Found exclusively in the urinary system (lining of bladder and ureter). They serve as a barrier preventing the exposure of underlying tissues to urine. They are also able to stretch in response to bladder filling. Basic histology

Pseudostratified epithelium

Pseudostratified epithelium - basic histology Intermediary between simple and stratified epithelium. Consists of one layer of irregularly shaped and sized cells attached to a basement membrane. Because these cells vary in height, their nuclei are at different levels, giving the appearance (under the microscope) of more than one layer of cells. Found in lining of the trachea, bronchi, pharynx, nasal cavity, and urethra in basic histology blog

Stratified Epithelium

Stratified epithelim in basic histology Where body linings have to withstand wear and tear, the epithelia are composed of several layers of cells and are then called compound or stratified epithelium. The top cells are flat and scaly and it may or may not be keratinised (i.e. containing a tough, resistant protein called keratin). The mammalian skin is an example of dry, keratinised, stratified epithelium. The lining of the mouth cavity is an example of an unkeratinisied, stratified epithelium.

Ciliated Columnar Epithelium

Ciliated Columnar Epithelium These are simple columnar epithelial cells, but in addition, they posses fine hair-like outgrowths, cilia on their free surfaces. These cilia are capable of rapid, rhythmic, wavelike beatings in a certain direction. This movement of the cilia in a certain direction causes the mucus, which is secreted by the goblet cells, to move (flow or stream) in that direction. Ciliated epithelium is usually found in the air passages like the nose. It is also found in the uterus and Fallopian tubes of females. The movement of the cilia propel the ovum to the uterus.