Download Understanding the Role of the Reticular Activating System in Sleep and Wakefulness and more Slides Neurology in PDF only on Docsity! Sleep Docsity.com RAS excitatory area located in the reticular substance of the upper mid-pons and mesencephalon Inhibitory reticuler area located in the reticular substance of the lower mid-pons and medulla Docsity.com RAS cutting the brain stem above the point where the fifth cerebral nerves enter the pons remove the sensory signals from face and periphery lead to loss of excitation leading to coma cutting the brain stem below the point where the fifth cerebral nerves enter the pons remove the sensory signals from periphery but keep those from the face so keep excitation and wakefulness. cutting the brain stem below the point where the fifth cerebral nerves enter the pons but above inhibitory reticular area lead to wakefulness and loss of sleep. Docsity.com RAS Inhibitory reticuler area -raphe nuclei -in the lower half of the pons and in the medulla -Nerve fibers from these nuclei spread locally in the brain stem reticular formation, upward into the thalamus, hypothalamus, most areas of the limbic system, and cortex and downward into the spinal cord, terminating in the posterior horns where they can inhibit incoming sensory signals, I -Use serotonin as a neurotransmittor Docsity.com RAS
To diencephalon
and cerebrum
Substantia nigra Mesencephalon
(dopamine)
Gigantocellular
neurons of
reticular formation
(acetylcholine)
*
a To cerebellum
Nd
Pons
Locus ceruleus
(norepinephrine)
Medulla
Nuclei of the raphe
(serotonin)
To cord
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Sleep slow-wave sleep -Most sleep during each night (75%) -restful -decrease in many vegetative functions of the body (decreased peripheral vascular tone, BP, Pulse, respiratory rate and basal metabolic rate). - dreams occur but not remembered Docsity.com Sleep REM sleep -rapid movements of the eyes. -bouts lasting 5 to 30 minutes every 90 minutes -dreaming which is remembered. -difficult to arouse by sensory stimuli than during deep slow- wave sleep - depressed Muscle tone with irregular muscle movements - brain metabolism increased Docsity.com Sleep Theories of Sleep passive theory of sleep: excitatory areas of (RAS) in the upper brain stem fatigued and became inactive. active inhibitory process: Stimulation of center located below the midpontile level of the brain stem inhibiting excitatory areas of (RAS) in the upper brain stem leading to sleep. Docsity.com EEG and brain waves EEG: recordings of the electrical activity in the brain from the surface. Electrical activity is the action potentials of large number of neurons which fire synchronously. Waves: these electrical activity is manifested by waves which differ in intensity, frequency and pattern. Docsity.com EEG and brain waves
Alpha WMV
Beta vey Wal NYA Ay
Theta “Wye Ly iy
50 uw
Delta Tl Nee en ee aoe
1 sec
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EEG and brain waves Alpha waves - occur at frequencies between 8 and 13 cycles per second - normal adult people when they are awake and relaxed. Beta waves -occur at frequencies greater than 14 cycles per second -present 1.during specific activation of parts of the brain like intense mental activity 2. REM sleep. Docsity.com
