Immunology: Why the Thymus Culls Most of Its Recruits
How your body tells friend from foe, from the first-line defenses you were born with to antibodies, memory, vaccines, allergies and autoimmunity.
Try 3 questions
1. During an infection, what actually causes a fever?
- Bacteria give off heat as they multiply
- Immune signals reset the brain's thermostat
- Muscles overheat from fighting the germs
Show the answer
Answer: Immune signals reset the brain's thermostat
Cytokines such as interleukin-1 prompt the hypothalamus to raise its temperature set point; the body then conserves and generates heat, which is why you shiver.
2. Pus is mostly made of what?
- Lymph fluid leaking from vessels
- Dead neutrophils and tissue debris
- Dead bacteria and nothing else
Show the answer
Answer: Dead neutrophils and tissue debris
Neutrophils rush to infection sites in huge numbers, engulf microbes and die within hours; their remains, with debris and fluid, form pus.
3. How do innate immune cells recognize microbes they have never encountered before?
- They detect molecular patterns many share
- They carry ready-made antibodies for each
- They remember them from past infections
Show the answer
Answer: They detect molecular patterns many share
Receptors such as Toll-like receptors recognize structures common to whole groups of microbes, like bacterial cell-wall components or viral RNA, without any prior exposure.
The whole quiz comes before your apps
BrainTok asks a few questions like these before the apps you choose open, so your screen time turns into learning. For iPhone.
Join the beta