**3. Functions**

**1.** Transfer of nutrients and waste products between the mother and the fetus. In this respect, it attributes to the following functions:


**Figure 4.** Blood supply of placenta.

become larger and more toward the periphery of the villus. In the third trimester, the villi are much smaller in diameter, and the cytotrophoblasts are irregular and thinned out. The fetal

The placenta, at term, is almost a circular disc with a diameter of 15–20 cm and a thickness of about 3 cm at its center [2]. It feels spongy and weighs about 500 g, the proportion to the weight of the baby being roughly 1:  6 at term and occupies about 30% of the uterine wall. It

• The fetal surface is covered by the smooth and glistening amnion with the umbilical cord

• The maternal surface is rough and spongy. It consists of 15–20 lobes or cotyledons which are limited by fissures. Each fissure is occupied by the decidual septum which is derived

The placenta consists of two plates. The chorionic plate lies internally. It is lined by the amniotic membrane. The umbilical cord is attached to this plate. The basal plate lies to the maternal aspect. Between the two plates lies the intervillous space containing the stem villi with their branches, the space being filled with maternal blood. A mature placenta has a volume of about 500 mL of blood, 350 mL being occupied in the villi system and 150 mL lying in the

**1.** Transfer of nutrients and waste products between the mother and the fetus. In this respect,

presents two surfaces, fetal and maternal, and a peripheral margin (**Figure 3**) [2].

vessels are dilated and lie just below the thinned out trophoblasts.

attached at or near its center [2].

it attributes to the following functions:

from the basal plate [2].

**Figure 3.** Placenta at term.

4 Placenta

intervillous space [2].

**3. Functions**
