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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 ...
Human growthand development. Human fertilization is the union of an egg and sperm, occurring primarily in the ampulla of the fallopian tube. [1] The result of this union leads to the production of a fertilized egg called a zygote, initiating embryonic development. Scientists discovered the dynamics of human fertilization in the 19th century.
The hormonal theory of sexuality holds that, just as exposure to certain hormones plays a role in fetal sex differentiation, such exposure also influences the sexual orientation that emerges later in the individual. Prenatal hormones may be seen as the primary determinant of adult sexual orientation, or a co-factor.
Uterus. The uterus (from Latin uterus, pl.: uteri) or womb ( / wuːm /) is the organ in the reproductive system of most female mammals, including humans, that accommodates the embryonic and fetal development of one or more embryos until birth. [ 1] The uterus is a hormone -responsive sex organ that contains glands in its lining that secrete ...
Anatomical terminology. [ edit on Wikidata] In placental mammals, the umbilical cord (also called the navel string, [1] birth cord or funiculus umbilicalis) is a conduit between the developing embryo or fetus and the placenta. During prenatal development, the umbilical cord is physiologically and genetically part of the fetus and (in humans ...
Fetal position ( British English: also foetal) is the positioning of the body of a prenatal fetus as it develops. In this position, the back is curved, the head is bowed, and the limbs are bent and drawn up to the torso. A compact position is typical for fetuses. Many newborn mammals, especially rodents, remain in a fetal position well after birth.
Immune tolerance in pregnancy or maternal immune tolerance is the immune tolerance shown towards the fetus and placenta during pregnancy. This tolerance counters the immune response that would normally result in the rejection of something foreign in the body, as can happen in cases of spontaneous abortion. [ 1][ 2] It is studied within the ...
Thumb sucking. Thumb sucking is a behavior found in humans, chimpanzees, captive ring-tailed lemurs, [1] and other primates. [2] It usually involves placing the thumb into the mouth and rhythmically repeating sucking contact for a prolonged duration. It can also be accomplished with any organ within reach (such as other fingers and toes) and is ...