Vertebrate Development : Life cycles and experimental techniques Flashcards
(26 cards)
Antero-posterior axis
Main body axis of vertebrates
Somites
somite is a division of the body of an animal or embryo, are bilaterally paired blocks of paraxial mesoderm that form along the head-to-tail axis of the developing embryo in segmented animals
Cleavage
rapid cell divisions by which the embryo becomes divided into a number of smaller cells
Gastrulation
Set of cell movements that generates the three germ layers, ectoderm, mesoderm, and endoderm
Phylotypic stage
Stage of the embryo when the neural tube, somites, notochord, and head structures are present
Notochord
transient stiff, rod-like cellular structure in vertebrate embryos that runs from head to tail and lies centrally beneath the neural tube. It is derived from mesoderm and its cells eventually become incorporated into the vertebral column
Axial Structures in Vertebrates
notochord, neural tube, somites and vertebral column
What eventually happens the cells of the Notochord?
They are incorporated into the vertebral column that forms the spine
From which germ layer do somites develop?
Mesoderm
What major differences in development are there between the 5 main model organisms (zebra fish, xenopus, mouse, chick, human)
How and when axis are set up and how germ layers are established
What is the main reason for the differences in embryonic development across model organisms
differing modes of reproduction and the consequent form of the early embryo
Extra-embryonic membranes
membranes external to the embryo proper that are involved in its protection and nutrition, In mammals they include the amnion, chorion, and placental tissues
Amniotes
Organisms such as birds and mammals that form the amniotic extra-embryonic membrane
Anamniotes
Organisms such as fish and amphibians that do not form the extra-embryonic membranes
How are the stages of Development classified?
By the development of main features rather than by time after fertilization
What is the great advantage to using Xenopus as a Model Organsim?
Fertilized eggs are easy to obtain
Animal Region
In eggs of amphibians, the hemispherical end of the egg where the nucleus resides, away from the yolk. The most terminal part of this region is the animal pole, which id directly opposite the vegetal pole at the other end of the egg
Animal Cap
The pigmented animal half of the Animal Region of Xenopus
Animal-Vegetal axis
Axis that runs from the animal pole to the vegetal pole
Blastomeres
Cells deriving from cleavage divisions
In which half of the Xenopus embryo is cleavage slower?
Yolky Vegetal Half
Marginal Zone
Belt like region of presumptive mesoderm at the equator of the late blastula of an amphibian embryo. Gives rise to the Mesoderm
Which region gives rise to the endoderm in Xenopus?
Vegetal Region
Which region gives rise to the ectoderm in Xenopus?
Animal Region
