The whitefish slide is from a blastula, an early stage in embryonic development. why do you think that this sample was chosen rather than a sample of adult tissue? hint: recall the discussion about how many times a cell must divide to create all of the cells in an adult human.

In the morula phase, the zygote begins to divide by mitosis, which is from one cell to two cells, two cells to four cells, four cells to 8 cells, and so on.

This cell division occurs continuously during the zygote journey to the uterus (approximately 4 days). This division produces daughter cells that are collected in a colony like a round ball, hereinafter called morula. In its growth, the morula will become a blastula that has cavities. This process of forming a morula is called morulation.

The blastula phase is a continuation of the formation of the morula which is continuously dividing. The shape of the blastula begins with irregularly curved cell changes. This blastula formation process is called blastulation. Inside the blastula, there is a cell fluid called the blastocoel. In the blastula wall, there is a sticky part that will help the process of attaching the zygote to the endometrium (uterine wall) or called the implanting process. Furthermore, the blastula will undergo a process of gastrulation or the process of cavity formation (gastrus).

Single-cell (which has been fertilized)

After initial fertilization, a diploid zygote nucleus is formed. Next will undergo mitotic division and begin the next stage of embryogenesis which is the formation of morula, blastula, gastrula, neurula, and ends in organogenesis)

Morula

After the initial cell division (cleavage), the cells in the embryo will divide miosis quickly into many small cells called blastomeres.

Blastula

Morula will experience a division that continues to form a cavity in the middle. This cavity is getting bigger and bigger with liquid. An embryo that has this cavity is called a blastula. This is called the blastocele.

Gastrula

Gastrula comes from the word gastric (stomach) because at this stage it will form a cavity that will become the digestive tract. The gastrula cavity is called a gastrosel (archenteron). After reaching the form of the blastula, cell mass increase still continues with the mitotic division.

Neurula

After the gastrula is formed, the embryo will differentiate, namely the change of cells that have not been specialized into cells that have a special structure and function. This means changes in physical properties and function of cells as cells multiply from the embryo to form different body structures.

Organogenesis

After neurulation, the embryo begins to reorganize to form a more perfect embryo through several stages, namely:

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Embryogenesis

several phases

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Class: College

Subject: Biology

Keyword: embryo, phases, cells

a compound light microscope is used to magnify objects in steps.  

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