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The fetal membranes separate maternal tissue from fetal tissue at a basic mechanical level. The fetal membrane is composed of a thick cellular chorion covering a thin amnion composed of dense collagen fibrils. The amnion is in contact with the amniotic fluid and ensures structural integrity of the sac due to its mechanical strength.
It is the fetal heart and not the mother's heart that builds up the fetal blood pressure to drive its blood through the fetal circulation. Intracardiac pressure remains identical between the right and left ventricles of the human fetus. [15] The blood pressure in the fetal aorta is approximately 30 mmHg at 20 weeks of gestation, and increases ...
[4] [5] Before the placenta is formed and can take over, the yolk sac provides nutrition and gas exchange between the mother and the developing embryo. [ 6 ] At the end of the fourth week, the yolk sac presents the appearance of a small pear-shaped opening (traditionally called the umbilical vesicle ), into the digestive tube by a long narrow ...
Diagrams to show the development of male and female generative organs from a common type. A.—Diagram of the primitive urogenital organs in the embryo previous to sexual distinction. 3. Ureter. 4. Urinary bladder. 5. Urachus. cl. Cloaca. cp. Elevation which becomes clitoris or penis. i. Lower part of the intestine. ls.
The allantois (/ ə ˈ l æ n t oʊ ɪ s / a-LAN-toe-iss; [1] pl.: allantoides or allantoises) is one the extraembryonic membranes arising from the yolk sac.It is a hollow sac-like structure filled with clear fluid that forms part of the developing conceptus in an amniote that helps the embryo exchange gases and handle liquid waste.
Leonardo mistakenly depicted the cotyledons in the vascular walls of the human uterus that he had previously found in a cow uterus. [3] The other study, measuring 30.3×22 cm, shows female external genitalia , the supposed arrangement of abdominal muscles on the top right and fetus from different angles.
The uterus or womb is the major female reproductive organ. The uterus provides mechanical protection, nutritional support, and waste removal for the developing embryo (weeks 1 to 8) and fetus (from week 9 until the delivery). In addition, contractions in the muscular wall of the uterus are important in pushing out the fetus at the time of birth.
The enlarging uterus, growing fetus, placenta, amniotic fluid, normal increase in body fat, and increase in water retention all contribute weight gain during pregnancy. The amount of weight gain can vary from 5 pounds (2.3 kg) to over 100 pounds (45 kg).