PHR 936 Sleep anatomy

How much sleep does the typical adult need?

7-9 hours

What is the process of memory consolidation that occurs during sleep?

Hippocampal-cortical memory consolidation

Glymphatic activity occurs during what type of sleep and what does it do?

Glymphatic activity occurs during deep sleep and helps removes toxins and beta-amyloid from the CNS

What are the 4 stages of sleep?

NREM 1, NREM 2, NREM 3, and REM sleep

What is NREM stage 1 sleep and how long does it last?

Transition period between wakefulness and sleep and lasts 5-10mins

What is NREM stage 2 sleep and how long does it last?

Body temp drops, HR begins to slow, and brain begins to produce sleep spindles and lasts about 20 mins

What is NREM stage 3 sleep?

This is the deepest sleep where the muscles relax, blood pressure and breathing rate drop, and

What is REM sleep?

The active form of sleep for the brain in which the body becomes immobilized, dreams occur, and eyes move more rapidly

What are the two drivers of sleep?

Circadian rhythm and sleep pressure

What is the circadian rhythm?

The homeostatic process informed by the outside environment

What hormone drives sleep, what part of the brain regulates it, and what part of the brain secretes it?

Melatonin drives sleep, is regulated by the sub chiasmatic nucleus and is secreted by the pineal gland

What are the two main melatonin receptors in the subchaismatic nucleus and what are their functions?

MT1 receptors function as entrainment to light and dark cycles and MT2 receptors are phase shifting (sleep to wake)

What is the main wakefulness hormone, what is its role in sleep, and what are its non-sleep functions?

Cortisol is the main wakefulness hormone, heightens memory and attention, and is involved in BP, BG, pain sensitivity, and immune supression

What is sleep pressure?

Adenosine receptor stimulation by adenosine (breakdown product of ATP), to promote sleep

What does the recycling of adenosine overnight help with and why?

Recycling of adenosine overnight helps promote wakefulness the next morning

What is caffiene's role in sleep pressure?

Adenosine receptor antagonist to prevent adenosine form binding to thus result in less sleepiness

What are some of the other wakefulness hormones?

ACh, His, DA, NE, 5HT, and Orexin

What are orexins?

Neuropeptides involved in the regulations of feeding behaviors and sleep-wake cycles

What does orexin A bind to? What does orexin B bind to?

Orexin A binds to ORX1 and 2 and Orexin B binds selectively to ORX2

What is ORX1 involved in?

Arousal and wakefulness

What is ORX2 involved in?

Sleep/wake cycles, feeding, and energy homeostasis

By what age has the suprachiasmatic nucleus developed to begin circadian signals?

1yr old

What stages of sleep are reduced in elderly individuals?

Deep and REM sleep

What is the gold standard for assessing sleep?

Ploysomnography

What is the reliability of actinography?

60-80%