Placental Physiology Flashcards
What is the Decidua?
What are it’s (4) parts?
Decidua: The endometrium of the gravid (pregnant) Uterus
Four parts;
- Basalis: Maternal part of the placenta
- Capsularis: Covers conceptus
- Parietalis: rest of the endometrium
- Reflexa: Junction between capsularis & Parietalis
Around what day does the Chorionic Villi begin to develop?
Day 13
Until the 8th week, the entire chorionic sac is covered with Villi. What occurs that changes this?
The Chorionic Sac grows and compresses the villi of Decidua capsularis. Only the part associated with Decidua Basalis retain it’s villi.
This results in (2) types of chorion;
- Chorion Frondosum: Villous chorion
- Chorion Laeve: Bare (smooth) chorion
What are the (2) components of the Placenta?
- Fetal part; Develops from the Chorion Frondosum
- Maternal part; develops from the endometrium (functional layer decidua basalis)
What is the function of the placenta? (5)
- Protection
- Nutrition
- Respiration
- Excretion
- Hormone Production
At term, what are the (3) layers of the Placental membrane?
- Syncytiotrophoblast
- Connective Tissue
- Endothelium of the capillaries
What is vasculosyncytial placental membrane?
Sites of the placental membrane in which the syncytiotrophoblast is in direct contact with the endothelium of the capillaries.
What are the (4) mechanisms of Placental transport?
- Simple Diffusion
- Facilitated Diffusion
- Active Transport
- Pinocytosis
Describe the layers/structures of the placental barrier from maternal side to fetus side.
- Intervillous space (w/ blood)
- Syncytiotrophoblast
- Cytotrophoblast
- Basement Membrane
- Connective tissue
- Fetal capillary
What is preclampsia?
Preclampsia is a pregnancy complication due to underdeveloped arteriovenous shunts resulting in narrower uterine arteries (thus higher resistance). It is characterized by high blood pressure.
What are the (3) primary symptoms of preclampsia?
- High Blood Pressure
- Swelling of hands & feet
- Protein in Urine
What is the incidence of Preclampsia?
Preclampsia affects 2-8% of pregancies worldwide.
What other diseases may increase the risk of preclampsia?
- Chronic Hypertension
- Chronic Renal Disease
- Collagen Vascular Disease
- Pregestational Diabetes Mellitus
When does preclampsia usually occur?
What if it occurs earlier?
Usually, preclampsia occurs after 32 weeks. If it occurs earlier, it is associated with worse outcomes.
What are the Immunogenic risk factors for Preeclampsia?
- Nulliparous (woman who has never given birth)
- Previous preeclampsia
- Multiple Gestation
- Abnormal Placentation
