Diseases, Conditions, Syndromes

How important is speech in transmitting coronavirus?

Normal speech by individuals who are asymptomatic but infected with coronavirus may produce enough aerosolized particles to transmit the infection, according to aerosol scientists at the University of California, Davis. Although ...

Oncology & Cancer

Eye and the scalpel: Ocular tumors easier to diagnose noninvasively

Australia is the sunniest continent on Earth—which is why it also has the highest rates of skin cancer. But plentiful sunlight is also likely responsible for the lesser known ocular surface cancer, which occurs when abnormal ...

Diseases, Conditions, Syndromes

Low risk of coronavirus spreading through tears

While researchers are certain that coronavirus spreads through mucus and droplets expelled by coughing or sneezing, it is unclear if the virus is spread through other bodily fluids, such as tears. Today's just-published study ...

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Eye

Eyes are organs that detect light, and send signals along the optic nerve to the visual and other areas of the brain[citation needed]. Complex optical systems with resolving power have come in ten fundamentally different forms, and 96% of animal species possess a complex optical system. Image-resolving eyes are present in cnidaria, molluscs, chordates, annelids and arthropods.

The simplest "eyes", such as those in unicellular organisms, do nothing but detect whether the surroundings are light or dark, which is sufficient for the entrainment of circadian rhythms. From more complex eyes, retinal photosensitive ganglion cells send signals along the retinohypothalamic tract to the suprachiasmatic nuclei to effect circadian adjustment.

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