CHRONOBIOLOGY

Chronobiology is a field of biology that examines periodic (cyclic) phenomena in living organisms and their adaptations to solar and lunar related rhythms.

1. KUVEMPU UNIVERSITY PG Department of Studies and Research in Biotechnology Sahyadri Science College, Shivamogga Seminar Topic CHRONOBIOLOGY Guide, Dr.Pallavi M Lecturer PG dept. Of Biotechnology Sahyadri Science college Shivamogga By, RAMYA A M I MSc, I Sem PG dept. Of Biotechnology Sahyadri Science college Shivamogga 1

2. CONTENT INTRODUCTION HISTORY CHRONOBIOLOGY TYPES OF RHYTHMS CIRCADIAN RHYTHMS HUMAN CIRCADIAN RHYTHM NOBEL PRIZE IN PHYSIOLOGY OR MEDICINE MECHANISM TO CONTTOL CIRCADIAN RHYTHM CHRONOTHERAPY CONCLUSION REFERENCE

3. INTRODUCTION Chronobiology comes from the ancient Greek ( chronos meaning time ) and biology which pertains to the study or science of life. Chronobiology refers to the day-night cycle that affects the humans and other organisms when the Earth rotates. Chronobiology is a field of biology that examines periodic (cyclic) phenomena in living organisms and their adaptations to solar and lunar related rhythms. These cycles are known as biological rhythms. A diverse range of species, from Cyanobacteria to Humans, evolved endogenous biological clocks that allow for the anticipation of daily variations in light and temperature.

4. HISTORY A circadian cycle was first observed in the 18th century It is observed by the D ’Ortous and de Mairan They reported daily leaf movements of the Mimosa pudica Through the experimentation they w ere able to show that the leaves continue to swing in a circadian rhythm, even in permanent darness.

5. CHRONOBIOLOGY CHRONOBIOLOGY is a field of biology that examines periodic phenomena in living organisms and their adaptations to solar and lunar related rhythms These occur (a) in animals (eating, sleeping, mating, hibernating, migration, cellular regeneration, etc.), (b) in plants (leaf movements, photosynthetic reactions, etc.), and in microbial organisms such as fungi and protozoa. They have even been found in bacteria, especially among the cyanobacteria (blue-green algae).

6. TYPES OF RHYTHMS Infradian Rhythms Circadian Rhythms: A Circadian rhythm can further be broken down into routine cycles during the 24-hour day: Diurnal, which describes organisms active during daytime. Nocturnal, which describes organisms active in the night. Ultradian Rhythms

7. INFRADIAN RHYTHM In Chronobiology, an Infradian rhythm is a rhythm with a period longer than the period of a circadian rhythm, such as menstruation, breeding, tidal or seasonal rhythms.

8. Ultradian rhythm In Chronobiology, an ultradian rhythm is a recurrent period or cycle repeated throughout a 24-hour day, the Oxford English Dictionary's definition of Ultradian specifies that it refers to cycles with a period shorter than a day but longer than an hour. The descriptive term Ultradian is used in sleep research in reference to the 90–120 minute cycling of the sleep stages during human sleep. Other Ultradian rhythms include blood circulation, blinking, and pulse, hormonal secretions such as growth hormone,

9. CIRCADIAN RHYTHM Circadian rhythms are well-defined biological rhythmic activities ongoing 24-h time in human metabolism. Circadian rhythms, which take those 24 h, are examined in two parts: as nocturnal and diurnal rhythm. Nocturnal rhythm describes changes in the biological rhythm of the night, and diurnal rhythms refer to the biological rhythms that occur during the day

10. HOW DOES IT WORK? A master clock in the brain coordinates all the biological clocks in a living thing, keeping the clocks in sync. In vertebrate   animals, including humans, the master clock is a group of about 20,000  nerve cells  (neurons) that form a structure called the suprachiasmatic nucleus, or SCN. The SCN is in a part of the brain called the hypothalamus and receives direct input from the eyes.

11. What factors can change circadian rhythms? Changes in our body and environmental factors can cause our circadian rhythms and the natural light-dark cycle to be out of sync. For example: Mutations or changes in certain genes can affect our biological clocks. Jet lag or shift work causes changes in the light-dark cycle. Light from electronic devices at night can confuse our biological clocks. These changes can cause sleep disorders, and may lead to other chronic health conditions, such as obesity, diabetes, depression, bipolar disorder, and seasonal affective disorder.

12. MELATONIN

13. NOBEL PRIZE IN PHYSIOLOGY OR MEDICINE Jeffrey C. Hall, Michael Rosbash and Michael W. Young awarded Nobel prize for their discoveries of molecular mechanisms controlling the circadian rhythm in 2017. Using fruit flies as a model organism, they isolated a gene that controls the normal daily biological rhythm. They explained a Mechanism to control the circadian rhythm

14. Mechanism to control the circadian rhythm

15. CHRONOTHERAPY How do circadian rhythms affect health? Circadian rhythms can influence important functions in our bodies, such as: Hormone  release Eating habits and digestion Body temperature

16. CONCLUSION

17. REFERENCE Nelson RJ. 2005. An Introduction to Behavioral Endocrinology. Sinauer Associates, Inc.: Massachusetts. Leon Kreitzman; Russell G. Foster (2004). Rhythms of life: the biological clocks that control the daily lives of every living thing. New Haven, Conn: Yale University Press. ISBN 0-300 10969-5. Zivkovic, Bora (2006-07-03). "ClockTutorial #2a, Forty-Five Years of Pittendrigh's Empirical Generalizations"(http://scienceblogs.com/clock/2006/07/clocktutorial_3_fortyfive_year.php)A Blog Around the Clock. ScienceBlogs. Retrieved 2007-12-23.

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