C5: Cleavage

in embryology, it is the first few cellular divisions of a zygote (fertilized egg)

describe the first three dvison of a zygote.

these early divisions produce separate cells called __

the rapid, multiple rounds of cell division are termed __

after the cleavage has produced over 100 cells, the embryo is called a ___

the __ is usually a spherical layer of cells (___) surrounding a fluid-filled or yolk-filled cavity (the ___)

mammals at this stage (cleavage has produced over 100 cells) form a structure called the ___, characterized by an ___ that is distinct from the surrounding blastula

each cell within the blastula is called a __

when the embryo consists of approximately 16 cells, it is called a ___ (from the Latin word meaning “___”)

starting after the eight-cell stage, the embryos of placental mammals enter into a phase called ___

compaction is mediated by concentration of calcium (Ca++)-activated cell adhesion molecules (such as ___), in a ring around the __ surface of the ___

through the activity of a ____, Na+ and water (H2O) move across the epitheliumlike outer blastomeres and accumulate in spaces among the inner blastomeres

the process wherein Na+ and water (H2O) move across the epitheliumlike outer blastomeres and accumulate in spaces among the inner blastomeres is called ___

the cavitation process takes about __ days after fertilization

the fluid-filled space is known as ___

once cavitation occurs, and a blastocoeleis formed, the embryo as a whole is known as a ___

the ___ stage, the embryo, which is still surrounded by the zona pellucida, consists of two types of cells (__ and __)

outer epithelial layer

small inner group of cells

each blastomere at the ___ and the ___ stage contributes cells to both the inner cell mass and the trophoblast

the end of the blastocyst that contains the inner cell mass is known as the ___, and the opposite end is called the ___

cells of the __ give rise to the body of the embryo itself in addition to several extraembryonic structures, whereas cells of the ___ form only extraembryonic structures, including the outer layers of the ___

there is increasing evidence that ____ acts to maintain mitotic activity in the overlying trophoblast

(a growth factor secreted by cells of the inner cell mass),