PIRL Experimental · Interactive life science
How does a cut heal?
Follow the repair. Change one condition. Look for evidence.
1. A bleeding cut
Model time · 0.0 sSmall blood vessels are damaged. Blood cells and plasma escape into the gap. Press Play to begin.
- 1 · Bleeding
- 2 · Clot forms
- 3 · Protective cover
- 4 · Cells divide & move
- 5 · Surface closes
- 6 · Healed surface
Time is compressed into animation seconds. Sizes, cell numbers, and rates are illustrative; they do not predict real healing time.
Compare the repair
Solid orange: your trial. Dashed navy: the default trial at the same model time. Playback speed changes viewing speed only.
Your trial: 0% closed · Default: 0% closed.
Try a controlled comparison
Each preset restarts the model. Watch a default trial, then change just one condition.
- Predict what will change and why.
- Pause at the same model time in both trials.
- Compare the gap, blood delivery, and newly formed cells.
- Explain your result using evidence from the model.
Record observations & download results
Capture the current state, change one factor, and compare. Records stay here until you clear them or close this page.
| Trial / time | Gap closed | Conditions | Scab picks |
|---|---|---|---|
| No observations yet. | |||
CSV includes the settings, stage, and model time for each observation. No student information is collected.
What this model shows—and what it simplifies
- Closing is not the same as clotting. Platelets and fibrin help form a clot. The clot does not turn into skin. New tissue forms beneath the cover.
- Cells divide and move. The highlighted edge cells make new cells; skin cells also migrate over the wound. Cells in deeper tissue help lay down and reorganize supporting material.
- Blood supports the repair. The vessel is enlarged and moved close to the action to make delivery visible. The epidermis itself has no blood vessels; materials reach it from underlying tissue.
- The stages overlap. The six labels organize the animation. Clotting, immune activity, growth, and remodeling do not wait in a perfect queue in a real wound.
- More is not always better. Supply sliders plateau at sufficiency. Extreme zero settings are hypothetical teaching conditions; the model does not simulate tissue death, medical treatment, or whole-body illness.
- The final frame shows a healed surface. Deeper remodeling takes longer, and repaired tissue may retain a scar. This model does not regrow severed nerves or promise restoration of the original strength.
- Picking is a setback. The button removes the cover and damages some new tissue in this model. Changing the infection menu changes an experimental assumption; it is not a treatment action.
This is a qualitative learning model, not medical advice. The effects are chosen to make relationships visible, not calculated from a clinical dataset.
Science references: Cedars-Sinai: How wounds heal; American Academy of Dermatology: Wound care and scarring; MedlinePlus: How wounds heal.
See the drawings that inspired the simulation
Your eye can follow the same idea through different forms: an original tissue sketch, a digital cross-section, and drawings of the healing sequence. These supplied illustrations are the starting materials; the live model adds movement and refines the science.