Answer to Question 1
ANS: B
In Stage 2 (N2), eye movement ceases; brain waves become even slower with the exception of an occasional burst or more rapid brain waves. Pulse rate and respirations slow and body temperature decreases as the individual moves toward deeper stages of sleep. Stage 3 (N3) and Stage 4 (N4) are the periods of deep sleep.
Answer to Question 2
ANS: A
A rise in the hormone melatonin at the onset of sleep helps to promote and maintain sleep, and a drop in levels leads to eventual awakening. The immune system is enhanced as well during sleep as proteins associated with fighting illness are produced. The circadian rhythm, or the typical 24 hour (more or less) cycle through which the body passes, including both awake and sleep cycles, is responsible for regulating all of the physiologic processes in the body. An adequate amount and quality of sleep, therefore, is essential to all of the regulatory mechanisms that take place in the body.