Decidua parietalis

General Information
Latin	decidua parietalis
Greek
TA98
TA2
FMA
Details
System	Reproductive system
Artery
Vein
Nerve
Lymphatic drainage
Precursor	Endometrium
Function	Support and protection of the developing embryo
Identifiers
Clinical significance
Notes

The decidua parietalis is a specialized layer of the endometrium, the inner lining of the uterus, that plays a crucial role during pregnancy. It is one of the three components of the decidua, the others being the decidua basalis and the decidua capsularis.

Structure

The decidua parietalis is formed from the endometrial lining of the uterus that is not directly involved in the implantation of the blastocyst. It lines the remainder of the uterine cavity and is distinct from the decidua basalis, which is located beneath the implanted embryo, and the decidua capsularis, which surrounds the embryo.

Histology

Histologically, the decidua parietalis is characterized by large, polygonal decidual cells, which are transformed stromal cells of the endometrium. These cells are rich in glycogen and lipids, providing a nutrient-rich environment for the developing embryo. The decidua also contains a variety of immune cells, including macrophages, natural killer cells, and T cells, which play roles in modulating the maternal immune response to the semi-allogeneic fetus.

Function

The primary function of the decidua parietalis is to provide structural support to the growing embryo and to participate in the formation of the maternal-fetal interface. It helps in the protection of the embryo from mechanical stress and contributes to the immunological tolerance of the fetus by the maternal immune system.

Role in Pregnancy

During pregnancy, the decidua parietalis undergoes significant changes to accommodate the growing fetus. As the pregnancy progresses, the decidua capsularis and decidua parietalis eventually fuse, obliterating the uterine cavity. This fusion is essential for the expansion of the amniotic sac and the growing fetus.

Clinical Significance

The decidua parietalis can be involved in various pathological conditions during pregnancy. Abnormalities in its development or function can contribute to complications such as placenta accreta, where the placenta abnormally adheres to the uterine wall, or preeclampsia, a condition characterized by high blood pressure and damage to other organ systems.

See Also

• Decidua basalis
• Decidua capsularis
• Endometrium
• Pregnancy
• Placenta

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