Back to topics

How does your gut tell your brain you have eaten enough?

You can stop eating before every nutrient has been absorbed. Stretch in the gut and chemical signals help coordinate the end of a meal, while other signals affect appetite over longer periods. Explore how the body combines these messages rather than relying on a single fullness switch.

3–7 min

Questions you could explore

  • What information can a stretch signal provide that a nutrient signal cannot?
  • How can signals from the gut and signals about stored energy contribute on different timescales?

Start reading

Ready to try your ideas aloud?

Your topic carries over. Record up to 2½ minutes, depending on your plan.

Health and the body

Daylight and the body's clock

Even in a room with no clocks, your body follows an internal roughly 24-hour schedule of sleepiness, hunger, and alertness. Those internal daily rhythms respond to outside cues, with morning and evening light helping reset and coordinate the body's master clock.

3–5 min
Health and the body

How vaccines build immune memory

The first time the immune system encounters an unfamiliar antigen, building a response takes time. Vaccines help develop recognition and memory before a later encounter with a pathogen. Different types introduce antigens or instructions for making them in different ways, offering a starting point for exploring how immune memory works.

4–5 min
Health and the body

Antibiotics and the viruses they cannot treat

Antibiotics can treat certain bacterial infections, but they do not treat the viruses that cause a common cold. Because bacteria are living cells with their own metabolic machinery and viruses are tiny genetic packages that hijack your cells, an antibiotic that disables bacteria has no matching target in the viruses that cause a cold.

2–3 min
How does your gut tell your brain you have eaten enough? | Speech Topic | speaking.app