Sleep: Understanding the Basics
Basics of Sleep IntroductionSleep is defined as a state of unconsciousness from which a person can be aroused. In this state, the brain is relatively more responsive to internal stimuli than external stimuli. Sleep should be distinguished from coma. Coma is an unconscious state from which a person cannot be aroused. Sleep is essential for the normal, healthy functioning of the human body. It is a complicated physiological phenomenon that scientists do not fully understand. Historically, sleep was thought to be a passive state. However, sleep is now known to be a dynamic process, and our brains are active during sleep. Sleep affects our physical and mental health, and is essential for the normal functioning of all the systems of our body, including the immune system. The effect of sleep on the immune system affects one’s ability to fight disease and endure sickness. States of brain activity during sleep and wakefulness result from different activating and inhibiting forces that are generated within the brain. Neurotransmitters (chemicals involved in nerve signaling) control whether one is asleep or awake by acting on nerve cells (neurons) in different parts of the brain. Neurons located in the brainstem actively cause sleep by inhibiting other parts of the brain that keep a person awake.Next: Importance of Sleep » Viewer Comments & ReviewsSleep - Problems ExperiencedThe eMedicineHealth physician editors ask:
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Electroencephalography (EEG) »
Electroencephalography (EEG) Introduction
The electroencephalogram (EEG) is a measure of brain waves. It is a readily available test that provides evidence of how the brain functions over time.
- The EEG is used in the evaluation of brain disorders. Most commonly it is used to show the type and location of the activity in the brain during a seizure. It also is used to evaluate people who are having problems associated with brain function. These problems might include confusion, coma, tumors, long-term difficulties with thinking or memory, or weakening of specific parts of the body (such as weakness associated with a stroke).
- An EEG is also used to determine brain death. It may be used to prove that someone on life-support equipment has no chance of recovery.
- Scientists first captured and recorded brain waves in dogs in 1912. By the 1950s the EEG was used commonly throughout the United States.
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Sleep Disorder: Problems Associated with Other Disorders »
Sleep disturbances in youth represent highly common phenomena that, in severe forms, can interfere with daily patient and family functioning.
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