Anaesthesia Fundamentals | Physiology | Functions of the Placenta

Functions of the Placenta
Session Overview
Description
This session will explore the functions of the placenta and will provide the necessary understanding for a doctor starting in obstetric anaesthesia.

Learning Objectives
By the end of this session you will be able to:

• Outline the development and structure of the placenta
• Explain the functions of the placenta including placental transport, hormone secretion and transfer of drugs

Prerequisites
Before commencing this session you should:

• Module 07b/Pregnancy/Physiology of the mother/Physiology of pregnancy and labour 1 (001-0706)
• Module 07b/Pregnancy/Physiology of the mother/Physiology of pregnancy and labour 2 (001-0707)

An understanding of the functions of the placenta is essential for any doctor working in obstetric anaesthesia.

The placenta is critical in the development and maintenance of a healthy fetus. It consists of maternal and fetal tissues and is composed of projections of fetal tissue (villi) that lie in maternal vascular spaces (intervillous spaces) (Fig 1).

Maternal blood in the intervillous spaces flows from spiral arteries which are branches of the uterine arteries. Venous drainage from intervillous spaces drains into uterine veins.

Deoxygenated fetal blood in the villi flows from two umbilical arteries in the umbilical cord and returns to the fetus as oxygenated blood via one umbilical vein.