Sleep :: Biology Essays Research Papers

Sleep Sleep is my favorite thing in life. My first waking thought is usually "when will I be able to sleep again?" But why do I love to sleep? What goes on behind my closed eyelids and what does sleep do for me? As early as 350 BC, Aristotle pondered the state of sleep: "With regard to sleep and waking, we must consider what they are: whether they are peculiar to soul or to body, or common to both." Researchers are still engaged in investigating the complexities of sleep. To answers these questions, I turned to the Internet for help. After an exhausting search, weeding through web pages designed for the average insomniac looking for a quick fix to his/her troubles, and technical research papers discussing the specifics of neurobiological functions, I found some helpful writings. What is known is that sleep is founded on patterns of bodily functions and brain activity. While we are asleep, our brains exhibit distinct and separate stages of activity. This paper will discuss the basic pattern s and stages of sleep within humans and the functions of each stage. This introduction to sleep will serve as the basis for further research later in the semester. Sleep follows distinct patterns throughout the day. Circadian rhythms are daily cycles of biological activity which mediate many of our metabolic functions. Blood pressure, heart rate, body temperature and hormonal secretions ebb and flow throughout the day in a cyclic pattern, often referred to as the "biological clock". These rhythms are controlled by the superchaismatic nucleus region of the hypothalamus, which relies on both internal timing mechanisms within specific neurons as well as outside influences to set this clock. The biological clock is kept running by "zeitbergers", that is, any input to the brain such as daylight, the smell of food, or temperature change. Sleep cycles follow our circadian rhythms. It has been found that the natural hormone melatonin plays a large part in mediating sleep. As darkness falls, enzymes in the brain stimulate the release of melatonin from the pineal gland in the brain. Melatonin induces sleep by influencing the superchiasmatic nucleus. The release of melatonin is halted when daylight arrives, and we experience wakefulness. Other mediators such as seratonin, prolactin and prostaglandin have also been linked to the sleep cycle, but their exact role is unclear. Upon falling asleep, the brain and body go through five stages of sleep in one sleep cycle.