Search results
Results from the WOW.Com Content Network
Nine-week-old human embryo from an ectopic pregnancy. Organogenesis is the development of the organs that begins during the third to eighth week, and continues until birth. Sometimes full development, as in the lungs, continues after birth. Different organs take part in the development of the many organ systems of the body.
An embryo is the initial stage of development for a multicellular organism.In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male sperm cell.
Biochemically, pregnancy starts when a woman's human chorionic gonadotropin (hCG) levels rise above 25 mIU/mL. [5] Biologically, pregnancy starts at implantation of the fertilized egg. Human pregnancy can be divided into three trimesters, each approximately three months long: the first, second, and third trimester.
The process the mother experiences whilst carrying the fetus or embryo is referred to as pregnancy. The placenta connects the developing fetus to the uterine wall to allow nutrient uptake, thermo-regulation, waste elimination, and gas exchange via the mother's blood supply; to fight against internal infection; and to produce hormones which ...
In human pregnancy, prenatal development is also called antenatal development. The development of the human embryo follows fertilization , and continues as fetal development . By the end of the tenth week of gestational age , the embryo has acquired its basic form and is referred to as a fetus .
Implantation is the first stage of gestation, and, when successful, the female is considered to be pregnant. [3] An implanted embryo is detected by the presence of increased levels of human chorionic gonadotropin (hCG) in a pregnancy test. [3] The implanted embryo will receive oxygen and nutrients in order to grow.
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!
Diagram of the human fetal circulatory system. Oxygenated blood from the placenta is carried to the fetus by the umbilical vein, which will drain into the inferior vena cava (IVC) through the ductus venosus or the liver. [5]