Write 3 pages with APA style on CELLULAR PATHOLOGY- Staining protocols. (McGavin and Zachary 2006). Fig1: Periodic acid Schiff stain (PAS) of kidney. (McGavin and Zachary 2006). PAS staining is based on the monosaccharide present in the compounds. In the PAS reaction, the glycogen is digested using the diastase enzyme. The deposited glycogen is then treated with PAS. PAS breaks the 1, 2 – glycol linkages yielding aldehydes. The presence of glycol is identified by the Schiff’s reagent. After the treatment, when viewed under the microscope, glycogen will appear as vacuoles present in the cytoplasm of the cell. The glycogen molecule has irregular shapes with distinct nucleus. (McGavin and Zachary 2006). Glycogen storage diseases are easily identified by performing biopsy of a portion of the liver. Fig 2: PAS staining of the liver cells showing the hepatocytes filled with glycogen. (Schiff, Maddrey, and Sorrell, 2011). The second figure shows the PAS with diastase digestion. It is observed that the cells have clear vesiculated cytoplasm. Basement membrane: Basement membranes are the extracellular protein matrix with support tissues. The basement membrane cells have epithelial and muscle cells. Basement membrane helps to bind the epithelia tissue to the supporting tissue and also a metabolic support. Epithelial cells growth and differentiation is controlled by the basement membranes.