biological clock

[ bahy-uh-loj-i-kuhl klok ]

noun

, Physiology.

1. Also called bod·y clock [bod, -ee klok]. an innate mechanism of the body that regulates its periodic cycles or biorhythms, such as the sleep-wake cycle. chronotype ( def ), circadian ( def ).
2. an innate mechanism regulating the passage of an organism through the natural stages of its life, especially with reference to the reproductive stage of a woman's or man's life or the approaching end of this stage:

   My biological clock is ticking, but I don't feel ready to have kids!

biological clock

noun

1. an inherent periodicity in the physiological processes of living organisms that is not dependent on the periodicity of external factors
2. the hypothetical mechanism responsible for this periodicity

biological clock

/ bī′ə-lŏj′ĭ-kəl /

1. An internal system that controls an organism's circadian rhythms, the cycles of behavior that occur regularly in a day. In mammals, the biological clock is located near the point in the brain where the two optic nerves cross. In many birds, the biological clock is located in the pineal gland. In protists and fungi, the individual cells themselves regulate circadian rhythms.

biological clock

1. The innate rhythm of behavior and body activity in living things. A twenty-four-hour cycle of body activity, which operates in some organisms, is called the circadian rhythm .

Notes

Although the term biological clock refers to all innate timing mechanisms, it is often used when describing certain body functions that are subject to this rhythm, such as the loss of fertility with age.

Word History and Origins

Origin of biological clock¹

First recorded in 1950–55

Example Sentences

However, stress can speed up the biological clock, making people more vulnerable to aging-related diseases, from cardiovascular disease to diabetes and dementia.

From Salon

However, like all living things, plants are subject to a circadian rhythm -- the biological clock that runs through day and night cycles and influences biological processes.

From Science Daily

These results imply that the expression rhythms of genes controlled by the biological clock are sensitive to environmental changes, and can be influenced by genetic changes that result from environmental adaptation.

From Science Daily

Some proteins had rhythms closely tied to the master biological clock, which keeps the body on a 24-hour rhythm.

From Science Daily

So much for beating the biological clock, as promised by a multimillion-dollar industry that promoted its technologies in part as a way for women to avoid detrimental career disruptions.

From Los Angeles Times

Related Words

• circadian rhythm