One of the most unique adaptive reactions of our body is the sleep. Sleep is a circadian biorhythm of reduced brain activity that provides rest for the body. The newborn sleeps about 20 hours a day. The need for sleep decreases over the years. Now for adults its duration is 7-8 hours. There are three types of sleep: natural, artificial (narcotic or hypnotic) and pathological, which is possible with anemia of the brain, damage to its structures or lethargy.
Natural daily sleep consists of two phases: slow (orthodox) and fast (paradoxical), which alternate with each other.Dreams with images of objects or appearance are found in both phases of sleep and all people see them 4-6 times a night. If awakening occurs in the stage of paradoxical sleep, a person remembers his dream in detail. When he wakes up in the stage of orthodox, a man often remembers nothing. But in the slow phase the short-term memory information is transferred to the long-term one. Therefore, learning a new study material before bedtime contributes to its better memorization. Also there are several theories of sleep.
The first theory is humoral, according to it sleep occurs due to peptides acting on the brain. And the second one is nervous theory, which includes the theory of inhibition of the cortex, proposed by Pavlov, and the theory of the sleep center, in which the main role is played by the nuclei of the hypothalamus, the excitement of which makes a person fall asleep. Despite this, sleep is still one of the most interesting mystery for scientists.
DISCUSSION:
Tell me about your or your friend's dreams.