Decidua
Decidua is modified or specialized mucosal lining of endometrium during pregnancy.
Layers of Decidua
3 layers of decidua present;
1. Compact outer layer (stratum compactum)
Stratum compactum contain contain compact mass of decidual cells, gland ducts, dilated capillaries.
2. Intermediate spongy layer (stratum spongiosum)
Stratum spongiosum contains dilated uterine glands, decidual cells and blood vessels.
3. Thin basal layer (stratum basalis)
Stratum basalis is regeneration of mucus coat.
After the interstitial implantation of blastocyst into compact layer of decidua differentiated;
1. Decidua basalis or decidua serotina
Portion of decidua in contact with base of blastocyst.
2. Decidua capsularis
Covering the blastocyst.
3. Decidua parietalis or vera
Lining the rest of uterine cavity.
Growing ovum bulges towards uterine cavity space between decidua capsularis and decidua vera called decidual space gradually narrowed by 4th month.
Completely fusion of decidua capsularis with decidua vera.
Decidua basalis becomes maternal portion of placenta.
Function of Decidua
1. Site of implementation
2. Invasion of trophoblast
3. Supply nutrition to early implanted ovum.
4. Deeper penetration of trophoblast
5. Take part in formation of basal plate of placenta (maternal side of placenta).
