Case 1 Sleep is a well known phenomena and requires no introduction as it is known that every individual requires some sleep. During the process of going to sleep an individual goes through several stages. The first stage involves a slight hazy feeling that is easily disrupted by even light noise. In the second stage most physiological activity significantly slows down and the heart beat, breathing and mental activity all reduced slightly. There are two further stages of sleep during which the body experiences even greater changes. The process of sleep involves a cycle through these stages throughout the period of rest (Schenck and Schenck, 2007). Healthy sleep is essential for an individual’s productivity and overall health. However, sleep deprivation is becoming a common problem in society owing to a number of reasons. The inability to fall asleep results in individuals experiencing a number of problems. An occasional lapse is normal but a repeated occurrence of the phenomenon over a period of time should not be left unattended as it could lead to serious problems for the individual (Schenck and Schenck, 2007). The importance of sleep has led to many theories on the functions of sleep in organisms. One such theory, the recuperative theory suggests that sleep is period during which recovery and repair occur. Recent studies on this theory have proposed process involved with immune function or thermoregulation as part of the processes that occur during sleep. One problem with this theory is the fact that REM sleep is not adaptive and temperature control is reduced significantly (Wagner & Silber, 2004). However, there is evidence of a restorative function of SW sleep. It has been noted that people sleep better after exercise and that selective exercises are known to increase SW sleep. Exercise increases the temperature of the brain and thus induces sleep; it has been proven that heating of the temperature of the head even without exercise increases SW sleep. This is probably because the basal areas of the fore brain that control sleep are also involved regulation of temperature (Wagner & Silber, 2004). Another theory that has been proposed in relation to sleep is the Circadian theory which suggests that sleep evolved as a mechanism to fit organisms into the light dark cycle of the world. According to this theory during the periods of darkness and sleep the animals would conserve energy that they will use during periods of light when they are more active. In the case of some species of animals this theory fits much more appropriately than the recuperative theory (Wagner & Silber, 2004). While there is no relationship between body size, activity level and sleep periods are related to the need to obtain nourishment. It has been noted that grazing animals often sleep for shorter periods than hunting animals. Based on the brief information provided on the topic it would appear that the recuperative theory is more justified. It is known that most hunters hunt at night and therefore take advantage of the dark to capture their prey. As opposed to fitting in with the light dark cycle it would appear more logical to assume organisms use sleep as a period to recover from their activities. Case 2 As is the case with most medical disorders the importance