This is what happens inside your body when you're sick

A quick video on how your immune system works

Explore how your immune system’s vast network of cells, tissues, and organs coordinate your body’s defenses against bacteria, viruses and toxins with this 5-minute TED talk video.

The inner life of a cell

White blood cells are responsible for protecting the human body from infection. This video uses biophysical data from Harvard researchers to accurately demonstrate what goes on inside one white blood cell as it works within the immune system.

See why food poisoning makes you feel nauseous

Scroll through these illustrations to learn what’s happening behind the scenes with bacterial foodborne illnesses, including why we sometimes vomit and how the body reacts to toxins secreted by bacteria.

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

The gut microbiome, explained

This video from 1440 takes a high-level look at what populates the gut microbiome, its purpose, how it affects our health, and much more.

Fungi make people sick when they invade and survive in otherwise healthy human tissue

We breathe in airborne spores frequently, but they often don't make us sick. This video details how certain concerning fungal changes can occur and discusses the role of mycologists—scientists who study fungi—in helping to improve human health.

Watch what depression does to the brain

This video explores the neurobiology of depression and why unraveling the complexities of this disease and its etiology will potentially improve treatments. Effective depression treatment, as this video highlights, can eventually make a depressed brain look like a healthy one on brain scans.

Watch what the Ebola virus does inside the body in order to spread and survive

Once infected, the virus targets the body's immune cells, spreading the infection throughout the body. Patients exhibit severe flu-like symptoms. Ebola then targets the liver, which produces proteins that help blood clot, and the adrenal glands, which control blood pressure. The immune system may overreact to the viral invasion, releasing a cytokine storm that can result in shock, multiple organ failure, and death.

Aging is a complex biological process affecting our cells, tissues, and organs

With each passing decade, researchers uncover additional causes and effects of this seemingly unstoppable process. This visually stimulating video dives into our current understanding of aging, complete with the biological hallmarks researchers use to study aging at the cellular level (biological age).

See how cholera spreads in a community

This animated video offers a comprehensive look at how cholera spreads. It makes clear why it's so difficult to stamp out this disease in communities around the world. It also details what steps can help control cholera.

The biology of stress in your body

Stress is a normal human response that has evolved over millions of years to handle changes or threats in our environment. This article is a helpful overview of the biological basics of this response. While it is not harmful to our physiology in the acute setting, chronic stress can lead to damaging changes in the human body over many years.

Take a 360-degree look at biochemical activity from within a human cell

In this tour, users can observe the dynamic processes that occur within the basic units of the human body, including the production and transport of proteins and the assembly and disassembly of microtubules—thin, cylindrical structures that provide structural support and a means of moving material within the cell.

The basics behind mRNA vaccines

In this video, Yale experts Saad Omer, MBBS, MPH, PhD; Onyema Ogbuagu, MBBCh; and Akiko Iwasaki, PhD, explain the science behind COVID-19 mRNA vaccines.

We hear because soundwaves are converted into electrochemical signals in our ears

This science teacher video systematically walks through the biology of the outer, middle, and inner ear. The explanation starts with the auricle, an external part that funnels sound through the auditory canal, and the tympanic membrane (the ear drum), which vibrates when sounds hit it. Beyond that, as the video details, is the eustachian tube, which is connected to the back of our throats and allows air to pass in and out to equalize ear pressure.

How the body produces urine

Things seem so simple when nature calls. But, how does the body actually produce the urine we so regularly and thoughtlessly expel? This detailed, comprehensive animation walks viewers through every step with precise illustrations, from the kidney's filters (known as nephrons) to the direct nerve connecting the bladder to the brain. See how the body does it here.

On average, people smell worse if they're sick

For a small 2014 research study, a panel was tasked with sniffing the smelly t-shirts of people who had been injected with a compound known to activate the immune system and those of controls without the shot. It found that those who were acting as if unwell (due to the injection) generally smelled worse. Subsequent work found that those who sniffed unpleasant odors had a mild immune response of their own—perhaps to protect them from disease. (Some users may experience a paywall.)

Real surgical footage reveals what arthritis looks like up close

Arthritis is a painful condition of human joints that often results from the loss or breakdown of the soft cartilage padding that naturally exists between bones. This video shows footage from an actual knee surgery that beautifully demonstrates the difference between normal cartilage and the degenerative cartilage seen in osteoarthritis.

Goose bumps require a surprisingly complex series of steps

Watch an anatomical breakdown of how goose bumps work—featuring real skin from a human cadaver, a segmented brain, and a detailed anatomical model of the skin—to learn about all the jargon behind goose bump science. (Warning: Includes graphic footage of cadaver skin.)

See this first-person virtual reality view of vertigo

This video shows a virtual reality environment view of what benign paroxysmal positional vertigo will look like, from a first-person view. It includes a virtual rendering of eye spinning associated with the condition. (Warning: Watching this may make some users feel a bit nauseous.)

The human body relaxes upon death, including the bowel and bladder, expelling urine and feces

Watch a hospice nurse walk through how death affects the human body and what to expect in the hours and days following the death of a loved one as the body breaks down.

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

Hear firsthand stories from Americans who lived through the 1918 flu pandemic

This video shares personal accounts from survivors of the 1918 influenza epidemic, capturing memories of sickness, loss, and resilience. Their voices offer a glimpse into how ordinary people experienced one of history’s deadliest pandemics.

What it's like to live with insomnia

The biological process Shakespeare referred to as the chief nourisher of life's feast is necessary for the body and mind to rest and repair from the activities of daily life. As sleep evades the exhausted, sufferers also lose emotional stability, mental clarity, social connections, and more while simultaneously gaining waves of interrupted biological processes that can lead to disease and death.

If you have a cold, the body produces excess mucus to trap germs

This process clogs up narrowed nasal airways, which results in congestion. This process is often accompanied or triggered by swelling of blood vessels in the nose.

Attenuated vaccines introduce a weakened version of the virus into the body

Some vaccines, like those for measles, rely on weakened versions of a virus. These weakened pathogens are introduced into the body, triggering an immune response and helping the immune system learn to protect itself against stronger versions of the virus. (This also explains why some vaccines make you feel under the weather.)

Learn about the more than 100 known autoimmune diseases

Explore this resource with summaries and related resources for the dozens of autoimmune diseases defined in the medical literature. Many of these disease write-ups also have interviews with a patient with the disorder—offering a personal take about challenges, advice, and lifestyle effects.

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

Bank runs, explained

A major feature of the modern financial system is trust: if an institution loses it, customers will quickly withdraw deposits and stockholders will sell their shares. This digestible animated video looks into the nature and history of bank runs and...

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.

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

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

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

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

This real-time tracking of the hantavirus cruise ship outbreak in May 2026 offers a unique glimpse into the global reach of the outbreak and whether the virus sickened passengers and their communities around the world.

This poison ivy knowledge quiz—accompanied by photos of the plant's varied forms—may help you identify this common rash-inducing growth.

Explore the animals that populate the depths of the ocean, from fish and coral in the first few hundred feet, all the way down to the bottom of the Mariana Trench.

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

Larger animals like giraffes, elephants, and blue whales have developed a unique defense against cancer, a phenomenon known as Peto's Paradox

The syncytiotrophoblast is the outer layer of the placenta and the largest human cell, spanning an area about twice that of a king-sized bedsheet.

This site reaches millions of visitors who are tired of AI chatbots and seeking human connection. Pretend to be an AI chatbot and ask questions, provide answers, and draw for people in real time.

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.

Discover the catastrophic consequences of a failure of the US electrical grid—something that is more likely than many Americans think.

In 1939, baseball star Lou Gehrig delivered his inspirational 'Luckiest Man' speech after retiring due to the health condition that now bears his name.

Take a 3D tour of the Hajj, Islam's annual pilgrimage to Mecca, undertaken by more than 1.5 million Muslims each year.

Watch this video that uses Lego bricks to explain how venture capital works.

Netflix profits when you're not watching, and its movies are designed that way—read a detail-rich critical essay exposing lesser-known Netflix takes

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.

Some researchers have labeled nomophobia, the fear of being without your phone, as 'the phobia of the 21st century.'

Salvador Dalí believed he was his own dead brother, who had died nine months before he was born

In 2019, a laptop loaded with six of the worst malware in history and described as 'an exhibit of historical weaponry' sold for $1.3M.