Consciousness and Sleeping Brain - Introduction to Human Physiology - Lecture Slides, Slides of Human Physiology

Download Consciousness and Sleeping Brain - Introduction to Human Physiology - Lecture Slides and more Slides Human Physiology in PDF only on Docsity! Consciousness and the Sleeping Brain • Consciousness is a person’s subjective awareness of both their inner thinking and feeling and their external environment • The five stages of sleep were determined by use of an electroencephalogram (EEG), which records a real-time graph of a person’s cortical electrical activity in the brain – As we slip into sleep and pass through the first four stages, our brain waves change, in general becoming progressively slower, larger, and more irregular, especially in Stages 3 and 4 Docsity.com Five Stages of Sleep • Stage 1: Lasts about 5 minutes • Stage 2: Lasts about 20 minutes – Characterized by sleep spindles, rapid bursts of mental activity • Stage 3: Also known as transitional sleep and is characterized by delta waves, which are large, slow waves • Stage 4: Lasts about 30 minutes – Parasympathetic nervous system is active, as muscles relax, heartbeat slows, blood pressure declines, and digestion speeds up Docsity.com Five Stages of Sleep • These 5 stages (the sleep cycle) repeat themselves about every 90 minutes, with Stages 3 and 4 getting shorter with each cycle, and REM and Stage 2 getting longer with each cycle • REM sleep rebound effect is a significant increase in the proportion of REM sleep following deprivation of REM sleep Docsity.com Why do we sleep and dream? • Sleep deprivation results in: – Impaired concentration and a general bodily feeling of weakness and discomfort – Suppression of the immune system, lessening one’s ability to fight off infection and disease – Increased vulnerability to accidents – Increased difficulty in concentrating, studying, and taking exams Docsity.com Why do we sleep and dream? • Explanations for dreaming : – Sigmund Freud proposed that dreams were disguised outlets for inner conflicts of our unconscious mind, a view not accepted by modern sleep researchers – The activation-synthesis hypothesis contends that dreams are merely the sleeping brain’s attempt to make sense of random neural activity without the rational interpretation of the frontal lobe Docsity.com