Listen&Learn: Circadian rhythms

Learn how the body keeps track of time.

Pre-listening vocabulary

• detect: to notice or observe something
• signal: a communication of instructions
• hormone: a chemical substance made in the body
• sufficient: enough of something
• disrupt: to cause something to stop functioning properly

Listening activity

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Gapfill exercise

A circadian rhythm is a clock that helps control our bodily processes. Humans’ circadian rhythms keep track of time by detecting in the light. When the sky becomes dark enough, the receives a signal to produce melatonin, a hormone that helps us fall asleep. However, not all circadian rhythms are the same, and some people’s brains do not produce sufficient melatonin until later in the night. People who naturally stay awake later often with the early work and school hours of modern society. Circadian rhythms can also be disrupted by unnatural light, such as the blue light that comes from screens. For this reason, many people getting less sleep than they need.

Comprehension questions

1. Circadian rhythms respond to changes in
   a. light
   b. temperature
   c. gravity
   
2. Melatonin is a hormone that helps with
   a. energy
   b. memory
   c. sleep
   
3. Some people struggle to fall asleep because
   a. their brains make too much melatonin
   b. their brains make melatonin later in the night
   c. their brains make melatonin too early in the day

See answers below

Discussion/essay questions

1. Do you think you get enough sleep? Why or why not? What are your sleeping habits?
2. Do you think it’s possible for society to accommodate for people with different sleeping patterns?

Transcript

A circadian rhythm is a natural clock that helps control our bodily processes. Humans’ circadian rhythms keep track of time by detecting changes in the light. When the sky becomes dark enough, the brain receives a signal to produce melatonin, a hormone that helps us fall asleep. However, not all circadian rhythms are the same, and some people’s brains do not produce sufficient melatonin until later in the night. People who naturally stay awake later often struggle with the work and school hours of modern society. Circadian rhythms can also be disrupted by unnatural light, such as the blue light that comes from screens. For this reason, many people report getting less sleep than they need.

Answers to comprehension questions

1a 2c 3b