Nature: The Human Body 2

– The Body Clock –

The circadian rhythm, an inherent biological function in humans, plays an instrumental role in our overall health and well-being. This internal clock, which operates on an approximately 24-hour cycle, regulates various physiological processes such as sleep, feeding, hormone production, and cell regeneration.

Originating from the Latin words “circa diem”, meaning “around a day”, the circadian rhythm is influenced by external cues like light and temperature. The suprachiasmatic nucleus (SCN), a group of cells in the brain’s hypothalamus, functions as the master clock, synchronizing the body’s circadian rhythms based on these environmental signals.

A well-regulated circadian rhythm promotes optimal sleep quality and other biological functions, whereas a disrupted rhythm can lead to sleep disorders, obesity, depression, and other health issues. Modern lifestyle habits, including prolonged screen time and irregular sleep schedules, often disrupt our circadian rhythms, underscoring the importance of maintaining a consistent sleep-wake cycle for optimal health. Advances in the study of circadian rhythms have the potential to revolutionize our understanding of human health and disease.

Choose NO MORE THAN TWO words from the text for each answer.

The circadian rhythm is an internal ______ that operates on an approximately 24-hour cycle.
This biological function regulates sleep, feeding, hormone ______, and cell regeneration.
The circadian rhythm is influenced by ______ cues such as light and temperature.
The suprachiasmatic nucleus in the hypothalamus functions as the master ______, synchronizing the body’s circadian rhythms.
A disrupted circadian rhythm can lead to sleep disorders, obesity, depression, and other ______ issues.
Modern lifestyle habits, including prolonged screen time and irregular sleep schedules, often ______ our circadian rhythms.

Choose NO MORE THAN ONE word from the text for each answer.

The circadian rhythm, a natural ______ within humans, plays a pivotal role in our health. Operating on a near 24-hour cycle, it controls diverse bodily processes, including sleep, feeding, hormone ______, and cell renewal. Influenced by external factors such as light and temperature, the master ______ in the brain’s hypothalamus, known as the suprachiasmatic nucleus, aligns the body’s circadian rhythms. An unbalanced circadian rhythm can result in sleep disorders, obesity, depression, and other health ______. Modern habits, such as extended screen time and inconsistent sleep schedules, often ______ these rhythms, emphasizing the importance of a regular sleep-wake cycle.

Vocabulary Builder

Find the synonyms (words with the same or similar meaning) to these 9 words from the original passage.

Original Word	Variants Used
circadian rhythm	____________ / ______________
regulates	____________ / ______________
environmental cues	__________________________
suprachiasmatic nucleus	__________________________
health	__________________________
disrupted	____________ / ______________
health complications	__________________________
lifestyle habits	__________________________
interfere with	__________________________

Reveal answer (19 More Words)

Original Word	Variants Used
circadian rhythm	internal clock, natural mechanism
regulates	controls, aligns
environmental cues	external factors
suprachiasmatic nucleus	master clock
health	bodily processes
disrupted	unbalanced, misaligned
health complications	health issues
lifestyle habits	modern habits
interfere with	disrupt