Cellular junctions in oral tissues Cej Dej

1. NAME:SYEDA HEBA GUL
CLASS NO.71
1st 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.

8. 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.

9. 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.

10. 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.

12. 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.

13. 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.

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

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

16. 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.

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

18. 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.