Importance of sleep Flashcards
Define sleep.
A naturally occurring ASC that features the suspension of awareness of the external environment and physiological changes to the body.
What are the four physiological methods of measuring sleep?
Electroencephalograph (EEG). Records brainwave activity.
Electromyograph (EMG). Records the electrical activity of muscles involved in voluntary movement.
Electrouloorograph (EOG). Records electrical activity of muscles involved in eye movement.
Electrocardiograph (ECG). Records electrical activity of heart muscles.
Define ultradian rhythms.
A biological rhythm shorter then 24 hours.
Outline the different stages of sleep.
NREM stage 1, NREM stage 2, NREM stage 3, NREM stage 4. REM.
Define hypnogogic jerks.
Muscles twitches causing us to jolt. Occur in NREM stage 1 as we are falling asleep.
Why is REM sleep referred to as paradoxical sleep?
Because our body is in its most relaxed state, but our mind is in its most active state.
Define the sleep/ wake cycle.
A roughly 24 hour circadian rhythm determined by our hypothalamus (internal body clock).
Define the evolutionary theory of sleep.
We have periods of inactivity (sleep) when we do not need to engage in activates important to our survival. Under this theory we sleep as it expends less energy and because it protects us from attack as we are not gaining the attention or predators.
Define the restorative theory of sleep.
Sleep provides us an opportunity for the body to repair and rejuvenate itself. Sleep keeps the mind and body functioning at an optimal level by replenishing the resources the body used from the previous day. NREM repairs muscle and tissue damage, REM restores mental processes.
Outline reasons to support and criticisms against the evolutionary theory of sleep.
Support: animals with fever physical needs sleep for longer then animals with more physical needs.
Criticism: It makes more sense for animals to be awake and aware of danger as long as possible, so why evolve to be unaware in sleep?
Outline reasons to support and criticisms against the restorative theory of sleep.
Support: we feel tired when we go to sleep and refreshed when we awake, this would indicate some revitalisation from sleep.
Also people who suffer from sleep deprivation are more susceptible to illness, showing they are missing something they would have had from sleep.
Criticism: when we sleep the brain is still active via dreams so its not actually conserving energy. Also people who have no physical activity get the same amount of NREM sleep as people who have had physical activity, what are they then restoring?
What is the role of melatonin in sleep?
The most common sleep hormone. It is released from the pineal gland when there is no light (via the suprachiasmatic nucleus) and produces a feeling of sleepiness.
Define endogenous.
Based on internal factors.
Define zeitgeners.
External factors that influence the sleep/ wake cycle. Eg the detection of light.
What are the differences in sleep across the lifespan?
The amount of total sleep needed decreases as age increases as it relative to hormone production.
The distribution of time spent in REM/NREM sleep decreases from a 50/50 split for babies to 15/85 for elders showing a decrease in the amount of time spent in REM sleep over age.
