Reference Terms
from Wikipedia, the free encyclopedia
Placenta
The placenta is an ephemeral (temporary) organ present only in female placental vertebrates during gestation (pregnancy). All mammals other than monotremes and (most) marsupials utilise placentas in reproduction, and are known as placental mammals. Also, some species of snakes utilise placentas.
The placenta is composed of two parts, one of which is genetically and biologically part of the fetus, the other part of the mother. It is implanted in the wall of the uterus, where it receives nutrients and oxygen from the mother's blood and passes out waste. This interface forms a barrier, the placental barrier, which filters out some substances which could harm the fetus. However, many other substances are not filtered out, including alcohol and some chemicals associated with smoking cigarettes. Several types of viruses, such as Human Cytomegalovirus, may also cross this barrier; this often leads to various degrees of birth defects in the infant. The placenta is connected to the fetus via the umbilical cord, which is composed of blood vessels and connective tissue. When the fetus is delivered, the placenta is delivered afterwards (and for this reason is often called the afterbirth).
Related Stories
1
2
Health & Medicine News
April 26, 2026
Apr. 26, 2026 Fish oil has long been praised as brain-boosting, but new research suggests the story may be more complicated. Scientists found that in people with repeated mild head injuries, a key omega-3 fatty acid in fish oil—EPA—may actually interfere with ...
Apr. 26, 2026 Scientists have uncovered how graphene oxide pulls off a remarkable trick: it hunts down and destroys harmful bacteria while leaving human cells completely unharmed. By targeting a molecule found only in bacterial membranes, this ultra-thin ...
Apr. 25, 2026 A gut bacterium may be quietly fueling depression through an unexpected chemical twist. Researchers found that when Morganella morganii interacts with a common pollutant, it produces a molecule that ...
Apr. 23, 2026 A newly confirmed mass grave in ancient Jordan offers chilling insight into one of history’s first pandemics. Hundreds of plague victims were buried within days, revealing how the Plague of Justinian devastated entire communities. The findings ...
Apr. 23, 2026 A rare group of adults over 80, known as SuperAgers, are rewriting what we thought was possible for the aging brain. With memory abilities comparable to people decades younger, their brains either resist or withstand the damage typically linked to ...
Apr. 23, 2026 Scientists have identified two specific types of brain cells that behave differently in people with depression, offering a clearer picture of what is happening inside the brain. By analyzing donated brain tissue with advanced genetic tools, the ...
Apr. 23, 2026 A new minimally invasive procedure may help people keep weight off after stopping popular drugs like Ozempic and semaglutide—something most patients struggle with. In a clinical trial, those who underwent a technique called duodenal mucosal ...
Apr. 22, 2026 A new virus-fighting plastic film could transform everyday surfaces into invisible defenders against disease. Instead of relying on chemicals, this flexible material is covered in microscopic pillars that physically stretch viruses until they burst, ...
Apr. 22, 2026 Scientists at UC Irvine have found a way to potentially reverse age-related vision loss by targeting the ELOVL2 “aging gene” and restoring vital fatty acids in the retina. Their experiments in mice show that supplementing with specific ...
Apr. 22, 2026 A newly discovered virus hiding inside a common gut bacterium could help explain one of medicine’s long-standing mysteries: why a microbe found in both healthy people and cancer patients is linked to colorectal cancer. The research suggests that ...
Apr. 22, 2026 A routine blood marker tied to inflammation may reveal Alzheimer’s risk years in advance. Scientists found that higher neutrophil levels—part of the body’s first immune response—were linked to a greater chance of developing dementia. The ...
Apr. 22, 2026 Scientists have discovered that combining two existing drugs can dramatically reduce liver fat linked to a common and often silent disease. The treatment not only improved liver health in animal models but also showed potential to lower ...
Latest Headlines
updated 12:56 pm ET
Apr. 21, 2026 A key protein, HOXD13, helps melanoma tumors grow and evade the immune system by boosting blood supply and blocking cancer-fighting T cells. ...
Apr. 21, 2026 A popular Korean skincare ingredient may be far more powerful than anyone realized. Scientists have discovered that madecassic acid—derived from the herb Centella asiatica—can stop ...
Apr. 20, 2026 Cancer cells are known for their “glutamine addiction,” but many can escape this weakness by switching to alternative fuels. Researchers found that vitamin B7 acts like a metabolic “license,” ...
Apr. 20, 2026 A trio of common amino acids may hold the key to unlocking far more powerful gene therapies. Researchers found that adding them to lipid nanoparticles can boost mRNA delivery up to 20-fold and push ...
Apr. 18, 2026 Extra virgin olive oil might help protect your brain by working through your gut. A two-year study found that people who consumed it had better cognitive performance and more diverse gut bacteria ...
Apr. 18, 2026 Sitting all day might not be as damaging as once feared—if you’re willing to move more. A massive study tracking over 72,000 people found that ...
Apr. 18, 2026 Engineers at Northwestern University have taken a striking leap toward merging machines with the human brain by printing artificial neurons that can actually communicate with real ones. These ...
Apr. 17, 2026 A surprising new study suggests that eating a very healthy diet—packed with fruits, vegetables, and whole grains—might be linked to a higher risk of lung cancer in younger non-smokers. ...
Apr. 17, 2026 Scientists have uncovered a surprising twist in how bacteria share genes—including those that spread antibiotic resistance. Tiny virus-like ...
Apr. 17, 2026 Sparkling water is often seen as a simple, healthy drink—but could it also help with weight loss? New research suggests it may slightly boost how the body processes blood sugar and energy. However, ...