Search results
Results from the WOW.Com Content Network
The etymology of the term "freemartin" is uncertain: speculations include that "free" may indicate "willing" (referring to the freemartin's willingness to work) or "exempt from reproduction" (referring to its sterility, or to a farmer's decision to not bother trying to breed a freemartin, or both), or that it may be derived from a Flemish word for a cow which gives no milk and/or has ceased to ...
Udder of a cow. An udder is an organ formed of two or four mammary glands on the females of dairy animals and ruminants such as cattle, goats, and sheep. [1] An udder is equivalent to the breast in primates, elephantine pachyderms and other mammals.
They are the only accessory reproductive glands in male monotremes. Placental mammals usually have one pair of bulbourethral glands, [ 3 ] while male marsupials have 1–3 pairs. [ 3 ] [ 4 ] [ 5 ] Of all domesticated animals, they are absent only in dogs.
The reproductive system of an organism, also known as the genital system, is the biological system made up of all the anatomical organs involved in sexual reproduction. Many non-living substances such as fluids, hormones , and pheromones are also important accessories to the reproductive system. [ 1 ]
The female reproductive system includes the structures involved in ovulation, fertilization, development of an embryo, and birth. [3] Human female reproductive structures. These structures include: Ovaries; Oviducts; Uterus; Vagina; Mammary Glands; Estrogen is one of the sexual reproductive hormones that aid in the sexual reproductive system of ...
X 50. Membrana granulosa labeled at upper left. In the development of the urinary and reproductive organs, the oogonia become invaginated in the gonadal ridge. The embryological origin of granulosa cells remains controversial. In the 1970s, evidence emerged that the first cells to make contact with the oogonia were of mesonephric origin.
The egg cell is generally asymmetric, having an animal pole (future ectoderm).It is covered with protective envelopes, with different layers. The first envelope – the one in contact with the membrane of the egg – is made of glycoproteins and is known as the vitelline membrane (zona pellucida in mammals).
Gametogenesis is a biological process by which diploid or haploid precursor cells undergo cell division and differentiation to form mature haploid gametes.Depending on the biological life cycle of the organism, gametogenesis occurs by meiotic division of diploid gametocytes into various gametes, or by mitosis.