Introduction:
Sleep is an unavoidable part of a person’s daily routine. Sleep helps in energizing the body by improving the immune system. Sleep enables the body to take rest and regain the energy that was utilized during day time. Getting an adequate amount of sleep is necessary for the efficient functioning of the body. Lack of adequate sleep may affect parts of the brain leading to a lack of concentration and poor memory.
What Is Sleep?
Sleep is a complicated biological process that helps in re-energizing, processing new information, and staying healthy. Even though the body is resting during sleep, some parts of the brain remain active. Sleep is necessary to maintain various brain functions, like the communication of neurons (nerve cells) with each other. Inadequate sleep can affect a large number of organs in the body and raises the risk for conditions like diabetes, obesity, heart disease, depression, and high blood pressure.
What Are the Factors That Regulate Sleep?
According to researchers, two main factors regulate sleep. They are as follows:
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Circadian Rhythms: These are mental, behavioral, and physical changes that undergo in the body of a living organism in the twenty-four hours cycle. These are controlled by a small region present in the middle of the brain and are affected by changes in the environment, like light and darkness. Specialized cells present in the retina of the eyes process light and make the brain aware of day and night. Hence, it is responsible for the act of sleeping at night (dark) and waking up during the daytime (light).
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Sleep Drive: This is the urge demanded by a person’s body to sleep, which is similar to the urge to eat when a person feels hungry. If a person feels exhausted, his body forces him to fall asleep. Even if the person controls or prolongs it, after a certain point, the person is driven to fall asleep. In case the person is not able to fall asleep due to any reason, the body has the power to engage in microsleep with eyes open, which lasts for just a few seconds.
What Happens In The Brain During Sleep?
Some structures of the brain are involved in the process of sleep. They are as follows:
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Hypothalamus: Hypothalamus is a pea-nut-sized structure that is located deep inside the brain. The hypothalamus contains a network of nerve cells that function as centers for controlling sleep and arousal. The hypothalamus contains a structure, namely the suprachiasmatic nucleus (SCN), that contains several cells collecting information from the eyes when exposed to light, thereby regulating the body to sleep during the night and stay awake during the day time. Any damage to the suprachiasmatic nucleus makes the person sleep throughout the day time as the person’s body is unable to regulate sleep based on the light-dark cycle.
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Thalamus: The thalamus is an egg-shaped structure located in the center of the brain. The thalamus acts as a relay station since all the information initially reaches the thalamus before being directed to the cerebral cortex (the outermost layer covering the brain). The cerebral cortex helps in the interpretation and processing of information. During a major part of the sleep cycle, the thalamus tunes the body out of the external world. However, the thalamus is active during the period just after the person has fallen asleep, which may last from one hour to one and a half hours. During this time, the thalamus sends sounds, images, and other sensations that are responsible for a person’s dreams.
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Brain Stem: The brainstem is the stalk-like region present at the bottom of the brain that links the brain with the spinal cord. The brainstem helps in managing the transitions between sleep and wakefulness by communicating with the hypothalamus. The brainstem helps in sending signals to stop the activity of muscles that are responsible for limb movements and body posture. These signals are sent during the first few hours after the person has fallen asleep. The signals help a person not to translate his dreams into action during sleep. The sleep-stimulating cells present within the brainstem and hypothalamus help in decreasing the activity of arousal (transition from deep sleep to light sleep or partial wakefulness) centers by producing a brain chemical called gamma-aminobutyric acid (GABA).
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Pineal Gland: The pineal gland is a tiny endocrine gland (a structure that produces substances like hormones and releases them straight into the bloodstream) located in the center of the brain. The pineal gland obtains signals from the suprachiasmatic nucleus and increases the secretion of a hormone called melatonin that regulates sleep when the lights go down. Blind people who are unable to coordinate the natural sleep-wake cycle with the help of natural light can balance their sleep cycles by using small quantities of melatonin.
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Forebrain and Midbrain: The brain is divided into three parts called forebrain, midbrain, and hindbrain. The forebrain is the largest part of the brain and is covered by a layer called the cerebral cortex. The midbrain is the topmost portion of the brain stem and helps in processing auditory and visual signals. The basal forebrain (a region near the bottom and front of the brain) helps in promoting sleep and supports the sleep drive by the secretion of a chemical by-product called adenosine. The midbrain contributes a role in the arousal system (transition from the state of deep sleep to light sleep or wakefulness).
Conclusion:
Sleep plays a major role in the efficient functioning of the brain. Sleep helps in the removal of waste products from the brain cells, which cannot take place when a person is awake. Lack of sleep can lead to problems affecting concentration and thinking capacity. Reduced sleep affects the ability of the nervous system to transform its activity according to various stimuli by reframing its structure and function. Sleep deprivation weakens the immune system in the body, which increases the likelihood of infections and illness. Hence, getting the right amount of quality sleep by following good sleep habits should become a part of the daily routine of life, following a few simple steps like going to sleep and getting up around the same time each day, creating a good sleep environment by turning down the lights, staying active during the day time, avoiding loud noises during sleep time, and taking showers in warm water before sleep helps in getting a night of good sleep. Experiencing any trouble with sleeping during the night time or feeling drowsy during the daytime without any particular reason should be taken care of by consulting a doctor.
