Vision without sight
Article Abstract:
New research shows that some blind persons may be able to process light, even though they do not consciously perceive it. Their hormonal response to light may allow them to synchronize their bodies to a 24-hour circadian rhythm. Humans entrain, or synchronize, their bodies to the 24-hour day through the influence of light and dark. Blind persons who cannot perceive light may establish a sleep-wake rhythm close to the 24-hour day, but cannot control their circadian pacemakers, which are regulated by the rhythm of melatonin secretion. Some blind persons retain functioning photoreceptors and retinohypothalamic tracts, both of which influence the circadian rhythm by influencing levels of melatonin secreted at night. Recurring insomnia may be experienced by blind persons when their rhythm of melatonin secretion does not correspond to the 24-hour day.
Publication Name: The New England Journal of Medicine
Subject: Health
ISSN: 0028-4793
Year: 1995
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Reprodutive and morphological condition of wild mink (Mustela vision) and river otters (Lutra canadensis) in relation to chlorinated hydrocarbon contamination
Article Abstract:
Mink and river otters were examined for chlorinated hydrocarbon contamination on the Columbia and Fraser river systems in British Columbia. Research showed the populations did not appear to be physiologically or reproductively compromised by chlorinated hydrocarbon accumulation, however there was a significant negative correlation between polychlorinated biphenyls (PCBs) concentration and mink baculum size.
Publication Name: Environmental Health Perspectives
Subject: Health
ISSN: 0091-6765
Year: 1999
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Circadian rhythms
Article Abstract:
Circadian rhythms respond to external influences or zeitgeber to regulate body temperature, hormone production, the cardiovascular system, pain tolerance and acceptance of medication. Each person has more than 100 circadian rhythms.
Publication Name: Mayo Clinic Health Letter
Subject: Health
ISSN: 0741-6245
Year: 1995
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