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Circadian system in adolescents and the use of light therapy
Kučerová, Jana ; Červená, Kateřina (advisor) ; Pačesová, Dominika (referee)
Circadian rhythms, as regularly recurring events in living organisms with a period of approximately 24 hours, are an important part of life on Earth. To keep the period of the internal circadian clock of an organism in line with the cycle of the Earth Day, synchronization of this clock is necessary. The most important factor in synchronizing the circadian clock is light, which provides the brain with information about the phase of the Earth Day. The individual setting of the circadian clock, which is manifested in the form of a chronotype, has a profound effect on the life of the individual. Chronotypes change throughout life, and the most significant changes occur during adolescence, when the overall chronotype shifts. This results in adolescents going to bed later even though they have to get up early for school. This is also why they are more likely to suffer from sleep deprivation, be inattentive at school or fall asleep during lessons. Consequently, they experience, often with significant, social jet lag, which is a health risk. Light therapy offers a solution. This paper presents its general use, as well as specific examples of its use with delayed adolescents. However, there are also other ways to improve the situation of adolescents, e.g., delaying the start time of school in the morning,...
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Significance of the timekeeping system for human health
Pospíšilová, Lucie ; Sumová, Alena (advisor) ; Hejnová, Lucie (referee)
The circadian system evolved as an adaptation to cyclic changes in external conditions on Earth, mainly the alternation of light and dark with a period of solar day. The rhythmic signal is generated at the cellular level and it is controlled by rhythmic expression of clock genes and their protein products. In mammals, the hypothalamic suprachiasmatic nuclei (SCN) are the principal circadian oscillator coordinating daily cycles of physiology and behavior, while in peripheral tissues local oscillators operate. The peripheral oscillators are entrained to the daytime and also among each other, by neuroendocrine signals from the SCN. Mutual synchrony of all the circadian components is necessary for proper function of the organism. The main entraining cue of the circadian system with environment is light, which affect the SCN via retina. In a subgroup of blind people sensing the light in the retina is disturbed and their circadian system cannot be synchronized by light. The SCN controls rhythmic production of melatonin in the pineal gland. This hormone mediates the information about the daytime to other tissues in the body, which are not photosensitive. The circadian system temporally drives many processes, including the cell division cycle. It seems that disruption of the temporal regulation could contribute to...
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Significance of the timekeeping system for human health
Pospíšilová, Lucie ; Sumová, Alena (advisor) ; Hejnová, Lucie (referee)
The circadian system evolved as an adaptation to cyclic changes in external conditions on Earth, mainly the alternation of light and dark with a period of solar day. The rhythmic signal is generated at the cellular level and it is controlled by rhythmic expression of clock genes and their protein products. In mammals, the hypothalamic suprachiasmatic nuclei (SCN) are the principal circadian oscillator coordinating daily cycles of physiology and behavior, while in peripheral tissues local oscillators operate. The peripheral oscillators are entrained to the daytime and also among each other, by neuroendocrine signals from the SCN. Mutual synchrony of all the circadian components is necessary for proper function of the organism. The main entraining cue of the circadian system with environment is light, which affect the SCN via retina. In a subgroup of blind people sensing the light in the retina is disturbed and their circadian system cannot be synchronized by light. The SCN controls rhythmic production of melatonin in the pineal gland. This hormone mediates the information about the daytime to other tissues in the body, which are not photosensitive. The circadian system temporally drives many processes, including the cell division cycle. It seems that disruption of the temporal regulation could contribute to...
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