The vertebrobasilar arteries are the blood vessels in the back of the neck, next to the spinal cord, that supply the brainstem -- the portion of the brain that, among other things, is responsible for maintaining consciousness. A blockage of blood flow in the vertebrobasilar arteries can cause syncope.
1. NREM-a recurring sleep state during which rapid eye movements do not occur and dreaming does not occur; accounts for about 75% of normal sleep time. nonrapid eye movement, nonrapid eye movement sleep, NREM sleep, orthodox sleep. sleep, slumber-a natural and periodic state of rest during which consciousness of the world is suspended; he didn't get enough sleep last night; calm as a child in dreamless slumber. 1  Facebook.
A) Sleep is an unconscious state in which an individual's reaction to environmental stimuli is decreased. B) Most of the sleep cycle is made up of rapid eye movement (REM) sleep. C) An adult has four to six sleep cycles, each with NREM sleep and REM sleep during a normal night's sleep. About every 90 minutes, REM sleep recurs. A) Sleep is an unconscious state in which an individual's reaction to environmental stimuli is decreased.  CORRECT. About every 90 minutes, REM sleep recurs.