The nature of sleep has always interested people. Scientists for centuries have tried to study the causes and understand the mechanisms of dreams, sometimes offering fantastic theories. For example, more than a hundred years ago, this human condition was considered poisoning - supposedly during the period of wakefulness, poisons accumulate in the body. Today much more is known about this complex phenomenon, but not all questions are yet fully answered.
Instructions
Step 1
Sleep is a physiological phenomenon inherent in many living things (fish, mammals, birds, some insects), during which brain and motor activity is reduced, the reaction to external stimuli slows down. The first scientific explanation of the nature and causes of sleep was given by the Soviet physiologist Pavlov, who established that in the process of any work, the cells of the cerebral cortex get tired, and inhibition begins, which protects them from exhaustion. When it spreads to other areas, sleep occurs, during which the cells rest.
Step 2
Until the exact purpose of sleep has been established, many other theories and hypotheses have emerged. For example, some scientists believe that this state is necessary for the brain to process the information received during the day. It is also believed that the sleeping brain evaluates the physical condition of the body and develops a program to maintain the parameters of the body. Sleep is known to help restore immunity.
Step 3
The physiology of sleep has been studied in more detail. In a state of sleep in the body, the activity of catabolic processes decreases, and anabolism increases. In all animals, including humans, these are cyclical processes called circadian rhythms. One of the most important factors in the onset of sleep is the level of light, which affects the concentration of phyto-dependent proteins. Before falling asleep, the following processes are observed in a person: a state of drowsiness begins, which is characterized by a decrease in the activity of the brain, the level of consciousness, the sensitivity of the sensory systems gradually decreases, the heart begins to beat less often, the secretory activity of the glands decreases.
Step 4
Sleep consists of two main phases - slow and fast, which replace each other in cycles. About five such cycles usually take place in one night. When falling asleep, a person begins a slow phase, which includes four stages: nap, immersion in sleep, deep sleep and the deepest sleep, in which it is very difficult to wake up the body. With a slow phase, the body temperature drops, the eyeballs move smoothly under the eyelids, breathing and heart rate slow down. At this time, growth hormone is produced, tissues are regenerated. After an hour and a half, a fast phase begins when muscle tone falls, completely immobilizing a person. The temperature rises, the eyes move sharply, the internal organs are actively working in the body. Many dreams can be seen in 15 minutes of REM sleep.
Step 5
The term "sleep" also refers to images that occur in a person in a sleeping state, usually in a fast phase. These are dreams, visual, auditory, tactile and other feelings that resemble objective reality. As a rule, the dreamer does not understand that he is sleeping. Everyone is capable of dreaming, but not everyone remembers them. These processes are believed to be essential to protect against downtime of the endocrine system.
