Harlem Renaissance - Visual Art, Creativity, Expression: Many Black painters and sculptors moved to Paris in the 1920s but returned to the United States during the Great Depression
Stem cell, an undifferentiated cell that can divide to produce some offspring cells that continue as stem cells and some cells that are destined to differentiate (become specialized). Stem cells are an ongoing source of the differentiated cells that make up the tissues and organs of animals and plants.
In vitro fertilization (IVF), medical procedure in which mature egg cells are removed from a woman, fertilized with male sperm outside the body, and inserted into the uterus of the same or another woman for normal gestation. Although IVF with reimplantation of fertilized eggs (ova) has long been
Human reproductive system - Female Anatomy, Hormones, Reproduction: The female gonads, or sexual glands, are the ovaries; they are the source of ova (eggs) and of the female sex hormones estrogens and progestogens. The fallopian, or uterine, tubes conduct ova to the uterus, which lies within the lesser or true pelvis. The uterus connects through the cervical canal with the vagina. The vagina opens into the vestibule about which lie the external genitalia, collectively known as the vulva. The female external genitalia include the structures placed about the entrance to the vagina and external to the hymen, the membrane across the entrance to the vagina. They are the
Human reproductive system - Uterus, Ovaries, Hormones: The uterus, or womb, is shaped like an inverted pear. It is a hollow, muscular organ with thick walls, and it has a glandular lining called the endometrium. In an adult the uterus is 7.5 cm (3 inches) long, 5 cm (2 inches) in width, and 2.5 cm (1 inch) thick, but it enlarges to four to five times this size in pregnancy. The narrower, lower end is called the cervix; this projects into the vagina. The cervix is made of fibrous connective tissue and is of a firmer consistency than the body of the uterus. The two fallopian tubes