Choose a popular leadership model and a biblical leader and then describe how the model is demonstrated in the biblical leader’s style and approach.
Discussion question 2:
From your reading, what constitutes a good leader? In what ways have you experienced a good leader?
In contrast to anaesthesia, thermoregulation is maintained during sleep. However, the shivering threshold is decreased and body core temperature decreases by about 0.5°C in humans and 2°C in hibernating mammals. Body temperature is linked to the circadian rhythm and reaches its nadir at about 3 am. Thermoregulation is quite good in human infants compared with other species. Control of sleep Sleep follows a circadian (~1 day) cycle, the periodicity of which is regulated by an independent genetically determined ‘intrinsic clock’ which is entrained to a 24 h cycle by external cues (Zeitgebers) such as light, darkness, clock time, working patterns and meal times. When a human being is deprived of all external time clues and is exposed to constant levels of illumination (‘free running’), the wake/sleep cycle typically lengthens to about 24.5 h. Subjects who are born blind without any appreciation of light generally free run while those blinded in later lifeor who retain some perception of light remain entrained. All living organisms, including plants and fungi, have been found to have clock genes and to show an inactivity/activity cycle. In mammals, control of the intrinsic clock is located in the SCN on either side of the third ventricle, just above the optical chiasm. In animal experiments, its destruction leads to a change from the normal sleep cycle into several shorter sleep/activity periods during the day. As noted above, melatonin secretion is prompted by the SCN just before the usual time of sleep onset. A mismatch of this pattern with sleeping time, as occurs in shift workers and after trans-meridian flights, leads to sleep disturbance (‘jet lag’) as the subject is trying to sleep during their circadian day. Light therapy can be helpful in re-setting the circadian clock and the interested reader is referred to the bibliography. The propensity to fall asleep varies throughout the day and depends upon both circadian factors (process C) and time since the last sleep period (process S). The longer the time since the last sleep period, the greater will be process S. However, its propensity will be modulated by process C. The circadian pressure to sleep is greatest at ~2 am with a secondary peak at ~2 pm. It is least at ~6 am and ~6 pm. If a subject elects to stay awake throughout the night, they will feel most sleepy in the small hours of the morning but will get a ‘second wind’ as morning approaches and the circadian pressure to sleep declines. If wakefulness is maintained, a second period of sleepiness and relative alertness will follow in early afternoon and early evening, respectively. Some of the 8-h sleep debt will be recovered that night but process C will ensure that awakening will occur at or shortly after the normal waking time. Sleep is normally an actively initiated and not a passive process. Unless a subject is sleep deprived, successful initiation of sleep depends both upon the phase of the circadian clock and external factors (recumbent position, darkness, reducing sensory input). Over the years, considerable effort has been focused on a search for: (i) a ‘sleep centre’, a nucleus or region in the brain where stimulation or ablation would lead to sleep; and (ii) a hormone or transmitter which would reliably induce sleep. Neither have been found because the mechanisms resulting in sleep are complex and diffuse. During wakefulness, the CNS is dominated by activity of the ascending reticular activating system (RAS) in the brain stem. This formation receives sensory input from all peripheral sensors and projects to the thalamus and the cortex. Its main neurotransmitters are acetylcholine, noradrenaline, dopamine and histamine which explains the sedative effect of antagonists to these substances. A decrease in its activity permits sleep to be initiated by suppressing incoming external stimuli. The induction of SWS is associated with the secretion of γ-aminobutyric acid (GABA) from basal forebrain neurones. Therefore, it is not surprising that benzodiazepines and barb>GET ANSWER