Golgi Apparatus
Def: -The secretory system of the cell [Named after histologist Camillo Golgi who discovered it in 1898]
Well developed in secretory cells
L.M: -Not stained by H&E due to high lipid content in its membranes ® Gives pale area in cytoplasm called “Golgi ghost” or “–ve Golgi image” also
E.M: >>-Many flat membranous saccules, Stacked over each other >>-All saccules contain enzymes and proteins being processed >>-Located near the nucleus >>-Each saccule has two faces
Immature (Cis) face: Receives transport vesicles from rER
Mature (Trans) face: The shipping area that gives two types of vesicles
Types of vesicles: >>1-Secretory vesicles for exocytosis >>2-Lysosomes
N.B: Secretory granules: >>-Granules containing concentrated secretory products [up to 200 times than those in rER] until released by exocytosis >>-Zymogen granules: Secretory granules in pancreatic cells with dense contents of digestive enzymes
Functions of Golgi Apparatus: Completes the function of rER >>1-Concentration and packaging of proteins formed by rER >>2-Chemical modification of proteins >>3-Discharge of secretory vesicles ® Secretions >>4-Formation of lysosomes & isolation of their enzymes >>5-Maintenance of cell membrane & surface coat
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