Body has daily activity patterns {circadian rhythm}|. Internal mechanisms for daily cycles have 24-hour cycles.
functions
Body temperature, activity, blood pressure, blood pulse rate, blood volume, hormone levels, eosinophil levels, ACTH concentration, cortisol concentration, magnesium concentration, calcium concentration, 17-hydroxycorticosteroid concentration, sodium concentration, potassium concentration, catecholamine concentration, and phosphate concentration vary over day.
functions: time of day
Labor is most frequent and T lymphocytes are most at 1 AM. Growth hormone and deep sleep are greatest at 2 AM. Asthma attacks are most frequent at 4 AM. Body temperature is lowest at 4:30 AM. Menstruation starts most frequently at 6 AM. Insulin, blood pressure, heart rate, and cortisol are lowest at 6 AM, but melatonin is highest. Blood pressure starts to rise at 6:45 AM. Hay fever is worst at 7 AM. Melatonin production stops at 7:30 AM. Heart attack and stroke are most frequent at 8 AM. Rheumatoid arthritis is worst at 8 AM. T lymphocytes are fewest at 8 AM. Bowel movements are most likely at 8:30 AM. Alertness is highest at 10 AM. Blood hemoglobin concentration is highest at 12 PM. Coordination is best at 2:30 PM. Respiration is fastest, reflexes are quickest, and hand grip is strongest at 3 PM to 3:30 PM. Body temperature, heart rate, and blood pressure are highest at 4 PM. Muscle strength is greatest at 5 PM. Urination is most frequent at 6 PM. Blood pressure is highest at 6:30 PM. Body temperature is highest at 6:30 PM. Sensitivity to pain is greatest at 9 PM. Melatonin production starts at 9 PM, induces sleep at night, and maximizes just before morning. Bowel movements stop at 10:30 PM. Allergic reaction is most frequent at 11 PM.
cycle
Light affects retinal ganglion-cell melanopsin receptors, which catabolize PERIOD (PER) and TIMELESS (TIM) protein complexes in cytoplasm. Six hours later, catabolism is complete and CYCLE and CLOCK proteins bind. Then combined proteins bind to PER and TIM genes in cell nucleus, to start transcription. Six hours later, PER and TIM proteins bind in cytoplasm to form complex that blocks binding of CYCLE and CLOCK in cell nucleus.
Biological Sciences>Zoology>Kinds>Mammal>Rhythm
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Date Modified: 2022.0224