Defence & Repair
The body’s boundary, and what happens when something crosses it — innate and adaptive immunity, complement, the inflammation cascade, histamine and anaphylaxis, fever and sweating — then the wound-healing, skin, hair and stem-cell machinery that rebuilds tissue afterwards. Antibiotic resistance and bacterial biofilms are here too, as the other side of the same contest.
Every page here is a hands-on animated diagram, not a video — press play, slow it down, break the mechanism on purpose, and read the live values in real clinical units. They explain how a process works; they are not medical advice, and the evidence for any treatment lives on the topic pages each animation links into.
Table of Contents
The Animations (17)
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 →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 →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 →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 →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 →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 →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 →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 →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 →Cyclospora: From Contaminated Field to Relapsing Illness
Follow the parasite behind the 2026 lettuce recall from irrigation water to your gut — rinse the leaves and watch it survive, chill the field so it never ripens, then treat it with the drug that works and the one that cannot.
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 →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 →Hair Growth, Thinning and Why Hair Falls Out
Run a scalp of follicles through anagen, catagen and telogen, then shrink them with DHT year by year — or dump them all into shedding three months after a stressor.
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 →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 →Sunburn, Tanning and What UV Actually Does to Your Skin
Rain UVB photons onto skin and watch DNA kink into dimers — repaired, or fatal to the cell, or banked as a mutation forever — then put sunscreen on and count how many never land.
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 →