Taste buds are found throughout the body, with different biological functions

Taste buds have evolved to fill a wide variety of functions

Taste buds do more than let you experience your favorite food. These peripheral organs can sense the chemical makeup, potential toxicity, and fleeting experience of flavor, giving the body a chance to respond to undesirable chemicals or tell the brain that you should reach for another scoop.

Many parts of the body, including the testicles, have bitter, sweet, and umami receptors

Taste receptors—the tiny cells that report the chemical makeup of external stimuli to the brain—in the testicles don't "taste" in the same way as the gustatory ones you use to determine if there's enough sugar in your tea. Research suggests that these "teste" receptors can sense bitter, sweet, and umami compounds and use that chemical input to control physiological processes or (literally) change direction. (Some users may experience a paywall.)

These cells 'taste' danger, trigger immune responses

Taste receptor-coated tuft cells are found throughout the body, where they communicate with and take part in a growing list of biological processes. In the intestines, these taste receptor-studded cells can sense byproducts of parasite metabolisms. This causes the taste receptors to release chemicals that alert the immune system, order nearby goblet cells to produce mucus, and trigger muscle contractions in attempts to launch the parasites from the intestines.

Each taste bud has 10 to 50 sensory cells that form a flower-like capsule

At the top of the structure are thin filaments known as "taste hairs" that bind taste-producing substances to the surfaces of the cell, after which corresponding electrical signals are sent to the brain. Adults have 2,000 to 4,000 taste buds on their tongue.

How bitter taste receptors help guard against infection

Receptors for "bitter" tastes evolved to detect potentially harmful plant chemicals, such as nicotine. The receptors also trigger bacteria-fighting responses, including waving hairlike projections to bat away bacteria, ordering the release of bacteria-killing nitric oxide, and calling for antimicrobial protein reinforcements.

The research that led to sour

Scientists are trying to figure out if there are unique receptors that respond to the molecules that make up flavors we associate with calcium, blood, batteries, and other items that often escape dinner menus. Taste researcher Dr. Danielle Reed says the minimum evidence for a taste category typically involves identifying dedicated receptors and then removing them to show the taste vanishes.

Our sense of smell affects what foods taste like and how we perceive it

Scent stimulates our olfactory sensor neurons high in the nasal cavity, and the brain attaches labels to those scents. But when we eat, chemicals from the foods travel from our mouths and throat to those neurons. We have roughly 400 odor receptors, and they can be used to decipher more than 10,000 different odors (or more than one trillion by some calculations), including the nuances of different foods.

Octopuses have taste receptors along their tentacles

Octopus suction cups are filled with modified sensory receptors that can bind with a greater variety of materials and transport a wider array of information, such as flavor, from tactile stimuli. These structures allow the animal to search for food as it crawls the ocean floor.

How the five senses share information with each other

The human body depends on information from the five sensory organs—the eyes, ears, nose, tongue, and skin—to react to the world around it. Each of these organs, in its own way, relies on complex circuitry to send signals back to the central nervous system.

The idea of a tongue map has been discredited (but taste sensitivity varies across the tongue)

The original tongue map, created by German researcher DP Hanig, recorded taste sensitivities reported in psychological studies. His findings were later translated and taken out of context, possibly giving rise to the faulty tongue map. In fact, taste receptors in the oral cavity respond to all tastes regardless of their location.

We can sense touch even through a tool

Research published in 2019 indicates that the same brain regions involved in sensing touch on the body also process it when humans use a tool to do the touching. Essentially, it's acting as a sensory extension of the body. (Some users may experience a paywall.)

Receptors on the cell surface are key to whether a virus is successful

Viral receptors are key regulators of host range, tissue tropism, and viral pathogenesis—basically, the door locks on cells allowing viruses to invade, if they have the right key. How this process works at the microscopic level determines whether a virus is able to trigger a widespread illness in the host.

Explore an interactive 3D model of the brain

The brain contains about 86 billion neurons—nervous system cells—and controls vital bodily functions via electrochemical signals. Neurons form circuits through axons, and different brain regions use these circuits to perform specific tasks.

Biosignatures are the chemical fingerprints astrobiologists search for to find life

The 21st century has introduced advances making telescopes, cameras, and computers powerful enough to detect the presence of molecules associated with biological processes in distant atmospheres, expanding the search for life to include unreachable worlds.

Nasal hairs, called vibrissae, help protect the body from particulate matter and other dirt

The nose structure plays a key role in filtering air before it enters our lungs and makes sure that the air temperature and humidity are also suitable for the body.

Explore how cells respond to signals from their environment

In "Dropping Signals," users can drag stimuli, such as hormones and light, into various cellular environments to observe cellular responses. These include changing their shape, enabling the transport of chemicals into or out of the cell via the cell membrane, or dividing to compensate for surrounding damaged cells.

How the body produces its own opioids

Opioids act on the body's own opioid receptor system. The endogenous opioid system comprises four molecule receptor types found throughout the body. When activated, these receptor types trigger the release of dopamine and suppression of noradrenaline, neurotransmitters, respectively, associated with reward and alertness. This opioid system helps regulate emotions, and its disruption is linked to neuropsychiatric conditions, including depression, PTSD, and Alzheimer's disease.

See where and how many microplastics are in the average human body

This diagram maps the extent to which microplastics have been found across human organ systems, tissues, and fluids. Beyond the locations shown, microplastics have also been found in the stomach, brain, and sex organs.

Snake venoms are repurposed proteins responsible for other bodily functions

Just as saliva aids digestion in humans, proteins responsible for bioactivities such as digestion and blood clotting were eventually secreted in the glands and fangs of snakes across evolutionary history. Organisms that could not withstand the effects of these molecules (e.g., excessive bloodstream clotting) became ideal prey for snakes.

The pancreas releases digestive enzymes and regulates blood sugar

The pancreas weighs about the same as a deck of cards and is smaller than the average adult human hand. This lopsided glandular organ controls blood sugar levels through insulin production and helps the body digest food by creating a neutralizing tonic filled with digestive enzymes.

Fruit fly experiments helped identify genes responsible for major body development

The insects' fast life cycle and affordability have allowed geneticists to quickly identify which genes are responsible for limbs, eyes, and other body structures by inducing mutations. The same genes may be responsible for different parts of a species' body, such as limb-building genes being responsible for wing pigmentation in butterflies.

A technical review of what researchers know about the gut microbiome

This overview from the National Institutes of Health provides a deeper (but still accessible) look at the different bacteria in the gut, how the microbiome develops through life, its purpose, and more.

Some organelles are believed to have once been independent cells

Mitochondria and chloroplasts, which are both responsible for energy production in cells, have DNA distinct from that of their host cells and are surrounded by cellular membranes resembling those of bacteria. Through symbiogenesis, these and other specialized structures were absorbed into larger cells, forming the modern-day biological units.

What does blood do?

Blood's primary purpose is to ferry oxygen and nutrients to cells in need while collecting cell waste and byproducts for removal. It also enables the body's repair and immune systems to traverse our internal landscape to address cell damage or external invaders, such as viruses and parasites. Zooming out from the exact roles of blood's various cells, the fluid connective tissue also assists with maintaining homeostasis via temperature regulation and pH balance.

Vitamins are micronutrients human bodies need but don't naturally produce

Each vitamin is found in specific portions of a normal human diet and supports normal human functioning in distinct ways. Vitamin A is found in red meat, carrots, and potatoes and supports vision and skin health, while Vitamin D (common in fish and mushrooms) helps absorb calcium. See sources and uses of each vitamin with this chart.

Tattoos remain visible on your skin thanks to immune cells called macrophages

Visualize how CRISPR-Cas9—a type of immune system used by single-celled organisms to attack invasive viruses—targets and makes precise changes to a gene's DNA.

Learn how your body is, scientifically, like a firework with its own slow, controlled burn.

Read a deep dive on the 'all-purpose healing' peptide BPC-157.

At the beginning of the 20th century, a group of young men ate standard American food—replete with food additives like borax and formaldehyde—as part of government research to better understand food safety.

After 25 people used virtual reality headsets to practice flying with virtual wings—flapping their arms—their visual cortex responded to the wings almost as if they were real arms, treating them as body parts.

Bone marrow (soft tissue found inside certain bones) generates roughly 500 billion new blood cells each day

Fear or disgust related to clusters of holes and cracks, called trypophobia, may stem from evolutionary processes to help us avoid pathogens.

Watch what the Ebola virus does inside our cells and organs in order to spread and survive.

Studies suggest when you sleep is as important as how much you get, and syncing with your circadian rhythms may lead to less fatigue and improved long-term health outcomes

Explore an interactive map built from more than 100,000 survey responses on where people find joy in their lives

Hookworm infection, though risky, may help fight certain autoimmune conditions by tamping down the immune system's inflammatory response.

Crows are believed to have intelligence on par with a seven-year-old child and demonstrate complex behaviors, from problem-solving with tools to recognizing human faces.

As of 2025, the most cited papers in science include a review of graphene, methods to improve image recognition, streamlining electron density calculations, and optimizing protein studies.

Alzheimer's can lead to brain shrinkage, with an average of around 2% of volume reduction per year

Poison ivy is in the same family as mangoes, cashews, and pistachios—and they all produce oily urushiol in their raw, unprocessed state—but they are typically prepared in ways to avoid causing human discomfort.

Some Pokémon have been named after real and fictional organisms, while some real-world species have been named after Pokémon, such as Chilicola charizard and Binburrum zapdos.

According to the physics of black holes, our 4D reality may be a hologram—a projection of information coded on a 2D surface on the edge of the universe.

The Great Salt Lake's distinct dual coloration results from high-salinity organisms that only live in the northern portion and produce a purple protein.

Browse a detailed visual analysis of over 200,000 similes—comparisons that often use 'like' or 'as'—from popular fiction to see how frequently writers the same idiomatic expressions.

Explore the history, structure, and species of Australia's Great Barrier Reef with this interactive journey narrated by Sir David Attenborough.

See how Budweiser's famous Clydesdales spend their days at Warm Springs Ranch, where roughly 70 to 80 of the beer brand's giant horses can be found at any given time.

The Brothers Grimm were lawyers before they were storytellers, but became interested in fairy tales as they began investigating how rules and customs had been passed down through cultures.

Scientists can determine Earth's past climate conditions by analyzing air trapped in microscopic bubbles within ice cores—columns of compressed snow layers that build up over hundreds of thousands of years.

The United States is one of only around two dozen countries with a fully federal system of government, in which power is divided between national and state governments.