Interactive lab

Four core activities

Every activity uses real chapter content and keeps your progress in both study modes. Each also appears inside the topic where it helps most.

Centerpiece

Break the neutrophil pathway one inherited defect at a time; predict blood and tissue before the reveal.

In context: 2.3 Find the broken step →

Centerpiece · Recruitment and killing lab

Find the broken step

A neutrophil has six jobs between the blood and a dead bacterium. Pick a defect, read what is molecularly wrong, and predict where the cell stops, what the blood count does and what the infected tissue looks like. Only then does the lab show you.

0 of 5 defects worked out.

A neutrophil leaving a venule: rolling, adhesion, transmigration, chemotaxis, phagolysosome and killing123456

Step 1 · Rolling

E-/P-selectin ↔ sialyl-Lewis X; L-selectin

Selectins on activated endothelium catch sugar ligands on the neutrophil. Bonds form and break, so the cell tumbles slowly along the venule wall.

Tap each step to see its molecules. When the sequence is clear, choose defect 1 above and break it.

Transfer round · same mechanisms, new wording

Work out all five defects above to open five short cases that describe them in different words.

Causal chains

Six chains: vascular, fever, airway, oxidative burst, granuloma loop, resolution.

In context: 2.1, 2.3, 2.4, 2.5, 2.6 →

Core activity · The Missing Arrow

The Missing Arrow

Complete the causal chain. Place the missing step by dragging a card onto a gap, or tap a card and then tap the gap. Some gaps need an event; others need the mechanism that links one event to the next.

A bee stings the back of a hand. Complete the chain from the first mediator to leukocytes lining the venule wall.

Two gaps ask for a mechanism (how one event causes the next); three ask for an event (what you would see).

  1. Mast cells around the sting degranulate and release histamine
  4. histamine also makes endothelial cells of postcapillary venules contract
  7. Flow slows in the small vessels: stasis
  8. in slow flow, leukocytes drift out of the central stream

Cards

Tap or drag a card. Placing a used card moves it.

Look-alikes

Granuloma vs granulation tissue, caseating vs non-caseating, hypertrophic scar vs keloid, exudate vs transudate.

In context: 2.1, 2.6, 2.7 →

Core activity · Almost Twins

Almost Twins

Two look-alikes side by side. Decide what they share, then pick the clue that separates them and say why it works.

Look-alike A

Granuloma

Lecture image

Tight nodule of pale epithelioid macrophages without central necrosis, ringed by lymphocytes
Lymph node in sarcoidosis (lecture image).
  • Contains macrophages
  • Compact nodule of epithelioid macrophages, giant cells, lymphocyte cuff
  • Driven by IL-12 → Th1 → IFN-γ; TNF holds it together
  • Purpose: contain an agent that cannot be destroyed

Step 1 · What they share

What do these two share?

Select every feature that both show.

Case reasoning

Change the day, the closure, the history or the biopsy, and decide whether the answer moves.

In context: 2.1, 2.2, 2.6, 2.7 →

Core activity · One Fact Changes

One Fact Changes

Answer a case and name the decisive clue. Then exactly one fact changes. Decide whether the answer moves, and why.

1 · The original case

A 64-year-old man with diabetes has crushing chest pain. His occluded left anterior descending artery cannot be opened in time. He dies of an arrhythmia 2 days later. The anterior wall is examined microscopically.

What dominates the infarcted myocardium?

Which fact decided it?