BRPT Sleep Physiology and Neuroanatomy

Question 1

Which neurotransmitter, produced by the lateral hypothalamus, is the primary promoter of wakefulness and is deficient in narcolepsy type 1?

Accepted Answer

Orexin (hypocretin)

Answer

Orexin (hypocretin) neurons in the lateral hypothalamus stabilize wakefulness, and their loss causes narcolepsy type 1 with cataplexy.

Question 2

The suprachiasmatic nucleus (SCN), which serves as the master circadian pacemaker, is located in which brain structure?

Accepted Answer

Hypothalamus

Answer

The SCN in the anterior hypothalamus receives light input via the retinohypothalamic tract and coordinates circadian timing throughout the body.

Question 3

Which hormone, secreted by the pineal gland in response to darkness, signals the circadian system to promote sleepiness?

Accepted Answer

Melatonin

Answer

Melatonin is released by the pineal gland during darkness and acts on SCN receptors to facilitate sleep onset and timing.

Question 4

What is the typical duration of one complete NREM-REM sleep cycle in healthy adults?

Accepted Answer

90–110 minutes

Answer

A complete sleep cycle averaging 90–110 minutes repeats 4–6 times per night, with REM periods lengthening in later cycles.

Question 5

Growth hormone secretion is predominantly linked to which sleep stage?

Accepted Answer

N3 (slow-wave) sleep

Answer

Growth hormone is released in pulses tightly coupled to N3 slow-wave sleep, particularly in the first sleep cycle of the night.

BRPT - Board of Registered Polysomnographic Technologists Practice Test