Jackie Miranda
ENGL 20003
Jeff Brewer
03/08/2015
Informative Paper: Several Stages of Sleep

Sleep is not the time where your body and brain just shut off, while people are resting, their brains are staying busy. The body does many things while we sleep. According to Smith (2015), our metabolism generally slows down during sleep, but all major organs and regulatory systems continue to function. We have all experienced not wanting to get up in the morning, many people feel sleepy or “zone out” on a daily basis. These types of feelings bring up the importance of sleep and the powerful need for sleep. In fact, there are two types of sleep: rapid eye movement (REM) and non-REM (NREM) sleep. Neurotransmitters are nerve signaling transmitters that control whether we are asleep or awake, which act on different group of neurons in the brain. Neurons in the brainstem, which connects the brain with the spinal cord, produce neurotransmitters such as serotonin and norepinephrine. Both serotonin and norepinephrine are neurotransmitters that allow some parts of the brain to function while we are awake. Other neurons at the base of the brain begin signaling when we are falling asleep. A chemical called adenosine starts building up in our blood while we are awake and causes sleepiness, or drowsiness. This chemical slowly breaks down while we sleep. Sleep develops through recurring sleep stages that are very different from one another. Both deep sleep and dreaming sleep are vital for your body and mind. Each kind of sleep plays a huge role when preparing your body for the day ahead. The two main types of sleep are non-REM sleep and REM sleep. Non-REM sleep contains of four stages of sleep, each becoming deeper than the previous stage. “As sleep gets deeper, the brain waves become slower and have greater amplitude, breathing and heart rate slow down, and blood pressure drops” (Sleep Foundation, 2006, p. 5) Stage one is when you become drowsy, a transition from being awake to falling asleep. Brain waves and muscle activity start slowing down during this stage, some people may even experience muscle jerks, following with a falling sensation. Stage two is the light sleep period, in which eye movements stop. The brain waves become slower, and muscles begin to relax. Our heart rate slows down, and our body temperature decreases. Transitioning from stage two to stages three and four (slow wave sleep), slow brain waves and smaller rapid waves occur. Our blood pressure drops even more and our body temperature drops even lower, with the body becoming immobile. In stages three and four eye movement is no longer occurring, and activity in muscles is decreased. According to Lawrence Robinson (2015), it is extremely difficult to be awaken during this stage, “if you are awakened, you do not adjust immediately and feel groggy and disoriented for several minutes.” REM sleep, also known as “dream sleep,” occurs about seventy to ninety minutes after falling asleep. In an article called “Brain Basics: Understanding Sleep,” the National Institute of Neurological Disorders and Stroke states that, “When we switch into REM sleep, our breathing becomes more rapid, irregular, and shallow, our eyes jerk rapidly in various directions, and our limb muscles become temporarily paralyzed.” Also, during REM sleep our heart rate increases and blood pressure rises, and penile erections develop in males. Most dreams occur during REM sleep, when we awake from REM sleep, we are often able to describe illogical