Glandular Epithelium Lecture Notes PDF

GLANDULAR EPITHELIUM Lec-2  CLASSIFICATION OF EXOCRINE GLANDS 1. According to the number of cells: a. Unicellular Glands- eg goblet cells B. Multicellular glands- submandibular salivary gland  CLASSIFICATION OF EXOCRINE GLANDS 2. According to their...

GLANDULAR EPITHELIUM Lec-2  CLASSIFICATION OF EXOCRINE GLANDS 1. According to the number of cells: a. Unicellular Glands- eg goblet cells B. Multicellular glands- submandibular salivary gland  CLASSIFICATION OF EXOCRINE GLANDS 2. According to their mode of secretion 1. MEROCRINE 2. HOLOCRINE 3. APOCRINE SECRETION CLASSIFICATION OF EXOCRINE GLANDS- 1. SEROUS 2. MUCOUS 3. ACCORDING 3. SERO-MUCOUS TO THE SECRETORY PRODUCT SEROUS GLANDS MUCOUS GLANDS  1. They have both mucous and serous secretory units. 2. Shaped as acini and tubules respectively 3. SEROUS DEMILUNES Clumps of serous cells at the ends of some mucous tubules appear as crescent-shaped structures SEROMUCOUS, COMPOUND TUBULOACINAR GLAND  MYOEPITHELIAL CELLS Stellate or spindle shaped cells. Located between the basal lamina and the basal pole of secretory cells. They have long processes FUNCTION To contract around the secretory or conducting portion of the gland and thus help propel secretory products out of the duct.  CLASSIFICATION OF EXOCRINE GLANDS 4. According to the shape of the ducts which transport the secretion A. Simple exocrine glands B. Simple branched exocrine glands C. Complex exocrine glands. EXOCRINE GLANDS- ACCORDING TO THE SHAPE OF THE DUCTS 2. 3. Tubular 4. Acinar 1. Simple Compound glands(short, (round, ducts ducts long, coiled) globular) SIMPLE GLANDS COMPOUND GLANDS  ENDOCRINE CELLS 1. Produce hormones 2. Hormones- polypeptide or lipid- derived factors that are released into the interstitial fluid 3. Paracrine signaling A cell targets a nearby cell, short distance to a neighboring cell. 4. Autocrine signaling: a cell targets itself, releasing a signal that can bind to receptors on its own surface.  Cells can transport certain ions against a concentration and electrical potential gradient. EXAMPLE TRANSPORT SODIUM PUMP ACROSS TRANSCELLULAR TRANSPORT- EPITHELIA Some epithelial cells actively transfer ions and fluid across the epithelium, from its apex to its base or vice-versa TRANSCYTOSIS  RENEWAL OF EPITHELIAL CELLS 1. Cells of epithelial tissue are renewed continuously by mitotic activity. 2. The renewal rate is variable 3. The replacement cells are produced by mitotic activity of self-maintaining adult stem cells. 4. They are located in sites called niches.  1. Both benign and malignant tumors of epithelial cells can be formed. CLINICAL 2. Carcinoma- malignant tumor APPLICATION ADENOCARCINOMA Malignant carcinoma of glandular epithelium  1. NEOPLASIA Abnormal growth of epithelial cells CLINICAL Reversible APPLICATION 2. METAPLASIA Abnormal transformation of epithelial cells  2015 Junqueira's Basic Histology Text and REFERENCES Atlas, 15th Edition, pages 84-90