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
October 27, 2025
Oct. 27, 2025 — King’s College London researchers discovered that parts of our DNA once thought to be “junk” can actually help destroy cancer cells. In some blood cancers, damaged genes trigger chaos in these DNA segments, leaving cancer cells vulnerable. ...
Oct. 27, 2025 — People with both cavities and gum disease were found to have an 86% higher stroke risk than those with healthy mouths. The study followed thousands of adults for two decades, linking poor oral health with major cardiovascular events. Regular dental ...
Oct. 27, 2025 — A team of researchers has developed a floral-scented fungus that tricks mosquitoes into approaching and dying. The fungus emits longifolene, a natural scent that irresistibly draws them in. It’s harmless to humans, inexpensive to produce, and ...
Oct. 26, 2025 — Researchers found that life expectancy growth in wealthy nations has dramatically slowed since 1939. Once driven by major reductions in child mortality, longevity gains are now limited by slower progress in older-age survival. The study suggests no ...
Oct. 26, 2025 — GLP-1 drugs, originally developed for diabetes and obesity, may also curb addictive behaviors by acting on reward circuits in the brain. Early trials show reductions in alcohol intake, opioid seeking, and nicotine use. Though more research is ...
Oct. 26, 2025 — Researchers have uncovered microbial evidence in the remains of Napoleon’s soldiers from the 1812 Russian retreat. Genetic analysis revealed pathogens behind paratyphoid and relapsing fever, diseases likely contributing to the army’s massive ...
Oct. 26, 2025 — Researchers found that combining regular exercise with omega-3 supplements can make a big difference for oral health. The duo helps the immune system fight off chronic tooth root infections and reduces bone loss around the teeth. In animal studies, ...
Oct. 25, 2025 — A new study shows that eating more fruits and vegetables during the day can significantly improve sleep that same night. Researchers found a clear link between diet quality and sleep depth, with participants who met the CDC’s daily produce ...
Oct. 25, 2025 — Researchers found that neurons can use fat, not just sugar, to power the brain. When a protein called DDHD2 fails, this process breaks down and leads to serious brain problems. Scientists were able to restore damaged cells by feeding them fatty ...
Oct. 25, 2025 — Inside your body, an intricate communication network constantly monitors breathing, heart rate, digestion, and immune function — a hidden “sixth sense” called interoception. Now, Nobel laureate ...
Oct. 25, 2025 — Scientists at The University of Texas at Austin have developed a revolutionary gene-editing method using bacterial retrons that can correct multiple disease-causing mutations at once. Unlike traditional tools limited to one or two mutations, this ...
Oct. 25, 2025 — Reptiles don’t just pee, they crystallize their waste. Researchers found that snakes and other reptiles form tiny uric acid spheres, a water-saving evolutionary trick. This discovery could illuminate how to prevent gout and kidney stones in ...
Latest Headlines
updated 12:56 pm ET
Oct. 25, 2025 — Japanese researchers discovered that hair graying and melanoma share a surprising cellular origin. When DNA damage strikes melanocyte stem cells, they may undergo a protective process called ...
Oct. 25, 2025 — Scientists have identified mutations in the CPD gene as a key cause of a rare congenital hearing loss, revealing how disruptions in arginine and ...
Oct. 24, 2025 — Researchers uncovered how lung cells decide whether to rebuild tissue or fight infection. This built-in “switch” may be the key to restoring the lungs’ natural repair ability. The discovery ...
Oct. 24, 2025 — ASU scientists found that people whose gut microbes make more methane extract more calories from fiber-rich foods. Methanogens help the microbiome turn fiber into energy by consuming hydrogen and ...
Oct. 24, 2025 — A massive genetic study found that naturally lower cholesterol is linked to a dramatically reduced risk of dementia. The research simulated the effects of cholesterol-lowering drugs and showed up to ...
Oct. 24, 2025 — Researchers have finally seen and measured the tiny alpha-synuclein oligomers that may ignite Parkinson’s disease. With the ultra-sensitive ASA-PD imaging method, they captured these clusters in ...
Oct. 23, 2025 — Colorado researchers discovered that nearly half of tested cannabis flower products exaggerated their THC levels, while concentrates were mostly accurate. The team’s statewide audit revealed ...
Oct. 23, 2025 — Cedars-Sinai researchers created “young” immune cells from human stem cells that reversed cognitive decline and Alzheimer’s symptoms in mice. The treated animals showed better memory and ...
Oct. 23, 2025 — McMaster researchers found that deep abdominal and liver fat can quietly damage arteries, even in people who appear fit. Their MRI-based study of ...
Oct. 23, 2025 — MIT scientists have found that an amino acid called cysteine can help the gut heal itself. In mouse studies, a cysteine-rich diet activated immune cells that release a molecule speeding up tissue ...