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In developmental biology, the Hamburger–Hamilton stages (HH) are a series of 46 chronological stages in chick development, starting from laying of the egg and ending with a newly hatched chick. It is named for its creators, Viktor Hamburger and Howard L. Hamilton. Chicken embryos are a useful model organism in experimental embryology for a ...
Animal embryonic development. Diagram of stages of embryo development to a larval and adult stage. In developmental biology, animal embryonic development, also known as animal embryogenesis, is the developmental stage of an animal embryo. Embryonic development starts with the fertilization of an egg cell (ovum) by a sperm cell, ( spermatozoon ...
Anatomical terminology. [ edit on Wikidata] Gastrulation is the stage in the early embryonic development of most animals, during which the blastula (a single-layered hollow sphere of cells ), or in mammals the blastocyst, is reorganized into a two-layered or three-layered embryo known as the gastrula. [ 1]
In the chick embryo, somites are formed every 90 minutes. In the mouse the interval is 2 hours. [7] For some species, the number of somites may be used to determine the stage of embryonic development more reliably than the number of hours post-fertilization because rate of development can be affected by temperature or other environmental factors.
Carnegie stages. In embryology, Carnegie stages are a standardized system of 23 stages used to provide a unified developmental chronology of the vertebrate embryo . The stages are delineated through the development of structures, not by size or the number of days of development, and so the chronology can vary between species, and to a certain ...
Hans Spemann. Viktor Hamburger (July 9, 1900 – June 12, 2001) [ 1][ 2] was a German-American professor and embryologist. His collaboration with neuroscientist Rita Levi-Montalcini resulted in the discovery of nerve growth factor. [ 3] In 1951 he and Howard Hamilton published a standardized stage series to describe chicken embryo development ...
Blastulation. Blastulation is the stage in early animal embryonic development that produces the blastula. In mammalian development, the blastula develops into the blastocyst with a differentiated inner cell mass and an outer trophectoderm. The blastula (from Greek βλαστός ( blastos meaning sprout )) is a hollow sphere of cells known as ...
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 ...