Altered States of Awareness Flashcards
State of awareness
The sensations, perceptions, cognitions and emotions we experience.
Circadian rhythm + Examples
A behavioural or physiological cycle that occurs over a 24 hour period.
Example:
- Alertness
- Sleep/wake cycle
- Body temperature
- Blood pressure
What are circadian rhythms controlled by?
- Exogenous rhythms (external)
- Endogenous rhythms (internal)
Exogenous rhythms
External cues including lifestyle and environmental factors (showering before bed, dressing each morning).
Endogenous rhythms
Biological processes which are influenced by the hypothalamus part of the brain (SCN = suprachiasmatic nucleus).
Suprachiasmatic nucleus (SCN)
Located in the hypothalamus in the brain, the suprachiasmatic nucleus acts a biological clock and controls the sleep/wake circadian rhythm.
How is the sleep/wake cycle controlled (SCN)?
- Light entering the eyes falls on the retina and a signal is sent via the optic nerve to the SCN.
- The SCN delivers a message to the pineal gland which secretes the hormone melatonin.
- The release of melatonin increases when it is dark and decreases when it is light.
- Increased melatonin makes people sleepy and inversely, reduced melatonin makes people more alert.
What are the needs for sleep?
- Energy conservation: During sleep less energy is used and energy is conserved due to lower metabolic rate and lower temperature.
- Repair and restoration: Sleep aids repair and restoration as cells are repaired, the immune system is strengthened and waste products from muscles are eliminated.
- Memory consolidation: Learning is consolidated during sleep, with memories being stored logically so they are accessible later.
Sleep dept
An accumulation of the difference between the amount of sleep that a person requires to function at an optimal level and the amount they actually have.
Sleep deprivation
Occurs when we don’t have enough sleep to operate at an optimal level.
What are the effects of sleep deprivation?
Common symptoms:
- daytime sleepiness
- moodiness
- slowed reaction time
- poorer memory
- hand tremors
- micro sleeps
Long-term effects:
- health problems due to reduced immune system
- hallucinations
- delusions
Microsleep + two situations when particularly dangerous
A brief unintended loss of attention, which often occurs when a tired person is performing a monotonous task.
- Driving
- Operating Machinery
Does sleep debt build up?
No sleep debt does not continue to build up. If we have 8 hours too little sleep over a long weekend, 8 hours sleep is not required to recover. Only about 3 hours extra the next night and 2 hours extra the second night would return us to normal.
Stages of sleep
During sleep a person moves up and down through 5 different stages of sleep. Each cycle is 90 minutes and 4 - 5 cycles occur per night.
- Non-REM sleep: A collective term for stages 1 to 4 of sleep
- REM sleep: The fifth stage of sleep which is distinguished by rapid eye movements.
Method of investigating sleep: Electro-Encephalographs (EEG)
An Electro-Encephalograph is a device which monitors the electrical activity in the brain through the use of electrodes on the scalp to measure electricity produced by neurons in the brain. The different stages of sleep produce different traces of electrical activity called brainwaves. The height of a wave is called amplitude and the number of wave cycles per second is called frequency.
Sleep disorders
Sleep problems that disrupt the normal NREM-REM sleep cycle, including the onset of sleep. Sleep disorders can cause personal distress and often interfere with an individuals normal functioning.
Sleep apnea (biological level)
A sleep disorder in which a persons breathing stops periodically for a few moments while they are asleep.
Problems associated with sleep apnea
Due to consistent waking up, person is prevented from completing full cycles of sleep and remain until the light stage. Therefore the person fails to achieve the sleep needs.
This leads to:
- Sleep deprivation
- High blood pressure
- Heart problems
Two types of sleep apnea
- Obstructive sleep apnea
- Central sleep apnea
Obstructive sleep apnea
An obstruction in the throat during sleep, due to the complete relaxation of the throats muscles causing blockage of the upper airway at the back of the tongue.
This can be a result of several factors: being overweight and drinking alcohol before sleep. It is more common in overweight men over 40.
Central sleep apnea
This type is cause by a delay in the signal from the brain to breathe.
Treatment for sleep apnea
Mild sleep apnea: behavioural changes (loosing weight and refraining from sleeping on back)
Moderate-high sleep apnea: a CPAP machine
C-PAP (continuous positive airway pressure)
A C-PAP is a machine that blows air into the nose via a nose mask, keeping the airway open and unobstructed.
Narcolepsy
A sleep disorder in which people experience irresistible and unpredictable daytime attacks of sleepiness, lasting 5 to 30 minutes. Sleep attacks commonly occur at times when people are in a heightened state of alertness.
Problems associated with narcolepsy
- Sleep attacks
- Loss of muscle tension
- Hallucinations may be experienced as the person goes in to REM almost immediately.