New! Sign up for our free email newsletter.
Reference Terms
from Wikipedia, the free encyclopedia

Mammalian embryogenesis

Mammalian embryogenesis is the process of cell division and cellular differentiation which leads to the development of a mammalian embryo. A mammal develops from a single cell called a zygote, which results from an ovum (egg) being fertilized by a single sperm. The zygote is surrounded by a strong membrane of glycoproteins called the zona pellucida which the successful sperm has managed to penetrate.

The zygote undergoes cleavage, increasing the number of cells within the zona pellucida. After the 8-cell stage, mammalian embryos undergo what is called compactation, where the cells bind tightly to each other, forming a compact sphere. After compactation, the embryo is in the morula stage (16 cells). Cavitation ocurrs next, where the outermost layer of cells - the trophoblast - secrete water into the morula. As a consequence of this when the number of cells reaches 40 to 150, a central, fluid-filled cavity (blastocoel) has been formed. The zona pellucida begins to degenerate, allowing the embryo to increase its volume. This stage in the developing embryo, reached after four to six days, is the blastocyst (akin to the blastula stage), and lasts approximately until the implantation in the uterus. The blastocyst is characterized by a group of cells, called the inner cell mass (also called embryoblast) and the trophoblast (the outer cells).

Related Stories
 


Plants & Animals News

July 29, 2025

Eggs are finally being vindicated after decades of cholesterol-related blame. New research from the University of South Australia reveals that eggs, despite their cholesterol content, aren't the dietary villains they've long been made out to be. ...
Mesopelagic fish, long overlooked in ocean chemistry, are now proven to excrete carbonate minerals much like their shallow-water counterparts—despite living in dark, high-pressure depths. Using the deep-dwelling blackbelly rosefish, researchers ...
A groundbreaking study has revealed that the mass administration of ivermectin—a drug once known for treating river blindness and scabies—can significantly reduce malaria transmission when used in conjunction with bed ...
Fermenting stevia with a banana leaf-derived probiotic turns it into a powerful cancer-fighting agent that kills pancreatic cancer cells while sparing healthy ones. The secret lies in a metabolite called CAME, produced through microbial ...
Millipedes, often dismissed as creepy crawlies, may hold the secret to future painkillers and neurological drugs. Researchers at Virginia Tech discovered unique alkaloid compounds in the defensive secretions of a native millipede species. These ...
Scientists have discovered a sugar compound from deep-sea bacteria that can destroy cancer cells in a dramatic way. This natural substance, produced by microbes living in the ocean, causes cancer cells to undergo a fiery form of cell death, ...
New research from the University of Sydney sheds light on how coronaviruses emerge in bat populations, focusing on young bats as hotspots for infections and co-infections that may drive viral ...
What scientists once dismissed as junk DNA may actually be some of the most powerful code in our genome. A new international study reveals that ancient viral DNA buried in our genes plays an active role in controlling how other genes are turned on ...
A scorching marine heatwave from 2014 to 2016 devastated the Pacific coast, shaking ecosystems from plankton to whales and triggering mass die-offs, migrations, and fishery collapses. Researchers ...
Gene editing may hold the key to rescuing endangered species—not just by preserving them, but by restoring their lost genetic diversity using DNA from museum specimens and related species. Scientists propose a visionary framework that merges ...
Romaine lettuce has a long history of E. coli outbreaks, but scientists are zeroing in on why. A new study reveals that the way lettuce is irrigated—and how it’s kept cool afterward—can make all the difference. Spraying leaves with untreated ...
Dogs trained by everyday pet owners are proving to be surprisingly powerful allies in the fight against the invasive spotted lanternfly. In a groundbreaking study, citizen scientists taught their ...

Latest Headlines

updated 12:56 pm ET