Sleep Physiology Examination Paper | MCQ Quiz | OmpathStudy Kenya

Question 1

Which thalamic nucleus is primarily responsible for relaying visual information to the cortex?

Accepted Answer

Lateral geniculate body — The lateral geniculate body relays visual information from the retina to the visual cortex, while the medial geniculate body handles auditory information.

Question 2

The neurotransmitter primarily released by the locus coeruleus that promotes wakefulness is:

Accepted Answer

Norepinephrine — The locus coeruleus is the primary source of norepinephrine in the brain and is a key component of the ascending arousal system.

Question 3

Sleep spindles are characteristic of which stage of NREM sleep?

Accepted Answer

Stage 2 — Sleep spindles (10-14 Hz bursts) are the defining feature of Stage 2 NREM sleep, generated by the thalamic reticular nucleus.

Question 4

The master circadian pacemaker is located in the:

Accepted Answer

Suprachiasmatic nucleus — The SCN receives direct input from the retina via the retinohypothalamic tract and coordinates circadian rhythms.

Question 5

PGO spikes during REM sleep originate from:

Accepted Answer

Pons → Geniculate → Occipital cortex — PGO spikes are generated in the pons and travel through the lateral geniculate nucleus to the occipital cortex, marking REM sleep onset.

Question 6

The EEG frequency range for alpha rhythm is:

Accepted Answer

8-13 Hz — Alpha rhythm (8-13 Hz) is seen in awake, resting adults with eyes closed.

Question 7

Which neurotransmitter is inhibitory and promotes sleep when released from the preoptic area?

Accepted Answer

GABA — GABA neurons in the preoptic area of the hypothalamus are sleep-promoting and inhibit arousal systems.

Question 8

The approximate duration of a complete sleep cycle is:

Accepted Answer

90 minutes — Sleep cycles average 90 minutes, with 4-6 cycles occurring during a typical 8-hour sleep period.

Question 9

Delta waves are most prominent during:

Accepted Answer

Stage 3 NREM — Delta waves (0.5-4 Hz) define Stage 3 NREM (slow-wave sleep).

Question 10

Melatonin is synthesized in the:

Accepted Answer

Pineal gland — The pineal gland produces melatonin in response to darkness, regulated by the SCN.

Question 11

Which of the following is characteristic of REM sleep?

Accepted Answer

Muscle atonia — REM sleep is characterized by muscle atonia to prevent acting out dreams.

Question 12

The percentage of REM sleep in full-term neonates is approximately:

Accepted Answer

50% — Full-term neonates spend about 50% of sleep time in REM, decreasing to 25% in adults.

Question 13

Beta rhythm is associated with:

Accepted Answer

Alert wakefulness — Beta rhythm (13-30 Hz) appears during focused attention and mental tasks.

Question 14

Orexin neurons are located in the:

Accepted Answer

Lateral hypothalamus — Orexin (hypocretin) neurons in the lateral hypothalamus stabilize sleep-wake transitions.

Question 15

The EEG in REM sleep shows:

Accepted Answer

Low-voltage, fast activity — REM sleep EEG resembles waking EEG, hence "paradoxical sleep."

Question 16

Chandelier cells in the cortex:

Accepted Answer

Target pyramidal cell axon initial segments — Chandelier cells are inhibitory interneurons that synapse on axon initial segments.

Question 17

The bulboreticular facilitatory area is most active during:

Accepted Answer

Morning awakening — This area becomes maximally active in the morning to overcome sleep-promoting influences.

Question 18

Which nucleus produces serotonin?

Accepted Answer

Raphe nuclei — The raphe nuclei in the brainstem are the primary source of serotonin.

Question 19

K-complexes are seen in:

Accepted Answer

Stage 2 NREM — K-complexes are large, slow waves appearing in Stage 2 NREM sleep.

Question 20

The retinohypothalamic tract carries information about:

Accepted Answer

Light-dark cycles — This tract carries non-visual light information to the SCN for circadian regulation.

Question 21

Histamine promotes wakefulness and is released from:

Accepted Answer

Tuberomammillary nucleus — The tuberomammillary nucleus in the posterior hypothalamus releases histamine.

Question 22

Which sleep stage is most restorative?

Accepted Answer

Stage 3 NREM — Stage 3 NREM (slow-wave sleep) is the most restorative stage.

Question 23

The ascending arousal system is primarily:

Accepted Answer

Polysynaptic — It involves multiple synaptic connections from the brainstem and hypothalamus to the cortex.

Question 24

Dreams are most vivid and memorable during:

Accepted Answer

REM sleep — REM sleep is associated with vivid, memorable dreaming.

Question 25

Light exposure suppresses melatonin by affecting:

Accepted Answer

Suprachiasmatic nucleus — Light activates the SCN, which inhibits melatonin synthesis via sympathetic pathways.

Question 26

The thalamic reticular nucleus releases:

Accepted Answer

GABA — The thalamic reticular nucleus is GABAergic and generates sleep spindles.

Question 27

As the night progresses, there is typically:

Accepted Answer

Increased REM sleep — REM episodes become longer toward morning, while deep NREM sleep decreases.

Question 28

The EEG reflects:

Accepted Answer

Postsynaptic potentials — EEG records summated postsynaptic potentials from dendrites in superficial cortical layers.

Question 29

Acetylcholine's role in sleep is complex because it:

Accepted Answer

Promotes different aspects of both sleep and wake — Acetylcholine promotes wakefulness and also triggers REM sleep.

Question 30

The VPL and VPM nuclei relay:

Accepted Answer

Somatosensory information — VPL and VPM nuclei relay somatosensory information to the postcentral gyrus.

Question 31

Muscle atonia during REM sleep is caused by:

Accepted Answer

Spinal motor neuron inhibition — REM sleep involves active inhibition of spinal motor neurons.

Question 32

The percentage of total sleep time occupied by NREM sleep is approximately:

Accepted Answer

75-80% — NREM sleep occupies about 75-80% of total sleep time.

Question 33

Sleep spindles are generated by:

Accepted Answer

Thalamic reticular nucleus — Sleep spindles are generated by rhythmic inhibition of thalamocortical relay neurons.

Question 34

Which brain region is most active during REM sleep?

Accepted Answer

Brainstem — The brainstem, particularly the pons, is highly active during REM sleep.

Question 35

Slow-wave sleep is characterized by:

Accepted Answer

Low-frequency, high-amplitude waves — Stage 3 NREM is defined by slow, high-amplitude delta waves.

Question 36

The pedunculopontine nucleus releases:

Accepted Answer

Acetylcholine — The pedunculopontine nucleus releases acetylcholine as part of the arousal system.

Question 37

Alpha blocking occurs when:

Accepted Answer

Attention is focused — Alpha rhythm is replaced by beta rhythm when attention is focused.

Question 38

Brain metabolism during REM sleep is:

Accepted Answer

Increased by 20% — Brain metabolism increases during REM sleep, reflecting high neural activity.

Question 39

The arousal threshold is highest during:

Accepted Answer

REM sleep — Despite paradoxical brain activity, the arousal threshold is highest during REM sleep.

Question 40

Children compared to adults have:

Accepted Answer

More Stage 4 sleep — Children have significantly more Stage 4 (deep) sleep than adults.

Sleep Physiology Examination Paper | MCQ Quiz | OmpathStudy Kenya

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