junctions in oral biology by Syeda Heba.pptx

All the junctions related with teeth and it's surrounding structures are discussed.

1. JUNCTIONS IN ORAL BIOLOGY NAME:SYEDA HEBA GUL CLASS NO.71 1 st YEAR BDS

2. LEARNING OBJECTIVES What are Junctions? Functions of Junctions. Types of Junctions.

3. JUNCTION DEFINITION: A point where two or more things meet. OR Connections between cells.

4. FUNCTIONS: Link cells to each other in tissue. Regulate tissue homeostasis in critical cell processes like cell proliferation and migration.

5. TYPES: A.JUNCTIONS IN ORAL EPITHELIUM: 1.TIGHT JUNCTION 2.ADHESIVE JUNCTION 3.COMMUNICATING(GAP) JUNCTION B.JUNCTIONAL EPITHELIUM. C.MUCOGINGIVAL JUNCTION. D.JUNCTIONS IN TOOTH: 1.DENTINO-ENAMEL JUNCTION 2.CEMENTO-ENAMEL JUNCTION 3.CEMENTO-DENTINAL JUNCTION

6. A.JUNCTIONS IN ORAL EPITHELIUM: 1.TIGHT JUNCTION: In tight junction the cells are held in close contact by presence of transmembrane proteins Proteins include occludin , claudin family and junctional adhesion molecule. Tight junctions control the passage of material through intercellular spaces i.e. from interstitium to lumen.

7. SIGNIFICANCE OF TIGHT JUNCTION They tightly hold the cells together. They are designed to act as diffusion barrier. They are placed at the apical surface of cell.

8. 2.ADHESIVE JUNCTION: Holds the cells together or anchor cells to the matrix. Cell-cell adhesive junction is at the distance of 20nm. They are important in cell signaling.

9. TYPES CELL-MATRIX OR HEMIDESMOSOMES CELL-CELL OR DESMOSOMES They resist more the shearing and abrasive forces and are stronger than adherens junction. Basically they help in the formation of basement membrane.

10. 2.GAP JUNCTION: Are designed to allow cell to cell communication. Cell membranes are 2-3nm apart. Transmembrane protein: connexon family. These form aqueous channels between the cytoplasm of adjacent cells.

11. B.JUNCTIONAL EPITHELIUM: A single or multiple layers of non-keratinizing cells adhering to the tooth surface at the base of gingival sulcus. Its length:0.25-1.35mm. Extends from cemento -enamel junction to the gingival sulcus.

12. FUNCTIONS: Acts as a barrier. Provide attachment to the tooth. Secretes antimicrobial peptides. Allows Gingival Crevicular Fluids(GCF) flow.

13. C.MUCOGINGIVAL JUNCTION: The area of union of gingiva and alveolar mucosa. It remains stationary throughout life.

14. D.JUNCTIONS IN TOOTH: 1.DENTINO-ENAMEL JUNCTION. Between dentin and enamel. Seen as scalloped boarder with convexities of scallops directed towards dentin. This increase the surface area and adherence between two tissues.

15. 2.CEMENTO-ENAMEL JUNCTION: Junction between cementum and enamel. Also called cervical line. Not visible clinically. Covered by gingiva.

16. 3.CEMENTO-DENTINAL JUNCTION: Junction between cementum and dentin. This attachment is quite firm. 2-3 micrometer wide. Smooth in permanent teeth and scalloped in primary.