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e. Human embryonic development or human embryogenesis is the development and formation of the human embryo. It is characterised by the processes of cell division and cellular differentiation of the embryo that occurs during the early stages of development. In biological terms, the development of the human body entails growth from a one-celled ...
Gestational age: 3 weeks and 0 days until 3 weeks and 6 days old. 22–28 days from last menstruation. Embryonic age: Week nr 2. 1 week old. 8–14 days from fertilization. Trophoblast cells surrounding the embryonic cells proliferate and invade deeper into the uterine lining. They will eventually form the placenta and embryonic membranes.
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. The next period is that of fetal development where ...
Embryo. 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. The resulting fusion of these two cells produces a single-celled zygote that undergoes ...
Nilsson in 1946 at the Bromma, Stockholm airport. Lennart Nilsson (24 August 1922 – 28 January 2017) [1] was a Swedish photographer noted for his photographs of human embryos and other medical subjects once considered unphotographable, and more generally for his extreme macro photography. He was also considered to be among Sweden ’s first ...
A human fetus, attached to placenta, at three months gestational age. In humans, the fetal stage starts nine weeks after fertilization. [7] At this time the fetus is typically about 30 millimetres (1 + 1 ⁄ 4 in) in length from crown to rump, and weighs about 8 grams. [7] The head makes up nearly half of the size of the fetus. [8]
The initial stages of human embryogenesis. Parts of a human embryo. Ontogeny (also ontogenesis) is the origination and development of an organism (both physical and psychological, e.g., moral development [1]), usually from the time of fertilization of the egg to adult. The term can also be used to refer to the study of the entirety of an ...
Cardiac activity is visible beginning at approximately 5 weeks of pregnancy. The human heart begins beating at a rate near the mother's, about 75-80 beats per minute (BPM). The embryonic heart rate (EHR) then accelerates linearly for the first month of beating, peaking at 165-185 BPM during the early 7th week, (early 9th week after the LMP).