AP PSYCHOLOGY

Detailed explanation-1: -Crucial evidence indicates that orexin-A increases food intake by delaying the onset of a behaviourally normal satiety sequence.

Detailed explanation-2: -Considered together, these behavioral and physiological effects suggest that the orexin neuropeptides coordinate many aspects of arousal. Orexins promote and stabilize wakefulness, inhibit and regulate REM sleep, and increase locomotion and sympathetic tone.

Detailed explanation-3: -Orexin receptor antagonists are a novel class of sedative-hypnotics for sleep-onset and sleep-maintenance insomnia, and currently three agents have been approved by the FDA. Most adults need about 7 to 9 hours of sleep per day.

Detailed explanation-4: -Orexin deficiency causes abnormalities in energy homeostasis, stress-related behavior, and reward systems. Orexin excites waking-active monoaminergic and cholinergic neurons in the hypothalamus and brain stem regions to maintain a long, consolidated waking period.