Placental barrier

Definition

The placental barrier is a selective membrane in the placenta that regulates the exchange of substances between maternal and fetal blood. It acts as a protective filter to prevent harmful pathogens and toxins from reaching the fetus while allowing essential nutrients and gases to pass through.

5 Must Know Facts For Your Next Test

1. The placental barrier consists of several layers, including trophoblast cells, connective tissue, and fetal capillary endothelium.
2. It allows the passage of antibodies like IgG from mother to fetus, providing passive immunity to the newborn.
3. The effectiveness of the placental barrier can be compromised by certain infections such as cytomegalovirus (CMV) and toxoplasmosis.
4. Small molecules like oxygen and carbon dioxide can easily diffuse across the placental barrier, but larger molecules are selectively transported.
5. The barrier's function is crucial for fetal development and immune system priming before birth.

Review Questions

Related terms

Trophoblast: Cells forming the outer layer of a blastocyst which provide nutrients to the embryo and develop into a large part of the placenta.

Passive Immunity:

Short-term immunity acquired by transfer of antibodies from another individual, such as from mother to fetus via placenta.

Cytomegalovirus (CMV):

A type of herpesvirus that can be transmitted from mother to fetus, potentially crossing an impaired placental barrier.