Ultradian rhythms

Question 1

what is an ultradian rhythm

Answer 1

a biological rhythm that occurs more than once in a 24 hour period, such as the sleep cycle and the basic rest activity cycle (BRAC)

Question 2

what is the sleep cycle

Answer 2

a recurring ultradian rhythm that lasts approximately 90 minutes, during which the brain cycles through different stages of sleep, including both non-REM and REM sleep

Question 3

what is NREM sleep

Answer 3

the first stages of the sleep cycle, typically divided into stages 1-4, characterised by progressively deeper sleep and slower brain waves

Question 4

what is stage one of the sleep cycle

Answer 4

light sleep, may experience jerks

Question 5

what is stage two of the sleep cycle

Answer 5

slightly deeper sleep, with sleep spindles and k-complexes

Question 6

what are sages 3 and 4 of the sleep cycle

Answer 6

deep sleep, dominated by delta waves

Question 7

what is REM sleep

Answer 7

a stage of sleep where the brain is highly active, dreaming occurs, and the eyes move rapidly under the eyelids. it is sometimes called paradoxical sleep because the brain is active while the body is physically inactive.

Question 8

what is the sleep architecture

Answer 8

the structure and pattern of the different sleep stages over the course of a night, often shown in a hypnogram. a typical night includes 4-5 sleep cycles

Question 9

what is the BRAC

Answer 9

proposed by Kleitman, this is a 90-minute cycle of alertness and fatigue that continues throughout the day, similar in duration to the sleep cycle.