Jessica L. Gillette
December 7, 2010
Homeostasis and Sleep
According to Krogh (2009), homeostasis is the maintenence of a relatively normal internal environment. This means that the body has many systems in place to regulate what happens in our bodies to keep it functioning properly. There are very few functions that we have control over in the homeostatic processes' of our bodies. Sleep is one of them. Sleep is very important to the regulation of the body's functions. Sleep is regulated by circadian rhythms. The circadian rhythm is controlled in the brain by an area called the suprachiasmatic nucleus which controlls around 20,000 neurons. These rhythms determine the ideal times for structured and restorative sleep and are generlly in 24 hour cycles. The exact functions of sleep are not exactly known however, those who are sleep deprived have been found to have weakened immune systems and poor brain function. According to the National Institute of Neurological Disorders and Stroke (2007), sleep gives neurons used while we are awake time to repair and that without this shutdown time they become depleted of energy and begin to malfunction. Sleep is also believed to give the brain a chance to exercise important connections that might otherwise deteriorate due to inactivity. The way the body tells us we need to sleep is by the firing off of neurons from the suprachiasmatic nucleus in the brain. The suprachiasmatic nucleus controls the sleep/wake cycle, body temperature, urine production, hormone secretion and blood pressure changes.
Neurotransmitters signal whether we are awake of asleep by acting on different groups of neurons in the brain. Neurons in the brainstem produce seretonin and norepinephrine which are used to keep the brain active when awake. When the chemical adenosine and melatonin builds up in the blood while we are awake it cause us to become drowsy. This sends the neurons in the base of the brain a message that we are...
References: Krogh, D. (2009). Biology: a guide to the natural world, 4th ed. San Francisco, CA: Pearson Education, Inc. Chap. 26 pg. 530
National Institute of Neurological Disorders and Stroke. (May 2007). Retrieved December 8, 2010, from
National Sleep Foundation. (2010). Retrieved December 8, 2010, from
Please join StudyMode to read the full document