PIC PIC 007
Monday 6 January 2014
the eyes
Eyes are the organs of vision. They detect light and convert it into electro-chemical impulses in neurons. The simplest photoreceptor cells in conscious vision connect light to movement. In higher organisms the eye is a complex optical system which collects light from the surrounding environment, regulates its intensity through a diaphragm, focuses it through an adjustable assembly of lenses to form an image, converts this image into a set of electrical signals, and transmits these signals to the brain through complex neural pathways that connect the eye via the optic nerve to the visual cortex and other areas of the brain. Eyes 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 molluscs, chordates and arthropods.The simplest "eyes", such as those in microorganisms, 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.
marine corps recruit Training's
One of Marine Corps Recruit Training’s most recognized challenges is pugil stick training. The pugil sticks are designed to represent a bayoneted rifle and the training simulates a close encounter with an enemy.
american army
A Marine with Delta Company, 1st Light Armored Reconnaissance Battalion, fires an AT-4 light anti-armor weapon as part of a week-long training exercise at Army base Fort Irwin in California.
free syrian army
violence killed his brother
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