Search results
Results from the WOW.Com Content Network
A. Morula and B. cross section of a blastula displaying the blastocoel and blastoderm of early animal embryonic development. 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 morula is now watertight, to contain the fluid that the cells will later pump into the embryo to transform it into the blastocyst. In humans, the morula enters the uterus after three or four days, and begins to take in fluid, as sodium-potassium pumps on the trophoblasts pump sodium into the morula, drawing in water by osmosis from the ...
Only embryonic stem cells of the morula are totipotent: able to develop into any type of cell, including those of the placenta. Embryonic stem cells (ESCs) are pluripotent stem cells derived from the inner cell mass of a blastocyst, an early-stage pre-implantation embryo.
The morula then develops by cavitation to become the blastocyst, or in many other animals the blastula. Cell differentiation then further commits the morula's cells into two types: trophectoderm cells that surround the lumen and the inner mass of cells (the embryoblast). The inner cell mass is at the origin of embryonic stem cells. [15]
Fluid collects between the trophoblast and the greater part of the inner cell-mass, and thus the morula is converted into a vesicle, called the blastodermic vesicle. The inner cell mass remains in contact, however, with the trophoblast at one pole of the ovum; this is named the embryonic pole, since it indicates the location where the future ...
The zygote spends the next few days traveling down the fallopian tube dividing several times to form a ball of cells called a morula. Further cellular division is accompanied by the formation of a small cavity between the cells. This stage is called a blastocyst.
The trophoblast cells form tight junctions between them making the structure leakproof. Trophoblast cells have sodium pumps on their membranes, and pump sodium into the centre of the morula. This draws fluid in through osmosis causing a cavity to form inside the morula, and to increase in size. [2] The cavity is the blastocoel.
The division of blastomeres from the zygote allows a single fertile cell to continue to cleave and differentiate until a blastocyst forms. The differentiation of the blastomere allows for the development of two distinct cell populations: the inner cell mass, which becomes the precursor to the embryo, and the trophectoderm, which becomes the precursor to the placenta.