MODEL RELEASED. Biological clock. Abstract image depicting human biorhythms,showing a clock super- imposed on a woman's face. Many biological processes are believed to take place under the direction of an internal clock mechanism. These processes vary in a rhythmic way (for example the menstrual cycle,which repeats itself about every 28 days in fertile women and has often been associated with the moon's cycle). Most bio- rhythms,sleeping and waking for example,are based on a daily or circadian (24-hour) cycle and are regulated by hormones such as melatonin and cortisol. The fertile lifespan of a woman is also sometimes portrayed as a biological clock | |
Lizenzart: | Lizenzpflichtig |
Credit: | Science Photo Library / Burriel, Oscar |
Bildgröße: | 4919 px × 3628 px |
Modell-Rechte: | vorhanden |
Eigentums-Rechte: | nicht erforderlich |
Restrictions: |
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