they are called ciliated epithelium . This ciliated type propels mucus by ciliary actions and it lines the small bronchioles, fallopian tubes and uterus. Nonciliated type lines most of the digestive tract, gall bladder and secretory ducts of glands. Pseudo-stratified epithelial cells are columnar, but unequal in size.
Although the epithelium is single layered yet it appears to be multi-layered because the nuclei lie at different levels in different cells. Hence, it is also called pseudostratified epithelium and XI Std Biology-Zoology Chapter- its functions are protection, secretion and absorption. Ciliated forms line the trachea and the upper respiratory tract. The non ciliated forms, line the epididymis, large ducts of a glands and tracts of male urethra Important epithelial tissue disorders: Eczema, Psoriasis, Epithelial carcinoma and severe asthma Glandular Epithelium Some of the cuboidal or columnar cells get specialized for secretion and are called glandular epithelium (Figure .
). They are mainly of two types: unicellular, consisting of isolated glandular cells (goblet cells of the alimentary canal ), and multicellular, consisting of cluster of cells ( salivary gland ). On the basis of the mode of pouring of their secretions, glands are divided into two categories namely exocrine and endocrine glands. Exocrine glands secrete mucus, saliva, earwax, oil, milk, digestive enzymes and other cell products.
These products are released through ducts or tubes. In contrast endocrine glands do not have ducts. Their secretions called hormones are secreted directly into the fluid bathing the gland. The exocrine glands are classified as unicellular and multicelluar glands.
The multicelluar glands are further classified based on the structure as simple and compound glands, based on their secretory units as tubular, alveolar (Acinus) and tubulo alveolar . Based on the mode of secretion exocrine glands are classified as merocrine, holocrine and apocrine . Glandular Epithelium Exocrine glands Endocrine glands Based on structure . Simple glands .
Compound glands Based on their secretory units Based on their mode of secretion Unicellular Multicellular . Tubular . Alveolar(Acinus) . Tubulo alveolar .
Merocrine . Holocrine . Apocrine 8QLFHOOXODU JODQG 0XOWLFHOOXDU JODQG Figure . Glandular