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31 Cards in this Set
- Front
- Back
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What is deerebrate rigidity posturing? |
A postural change that occurs in some comatose patients |
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What is coma? |
Totally unaware of anything -absence of any cerebrally mediated motor response to noxious stimuli |
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Three common causes of coma? |
Dysfunction of damage of the Cerebral cortex Reticular formation -nuclei of reticular formation damaged not ascending pathways Thalamus- so cortex can't receive input |
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What are other functions that can cause coma's? |
Metabolic (toxic) -Liver failure (liver doesn't detoxify chemicals in the body anymore, so toxins build up which are toxic to neurons and shut down normal cellular function) -Renal failure (can do same thing as above) |
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When is a clinical drug induced coma administered? |
Done to minimize bleeding |
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What is the Glasgow coma score? |
Scored between 3=worst and 15=best -4 points based on eye movement -5 points based on verbal response -6 points based on best motor response (add the scores from the three categories) |
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What is the definition of brain death? |
Irreversible loss of clinical function of the whole brain, including the brainstem |
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What are the 3 cardinal signs of brain death? |
Coma-cerebral unresponsivity Absence of brainstem reflexes-cardiovascular reflexes, gag reflex... Apnea-absence of spontaneous respiration |
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What does an EEG measure? |
Electrical activity of the brain (the summed post synaptic potentials) |
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What are the characteristics of an EEG? |
Frequency (2-20 Hz)-number of oscillations per second Amplitude (20-100mV)-the ups and downs |
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What do the Rhythm generators in the thalamus control? |
The frequency/ oscillations per second |
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What is normal sleep? |
An altered state of consciousness others=hypnotic state, delirium |
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What is the circadian rhythm? |
Biologic clock that cycles everything for 24 hour periods, -natural physiological processes that vary throughout the day |
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What are types of activites under circadian rhythm |
HR BP Sleep Digestion Hormones... |
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What nucleus is in charge of maintaining the circadian rhythms? |
Suprachiasmatic nucleus -contains retinal cells and is sensitive to light |
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What part of the brain is the suprachiasmatic nucleus located? |
hypothalamus (supraoptic region above the optic chiasm) |
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How is sleep affected by the suprachiasmatic nucleus? |
It is influenced by but not controlled by it |
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What special sense is closely linked to the suprachiasmatic nucleus? |
Vision -receives retinal input from eyes some of the neurons from the optic pathway are siphoned off and synapse with suprachiasmatic nucleus and cause up or down regulation of genes which produce proteins and the cells produced then project to and influence other parts of body |
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Where is the sleep center of the pons located? |
Reticular formation of the pons -inhibitory in nature so it shuts down the reticular formation and puts us to sleep |
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What two areas are in a constant battle for your state of consciousness? |
ARAS and sleep center of the pons ARAS=excitatory (if wins then you are alert) sleep center=inhibitory |
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What aspects of sleep indicate that it is an active process? |
-No general inhibition of neural activity (brain still working very hard) -Blood flow and O2 demand do not decrease |
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What are the 3 major sleep-wakefulness stages? |
Waking stage Slow wave sleep (non-REM sleep) REM sleep |
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What are the 3 stages of the waking stage? |
alert wakefulness (Beta rhythm >13) relaxed wakefulness (Alpha rhythem (8-13)) relaxed drowsiness (Decrease in alpha (closer to 8)) |
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How do you enter slow-wave sleep? |
You enter from one of the stages of wakefulness |
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What are the characteristics of slow-wave sleep? |
There are no dreams Primarily used for rest MM tension is reduced but not eliminated Movement is minimal but possible |
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How many stages are in slow-wave sleep? |
4 stages, it takes 45 minutes to cycle through them Then you cycle backwards through them and that's another 45 minutes -you decrease frequency and increase amplitude as you go through the stages |
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What are the different EEG frequencies/rhythms? |
(BAT-D) Beta- >13 Hz Alpha- 13-8 Hz Theta- 8-4 Hz Delta- 2 Hz |
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Describe the four stages of slow-wave sleep? |
Stage 1- light sleep, easily aroused by mod stimuli (alpha-rhythm transitions to theta rhythm (8-4 Hz)) Stage 2-Further lack of sensitivity to activation and arousal-predominantly theta rhythm Stage 3-Deep sleep -theta transitions to delta Stage 4-deep deep sleep - delta rhythm (2Hz) |
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When does REM sleep occur? |
After one complete cycle of slow-wave sleep (takes about 90 minutes) |
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How long does REM last? |
About 20 minutes gets longer as the night progresses -paradox because EEG resembles that of a person who is awake, oxygen use is higher than when you are awake |
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How is REM the deepest state of sleep and also the lightest state of sleep? |
Deepest-bc it requires the greatest external arousability Lightest-based on internal arousability |
