The Physiology of sleep Flashcards
Who discovered normal sleep physiology?
Discovered by Bacon constatatin
Why do our bodies require long hours of sleep?
Restore and rejuvenate,to grow
muscle and repair tissue and synthesise hormones.Memory is formed and the brain
is able to react to events of the previous days.
What is entrainment?
Is the process by which environmental rythms such as the light
dark cycle regulates the period and phase relationship of a sel- sustained oscillator.
What is a circadian slave oscillator?
Can drive a rhythmic output but requires othe
oscillators known as pacemakers- for its entraiment and or its function. A slave oscillator can therefore be self sutained but cannot operate properly independently of ther oscillators.
What is the difference between a circadian slave oscillator and a pacemaker?
Is a specialised oscillator that operates independently of other oscillators to drive rhythmic outputs,either directly through other oscillators and is entrained by environmental cues.
What is a zeitgeber?
any external or environmental cues that entrains or synchronises an organisms biological rhythms to the earths 24- hour light dark cycle and 12 month cycle.Regular mealtimes and ligh are zeitgebergs.
What areas of the body are responsible for regulating this?
The primary mechanisms involve the timing of food consumption and the natural light- dark cycle.
What factors can affect this Cardio vascular tissue
,kidney,pancreas,gut,muscle,fat tissue
What can disturb this
exposure to 450-500nm of light at night or lack of light exposure in the morning.
What is the SCN
Suprachiasmatic nucleus
What is the role of it and where is it located?
The small area above the optic chiasm
in the anteroventral region of the hypothalamus.It is the master body clock and regulates other circadian rhytms- it is a circadian pacemaker.The master clock in the SCN is composed bilaterally paired nuclei which contain 8,000-10,000 clock cells packed together .The SCn receives light information via the retino-hypothalamic tract (RHT).The entrained SCN coordinates the timing of the slave oscillators in other areas of the brain (eg.cortex) and peripheral organs (heart,liver),regulating brain homeostasis,peripheral metabolism (glucose homeostasis),vascular and peripheral regulation and peripheral inflammation.The SCN also regulated amyloid plaque breakdown/removal.
What is melatonin
Entrainment is mediated by melatonin,a naturally occurring hormone which induces sleep.It is released in response to low levels of light
What is wakefulness?
The neurotransmitters involved in maintain wakefulness include acetylcholine,norepinephrine and serotonin and histamine.
Explain the ascending reticular formation
– the brain is kept awake by this – activity of the ascending reticular formation. The ascending reticulum formation projects to the thalamus and cerebral cortex. It exerts some control over which sensory signals reach the cerebrum and come to our conscious attention.Eg, if a loud noise is heard during sleep the signal is recived as an auditory impulse.Reticular formation radiates to the cerebral cortex, resulting in waking.Lesions to this brain area leads to constant sleep.
What is the ARAS
The ascending reticulum activating system
