Interactive Biology Visualizations
Hard-to-picture biology, brought to life. Each page is a hands-on, animated diagram built in JavaScript — press play, slow it down, trigger the process yourself, and watch how a part of the human body actually works, with live readouts in real units. Made for students, patients, and the curious.
One hundred twenty-nine systems — pick one below and everything moves.
Mitochondria & ATP
Watch electrons flow through the electron transport chain, protons get pumped, and the ATP-synthase motor spin as your cells make energy — then block Complex IV with cyanide and see the whole chain stall.
Launch animation →DNA → Protein
Unzip DNA in the nucleus, transcribe it into mRNA, then step codon by codon as the ribosome matches tRNA anticodons and links amino acids into a protein.
Launch animation →The Methylation Cycle
Hand a methyl group from folate to B12 to homocysteine and back — then knock out B12 and watch the folate trap slam shut while homocysteine climbs.
Launch animation →The Sodium–Potassium Pump
Run the pump that gives every cell its voltage — three sodium out, two potassium in, on Mg-ATP. Then drop the magnesium and see exactly why low potassium refuses to correct.
Launch animation →Free Radicals & Your Antioxidant Network
Follow one superoxide radical down the whole relay — SOD, catalase, glutathione, vitamin E, vitamin C, NADPH. Then release free iron and watch the Fenton reaction tear a membrane apart.
Launch animation →From Sugar to Energy: Glycolysis & the Krebs Cycle
Split one glucose into two pyruvate through ten enzyme steps, feed them into the Krebs cycle, and load the NADH and FADH₂ carriers the mitochondria turn into ATP — then cut the oxygen and watch it fall back to lactate.
Launch animation →Lactate, the Cori Cycle & the Muscle-Burn Myth
Sprint until lactate floods your blood, then follow it to the liver to be rebuilt into glucose and sent back — and finally bury the myth that lactic acid causes the burn or next-day soreness.
Launch animation →The Cell Cycle & How Cancer Hijacks It
Turn the cell-division cycle through its four phases and its checkpoints — then damage the DNA and watch p53 halt it, or knock out the brakes and jam the accelerator and watch a tumour grow.
Launch animation →How Your DNA Is Repaired — and Why It Fails in Cancer
Send a repair crew down the DNA to snip out UV damage, fix copy errors, and mend double-strand breaks with BRCA — then switch the crew off and watch mutations lock in and cancer risk climb.
Launch animation →Apoptosis: Your Cells’ Programmed Self-Destruct
Watch a damaged cell trigger its own tidy self-destruct with caspases — then see cancer block the death switch so bad cells survive, or too much of it kill healthy neurons.
Launch animation →Telomeres: Why Cells Grow Old
Watch chromosome caps shorten with every cell division until the cell retires — the built-in anti-cancer clock — then see cancer switch telomerase back on to become immortal.
Launch animation →Autophagy: How Fasting Cleans Out Your Cells
Watch a cell wrap up its damaged parts, digest them in the lysosome and recycle the pieces — idle when you’re fed, ramping up when you fast, and failing when junk piles into disease.
Launch animation →How Proteins Fold — and Misfold in Disease
Watch a chaperone help a new protein fold into its working shape — then take it away and see it clump into the aggregates behind Alzheimer’s and Parkinson’s, or a prion convert its neighbours.
Launch animation →Getting In and Out of a Cell: Membrane Transport
See every way things cross a cell membrane — oxygen slipping through, water following salt, channels and carriers ferrying downhill, and pumps hauling uphill on ATP — the one framework behind nerves, kidneys and drugs.
Launch animation →Mitosis: How One Cell Becomes Two
Watch a single cell condense its chromosomes, line them up on the spindle, and split into two identical daughters — then force a mis-segregation and see how a cell ends up with an extra or missing chromosome.
Launch animation →Meiosis: Making Eggs & Sperm
Halve the chromosome count to build eggs and sperm, shuffle them with crossing-over and independent assortment for millions of combinations — then trigger nondisjunction and watch an aneuploid gamete form.
Launch animation →Enzymes: How They Speed Up Life
Drop a substrate into an enzyme's active site and watch induced-fit catalysis fly over the activation-energy hill — then heat it, swing the pH, or add a competitive inhibitor and watch the reaction stall.
Launch animation →Inheritance: Dominant, Recessive & Punnett Squares
Cross two parents and watch their alleles sort into a Punnett square — flip dominance and carrier status to see why two brown-eyed parents can still have a blue-eyed child.
Launch animation →How Genes Are Switched On & Off
Dock transcription factors on a promoter and watch RNA polymerase read the gene — then add a repressor, methylate the DNA, or send in a hormone and watch the same gene fall silent or roar back.
Launch animation →CRISPR: How Gene Editing Works
Program a guide RNA, watch Cas9 hunt down its 20-letter match and cut both DNA strands — then let the cell's repair machinery knock a gene out or paste a healthy one in.
Launch animation →How Cancer Spreads (Metastasis)
Follow one tumour cell as it loses its grip, invades a blood vessel, survives the bloodstream and seeds a distant organ — the exact cascade, checkpoint by checkpoint, that makes cancer deadly.
Launch animation →The Heart & Circulation
Trace a blood cell through all four chambers and both circuits, changing colour from blue to red in the lungs — with a live ECG, chamber pressures, and an exercise mode.
Launch animation →Blood Pressure Control
Watch the kidney fire renin, angiotensin clamp the arteries, and aldosterone hold on to sodium — then eat salt, get dehydrated, or take an ACE inhibitor.
Launch animation →Cholesterol & the Artery Wall
Follow LDL particles into the artery wall and watch foam cells build a plaque — then add a statin and see the liver's receptors pull them back out.
Launch animation →Nitric Oxide & Vessel Dilation
Watch the endothelium turn L-arginine into nitric oxide, relax the artery wall, and widen the lumen — then let oxidative stress uncouple eNOS and see the vessel stiffen, or pour in beet nitrate to rescue it.
Launch animation →Breathing & Gas Exchange
Move the diaphragm, fill the alveoli, and watch oxygen diffuse into the blood while carbon dioxide leaves — with live pO₂/pCO₂ meters and an exercise mode.
Launch animation →How Blood Clots
Cut the vessel and watch platelets plug it while the coagulation cascade explodes into a fibrin mesh — then take warfarin and see the vitamin-K factors go dark one by one.
Launch animation →Iron & the Hepcidin Gate
Watch vitamin C unlock plant iron and hepcidin slam the gate shut — then add inflammation and see why a high ferritin can still mean too little usable iron.
Launch animation →Potassium & the Heartbeat
Slide your blood potassium up and down and watch the ECG morph in real time — peaked T waves and a widening QRS as it climbs, U waves and a stretched QT as it falls — with an alarm at the danger lines and a beating heart that hears every one.
Launch animation →Blood pH: The Acid–Base Balancing Act
Hold your blood pH on a knife-edge between 7.35 and 7.45 — blow off CO₂ with the lungs in minutes, dump acid through the kidneys over hours, then break it with hyperventilation or diabetic ketoacidosis.
Launch animation →How Blood Clots Dissolve — Fibrinolysis & Clot-Busters
Once the vessel heals, watch plasmin snip the fibrin mesh strand by strand and D-dimer wash away — then add a tPA clot-buster to blast it, or tranexamic acid to hold it shut.
Launch animation →The Lymphatic System: Your Body’s Drainage & Surveillance
Watch the fluid your blood leaks get collected, squeezed along by moving muscles through one-way valves and filtering lymph nodes, and returned to the blood — then block a node and watch the limb swell.
Launch animation →Hemoglobin & the Oxygen Dissociation Curve
Load oxygen onto hemoglobin one cooperative step at a time to draw the famous S-curve — then shift it with exercise, watch carbon monoxide lock it shut, or switch to fetal hemoglobin pulling O₂ from mom.
Launch animation →Blood Types: ABO, Rh & Why Transfusions Must Match
Transfuse blood and watch a match flow safely while a mismatch clumps and bursts — then see why O-negative is the universal donor and how a RhoGAM shot protects a second Rh-positive baby.
Launch animation →The Baroreflex: Your Blood Pressure’s Split-Second Autopilot
Stand up and watch your blood pressure dip, then get caught in a heartbeat by the baroreceptors and brainstem — or trip a vasovagal faint and see why passing out actually rescues the brain.
Launch animation →How Your Body Makes Red Blood Cells (EPO)
Watch the kidney sense low oxygen and fire EPO at the bone marrow to build red cells — then climb a mountain to surge it, lose it in kidney disease, or dope with it and thicken the blood.
Launch animation →Surfactant: Why Your Lungs Don’t Collapse
See why 300 million wet air-sacs don’t collapse from surface tension — a soapy surfactant holds them open — then take it away, as in a premature baby, and watch the lungs stiffen and collapse.
Launch animation →Platelets: The First Responders to a Cut
Watch platelets stick, turn spiky, and pile into a plug seconds after a cut — then take aspirin and see the plug weaken, and finally sort out how antiplatelets differ from blood thinners.
Launch animation →The Heart’s Electrical System & the ECG
Follow the spark from the SA-node pacemaker across the atria, through the AV-node pause, and down the fast fibres to fire the ventricles — read it live on the ECG, then break it into heart block or fibrillation.
Launch animation →Your Airway’s Self-Cleaning Escalator (& the Cough)
Watch millions of cilia sweep a mucus blanket of trapped dust and germs up and out of your lungs — then trigger a cough to blast an irritant clear, or light a cigarette and watch the escalator freeze.
Launch animation →How a Pulse Oximeter Reads Your Oxygen
See how a finger clip reads your blood oxygen with two colours of light — measuring only the pulsing artery signal — and why it can read dangerously normal in carbon-monoxide poisoning.
Launch animation →How Heart Failure Develops
Weaken the pump and watch the ejection fraction fall, fluid back up into the lungs, and the body's own 'fixes' (RAAS, adrenaline) quietly make it worse — then unload it with the right drugs.
Launch animation →How Blood Gets Back to the Heart
Squeeze the calf-muscle pump and watch one-way valves march blood uphill against gravity — then let a valve fail and see blood pool backwards into a bulging varicose vein.
Launch animation →Blood Sugar & Insulin
Eat a meal and watch insulin escort glucose into cells, the liver bank glycogen, and the blood-glucose curve rise and fall — then switch on insulin resistance.
Launch animation →How Your Thyroid Is Controlled
Run the TSH feedback loop, convert T4 into T3, and set your metabolic rate — then switch on Hashimoto's, Graves', or iodine deficiency and watch the labs move.
Launch animation →The Stress Response & Cortisol
Fire a stressor: adrenaline spikes in a second, cortisol follows in minutes — then compare an acute stressor with chronic stress and watch the feedback loop blunt.
Launch animation →Sleep Stages & Your Body Clock
Run a whole night of deep sleep and REM — then add late-night light, an afternoon coffee, or a nightcap, and watch which parts of the night disappear.
Launch animation →Hunger, Leptin & Why Diets Fight Back
Watch the hunger neurons and the fullness neurons fight it out — then lose weight and see leptin fall, hunger climb, and metabolism drop. It isn't willpower. It's a defended system.
Launch animation →Fat Burning & Ketosis
Follow a fatty acid out of a fat cell to the mitochondrial gate — and find it padlocked by insulin. Drop the carbs, open CPT1, and watch the liver start making ketones.
Launch animation →GLP-1, Incretins & How the New Weight-Loss Drugs Work
Eat a meal and watch your gut fire GLP-1 at the pancreas, brain and stomach at once — then see how Ozempic-style drugs resist the enzyme that normally destroys it in two minutes.
Launch animation →Inside the Beta Cell: How Insulin Is Released
Zoom inside a single beta cell and watch glucose close the K-ATP channel, calcium flood in, and insulin granules pop out — then force the channel shut with a sulfonylurea, or hold it open with diazoxide.
Launch animation →How Insulin Opens the Cell: The GLUT4 Switch
Watch insulin dock a muscle cell and send GLUT4 doors to the surface so glucose pours in — then muffle the signal in insulin resistance, or open the doors with exercise, no insulin needed.
Launch animation →Brown Fat: How You Burn Calories as Heat
Watch brown-fat mitochondria leak their proton gradient through UCP1 to make pure heat instead of ATP — the uncoupling trick cold switches on, and the dangerous one a banned diet drug forced.
Launch animation →The Menstrual Cycle: Four Hormones in a Loop
Run the 28-day loop of FSH, LH, estrogen and progesterone — watch a follicle ripen, the LH surge burst the egg, and the lining build and shed — then see how the pill switches the whole loop off.
Launch animation →Growth Hormone: How You Grow (and Why It Stops)
Pulse growth hormone from the pituitary to the liver, make IGF-1, and lengthen bone at the growth plates — then hit puberty, fuse the plates, and see why too much GH means gigantism or acromegaly.
Launch animation →Your Daily Cortisol Rhythm
Ride the 24-hour cortisol curve from its midnight low to the morning peak that wakes you up — then work a night shift or read the test at the wrong hour and see why timing is everything.
Launch animation →Melatonin & the Body Clock
Let darkness raise melatonin and open the gate to sleep — then shine a screen at night to suppress it and delay your clock, fly across time zones for jet lag, or reset it with well-timed light.
Launch animation →How Breast Milk Is Made: Prolactin & the Let-Down Reflex
Watch a baby’s suckling release two hormones — prolactin to make the milk and oxytocin to squeeze it down in the let-down reflex — then add stress and see the adrenaline shut the let-down off.
Launch animation →Testosterone: The Male Hormone Axis
Follow the GnRH → LH → testosterone chain from brain to testes and watch negative feedback hold it steady — then see what puberty, ageing, and anabolic steroids do to the loop.
Launch animation →The Placenta: Feeding a Baby Before Birth
Watch oxygen, glucose and antibodies cross from mother to baby without their blood ever mixing — and see why the fetal side runs on a clever oxygen-grabbing haemoglobin.
Launch animation →Nerve Impulse
Fire an action potential and watch it race down the axon — sodium rushing in, potassium out, a live voltage trace spiking, and neurotransmitter crossing the synapse.
Launch animation →Dopamine, Reward & How Habits Hijack You
Dopamine is not the pleasure chemical. Watch the spike migrate from the reward to the cue, then withhold the reward and see it dip below zero — that dip is craving.
Launch animation →Caffeine, Adenosine & Why Coffee Stops Working
Caffeine doesn't give you energy — it blocks the tiredness signal while it keeps piling up behind the blockade. Move your coffee to 2 p.m. and watch your deep sleep disappear.
Launch animation →Serotonin, Mood & SSRIs
Build serotonin from tryptophan, fire it across the synapse, and vacuum it back with SERT — then take an SSRI and watch the cleft flood, or starve the tryptophan and watch the signal fade.
Launch animation →Vision & the Retina
Focus light through the lens onto an inverted retinal image, then follow the phototransduction cascade as rods and cones react — dim the lights and watch the eye adapt.
Launch animation →Hearing & the Cochlea
Send a sound wave through the eardrum and ossicles into the cochlea, and slide the frequency to see the traveling wave peak land on its tonotopic place — and now actually hear the pitch you set.
Launch animation →Pain, the Gate Control & Why Rubbing Helps
Fire a pain signal up the spinal cord — then rub the skin and watch the gate close, or release endorphins and see the same signal fade before it ever reaches the brain.
Launch animation →GABA: The Brain’s Brake
Watch glutamate try to fire a neuron while GABA slams the chloride brake on — then add a benzodiazepine or alcohol and see the brake amplified, and why stacking them is dangerous.
Launch animation →The Blood-Brain Barrier: The Brain’s Bouncer
Send molecules at the tightest wall in the body — watch fat-soluble ones slip through, big ones bounce, and a pump eject the rest — then see why L-DOPA gets in when dopamine can’t, and how meningitis breaks the gate.
Launch animation →The Reflex Arc: Faster Than Thought
Tap the tendon and watch the signal fire into the spinal cord and straight back out to the muscle in about 50 milliseconds — while the brain only finds out afterward. The knee-jerk isn’t your brain reacting fast.
Launch animation →Taste: The Five Basic Tastes & How Your Tongue Reads Them
Fire each of the five tastes and watch its own molecular trick — sweet, bitter and umami through G-protein receptors, salty and sour through ion channels — then discover that ‘spicy’ is pain, not taste, and the tongue map is a myth.
Launch animation →Smell: How Your Nose Reads a Trillion Odours
Send an odour at your ~400 receptor types and watch a unique pattern light up — how you smell a trillion things with a few hundred sensors, why smell hooks straight into memory, and why losing it warns of Parkinson’s.
Launch animation →Cerebrospinal Fluid: The Brain’s Cushion & Plumbing
Make CSF at the choroid plexus and follow it around the brain and spine and back to the blood — block the aqueduct to flood the ventricles (hydrocephalus), or fall asleep and watch the glymphatic system flush the brain’s waste.
Launch animation →The Neuromuscular Junction: How a Nerve Commands a Muscle
Fire a nerve and watch calcium dump acetylcholine across the gap to spark the muscle — then block it with Botox, strip the receptors in myasthenia gravis, or jam the off-switch with a nerve agent.
Launch animation →The Gut-Brain Axis: How Your Gut Talks to Your Brain
Follow the vagus nerve carrying signals up from your gut to your brain, the gut making most of your serotonin, and the microbiome shaping mood — then flip it and watch stress disrupt the gut.
Launch animation →How Memories Form: Synaptic Plasticity (LTP)
Watch two neurons that fire together wire together — the NMDA receptor detects the coincidence, calcium floods in, and the synapse strengthens into a memory — then block it with alcohol and watch the memory fail to form.
Launch animation →Balance & the Inner Ear: Vertigo & BPPV
Turn and tilt your head and watch the inner-ear canals and otoliths fire your sense of balance — then knock a crystal loose to trigger BPPV vertigo, and roll it back out with the Epley manoeuvre.
Launch animation →How the Eye Focuses: Near, Far & Why You Need Glasses
Watch the lens flatten for distance and round up for near reading — then make the eye too long for myopia or stiffen the lens with age, and slot in the exact lens that fixes each.
Launch animation →How Drug Tolerance & Dependence Develop
Watch a neuron pull receptors off the surface so a drug does less and less — tolerance — then stop suddenly and see everything rebound the opposite way into withdrawal, and taper slowly to recover safely.
Launch animation →The Pupil: Your Eye’s Aperture & the Light Reflex
Shine a light and watch both pupils snap shut together — the consensual reflex — then dim the room to open them, and see why a doctor’s penlight can reveal a brainstem emergency or an opioid overdose.
Launch animation →Why Chili Burns: Capsaicin & the TRPV1 Heat Sensor
Discover that chili isn’t hot — it hijacks your heat receptor to fake a burn — then reach for water and fail, milk and succeed, and see how the same trick turns nerve pain down in a capsaicin cream.
Launch animation →What Happens in a Stroke
Block a brain artery and watch the core die while the penumbra flickers on the edge — then reopen the clot and see why 'time is brain' means roughly 1.9 million neurons lost per minute.
Launch animation →What Happens in a Seizure
Tip the balance between excitation and inhibition and watch neurons fire in a runaway synchronous storm — then see how the seizure spreads and how medication damps it back down.
Launch animation →What Happens in a Migraine
Ride the slow wave of cortical spreading depression across the cortex, watch the trigeminal nerve dump CGRP and inflame the meninges — then block CGRP and calm the throb.
Launch animation →Digestion
Send a meal down the tract and watch enzymes and acid break carbs, protein and fat into absorbable units — with a pH meter that shifts from stomach to intestine.
Launch animation →Stomach Acid, pH & the PPI Trade-off
Run the proton pump that drives your stomach to pH 2, activate pepsin and free your B12 and iron — then take a PPI and watch the pH climb while the nutrients stop being released.
Launch animation →The Gut Barrier & Microbiome
Ferment fibre into butyrate and watch it tighten the gut wall — then starve the microbes of fibre and see them start eating your mucus layer instead.
Launch animation →How the Liver Detoxifies
Watch Phase I make a toxin more reactive and Phase II neutralise it — and see exactly why a juice cleanse changes nothing at all.
Launch animation →What Alcohol Does Inside Your Liver
Ethanol becomes acetaldehyde becomes acetate — and the NADH that piles up shuts down fat burning, stalls your blood sugar and drives up uric acid. Nothing speeds it up. Nothing.
Launch animation →Kidney Nephron
Follow blood into the glomerulus and see filtration and reabsorption turn 180 litres of filtrate into urine — then toggle dehydration or diabetes and watch it change.
Launch animation →Muscle Contraction
Release calcium, expose the actin binding sites, and watch myosin heads ratchet through the cross-bridge cycle to slide the filaments and shorten the sarcomere.
Launch animation →Bone Remodeling & Calcium
Watch osteoclasts tunnel and osteoblasts rebuild — then drop vitamin D and see PTH quietly strip calcium out of your skeleton to defend the blood level.
Launch animation →SGLT2: Why Diabetes Drugs Make You Pee Sugar
Watch the kidney reclaim every gram of glucose — until blood sugar passes the threshold and it spills into the urine, or an SGLT2-inhibitor drug dumps it there on purpose.
Launch animation →Thirst, ADH & How Your Body Guards Its Water
Get dehydrated and watch osmoreceptors fire thirst and ADH, opening aquaporins so the kidney reclaims water — then drink too much, or lose ADH in diabetes insipidus, and watch the urine run clear.
Launch animation →Bilirubin, Jaundice & Why Skin Turns Yellow
Follow a worn-out red cell’s pigment to the liver to be conjugated and sent out in bile — then block a step and watch bilirubin climb until the skin turns yellow, the way it does in newborns and gallstones.
Launch animation →Bile Acids: How You Digest Fat
Eat a fatty meal and watch bile squirt from the gallbladder to emulsify the fat into droplets lipase can attack — then block the bile and watch the fat, and the vitamins A, D, E and K, go straight through.
Launch animation →Peristalsis: How Food Actually Moves Through You
Push a bolus down the gut with a contract-behind, relax-ahead muscle wave run by the gut’s own 500-million-neuron brain — then switch to mixing, the housekeeper wave, or a stalled diabetic stomach.
Launch animation →How a Pill Travels Through You: ADME
Swallow a pill and follow it through absorption, the liver’s first-pass cut, distribution, CYP450 metabolism and kidney excretion — then block an enzyme with grapefruit and watch the levels climb.
Launch animation →Slow vs Fast: Your Two Kinds of Muscle
Recruit slow-twitch fibres for a steady hold and fast-twitch fibres for a sprint — see why one resists fatigue and one delivers power, and why aging steals the fast ones first.
Launch animation →How a Broken Bone Heals
Follow a break through its four stages — blood clot, soft cartilage callus, hard bony bridge, then the long remodel back to normal — and see what smoking, movement or missing calcium do to it.
Launch animation →How You Pee: The Bladder & Its Reflex
Fill the bladder, feel the urge build, then release the micturition reflex to void on command — and see why infants can’t hold it, why the prostate weakens the stream, and what an overactive bladder does.
Launch animation →How the Liver Keeps Your Blood Sugar Steady
Watch the liver bank glucose as glycogen after a meal and release it between meals to hold your blood sugar steady — then fast long enough to make new glucose from scratch, or watch diabetes over-pour it overnight.
Launch animation →Gout: How Uric Acid Crystals Attack a Joint
Watch uric acid climb past the point where it dissolves and stab needle-shaped crystals into a joint, igniting a red-hot gout attack — then lower it with allopurinol and watch the crystals melt away.
Launch animation →The Pancreas: Your Digestive Enzyme Factory
Pour amylase, lipase and protease plus bicarbonate into the gut to digest a meal — then block the duct with a gallstone and watch the enzymes switch on inside and digest the pancreas itself.
Launch animation →How Kidney Stones Form (and How to Prevent Them)
Watch minerals in concentrated urine crystallize and clump into a stone — then feel it drop into the ureter and block it (the worst pain there is), and learn why water and calcium actually prevent them.
Launch animation →Nausea & Vomiting: The Body’s Eject Button
Watch four alarm lines — the gut, a blood-sampling brain zone, the inner ear and the mind — converge on the vomiting centre and fire the eject reflex, then calm each with its matching anti-sickness drug.
Launch animation →Osmosis & Tonicity: Why Cells Swell or Shrink
Drop a cell into salty or plain water and watch it shrivel or swell to bursting as water chases solute — then see why an IV bag has to be mixed to just the right strength.
Launch animation →How Cavities Form
Feed the plaque bacteria sugar and watch the acid they make dissolve enamel from below the surface — then brush with fluoride and watch the tooth re-harden before a cavity breaks through.
Launch animation →How a Joint Works & What Goes Wrong
Bend a healthy joint gliding on smooth cartilage — then wear the cushion away, watch bone grind on bone and spurs form, and see what actually eases an arthritic joint.
Launch animation →Vitamin D: From Sunlight to Hormone
Fire UVB photons at your skin and follow the molecule through the liver and kidney into an actual steroid hormone that walks into the nucleus and switches genes on.
Launch animation →Vitamin B12's Impossible Journey
Five stages, two carrier proteins, a working stomach, a working pancreas and one specific stretch of gut. Break any link — a PPI, metformin, pernicious anaemia — and absorption collapses.
Launch animation →Vitamin C, Collagen & Why Sailors Fell Apart
Zip three protein chains into the strongest rope in biology — then take the vitamin C away and watch the helix unravel, and old, healed scars split back open.
Launch animation →Magnesium: The Mineral That Makes ATP Work
Bare ATP is useless — enzymes reject it. Watch magnesium clamp the phosphates and switch it on, plug the NMDA channel, and let a cramping muscle finally let go.
Launch animation →Calcium Control: PTH, Vitamin D & Your Blood Level
Watch four tiny parathyroid glands defend your blood calcium — pulling it from bone, kidney and gut with PTH and vitamin D — then drop your vitamin D and see PTH climb and quietly rob the skeleton.
Launch animation →Vitamin K, Clotting & How Warfarin Works
Watch vitamin K get recycled to switch on the clotting factors — then block the recycling enzyme with warfarin and see the factors go dark over days, or override it with a plate of greens.
Launch animation →Immune Response
Inject a pathogen and watch innate cells swarm, T cells activate B cells, and antibodies rise — then vaccinate and compare the fast, strong secondary response.
Launch animation →Inflammation: The Cascade and How It Resolves
Cut the tissue and watch NF-κB light the fire, neutrophils swarm and CRP climb — then discover that resolution is an active programme driven by omega-3 resolvins, not the fire simply burning out.
Launch animation →Histamine, Mast Cells & Allergy
Arm a mast cell with IgE, then let the allergen cross-link it and watch histamine burst out to raise a wheal — then block the H1 receptor with an antihistamine and see the symptoms fall while the histamine still pours out.
Launch animation →Fever & the Body’s Thermostat
Watch an infection turn the hypothalamic thermostat up on purpose — you shiver to reach the new set-point, then take an antipyretic and sweat as it drops back. A fever is regulated, not the thermostat breaking.
Launch animation →The Complement System: Your Blood’s Silent Army
Watch three trigger pathways converge to tag a bacterium, punch it open with the membrane-attack complex, and call in inflammation — then lose the self-protection proteins and see complement turn on your own cells.
Launch animation →How a Wound Heals: The Four Overlapping Phases
Follow a cut through all four phases — platelet plug, immune clean-up, collagen and new vessels filling the gap, then the long remodel into a scar — and watch diabetes or low vitamin C stall it.
Launch animation →How Vaccines Train Your Immune System
Show your immune system a harmless preview of a germ and watch it build memory cells — then meet the real thing and see the fast, strong secondary response stop it before you feel sick.
Launch animation →How Bacteria Beat Antibiotics
Kill a colony with an antibiotic and watch a single resistant mutant survive and take over — then see bacteria destroy the drug with enzymes and pass resistance genes to their neighbours on plasmids.
Launch animation →Anaphylaxis & the EpiPen: An Allergy Emergency
Watch a whole-body allergic reaction crash the blood pressure and slam the airways shut — then give epinephrine and see it reverse both, and learn why antihistamines alone can’t.
Launch animation →Biofilms: Why Some Infections Won’t Clear
Watch free bacteria stick to a surface and build a slime fortress that antibiotics and immune cells can’t break into — the reason dental plaque, catheter and implant infections just won’t clear without removing them.
Launch animation →Sweat: How Your Body Cools Itself
Overheat and watch millions of glands pump sweat that cools you only as it evaporates — then crank up the humidity so it can’t evaporate, the core climbs, and the body tips toward heat stroke.
Launch animation →Cryotherapy: How Cold Changes Your Body
Press cold onto the skin and watch the arteriole clamp shut and the pain nerve slow to a crawl until the ache fades — then push too far and ice crystals form, the very trick a surgeon uses on purpose to freeze off a wart or a tumour.
Launch animation →Stem Cells: The Body's Blank Slates
Take a blank stem cell and coax it down branching paths into blood, nerve or muscle — then see the real difference between embryonic, adult, and reprogrammed iPS cells.
Launch animation →Autoimmunity: When Defence Turns on You
Watch immune cells lose the ability to tell self from invader and attack the body's own tissue — then see how tolerance normally prevents it and why it sometimes breaks down.
Launch animation →Why animated?
Textbook diagrams freeze a moving process into a single still frame — and biology is almost never still. Energy production, blood flow, filtration, and nerve signals are all processes, defined by what moves where and when. These visualizations let you press play, slow the speed down, and see cause and effect unfold, which is how the brain actually builds an intuition for a mechanism. More visualizations are added over time.
How to read them
Every page works the same way. Pause and Speed are always in the top-left. Each page also plays sound that follows the mechanism — a heartbeat, a nerve spike, a droplet crossing a membrane — and the 🔊 Sound button mutes it (your choice is remembered across the whole site). The scenario buttons are the interesting part — they let you break the mechanism on purpose and watch what fails, which is usually the fastest way to understand why the healthy version is built the way it is. The panel on the right shows live numbers in real clinical units, and each page says plainly which figures are real measured values and which are an illustrative model. Below every animation there is a full plain-language article, written for patients rather than clinicians.
These pages are free, carry no advertising, and are not a substitute for medical advice. They exist because understanding how your own body works should not cost anything.