ANATOMY, EMBRYO

Anatomical model of the female reproductive organs during pregnancy (embryo at one month).
At five weeks of pregnancy, the womb has reached the size of a tangerine; the embryo measures 6 mm and weighs less than 1 g. It is curved in shape, has a large head due to brain growth, a ventral protusion due to heart formation, and a tail. The internal organs have begun to take form, the buds of the four limbs have begun to grow and the neural tube, anlage of the future nervous system, becomes visible. The face begins to emerge with the anlages of the eyes, ears and nose.
The embryo (10) floats in the amniotic fluid that fills the amniotic cavity. The latter is surrounded by a membrane, the amnion (11, white). The embryo is linked to the chorion (8a, mauvish grey) through a primitive umbilical cord, the connective stalk (9). The uterine cavity is surrounded by the decidua (red), tissue resulting from transformations in the uterine endometrium (7). The decidua is divided into basal (8b, red, between the chorion and the uterus), capsular (between the embryo and the uterine cavity, white) and parietal deciduas (14, red, not in contact with the embryo). These areas are defined according to their position relative to the site of ovum implantation.
The infundibula (4, red), bordered with fringe-like structures, of the Fallopian tubes are situated over each ovary (yellow), which itself is connected to the womb through its own specific ligament. Each Fallopian tube is linked to a duct (pink) leading to the interior of the uterine cavity.