Sleep Physiology Examination Paper – 40 MCQs | Kenya MBChB

40 Year 2: Physiology exam questions on Sleep Physiology Examination Paper for medical students. Includes MCQs, answers, explanations and written questions. Sam

This MCQ set contains 40 questions on Sleep Physiology Examination Paper in the Year 2: Physiology unit. Each question includes the correct answer and a detailed explanation for active recall and exam preparation.

Q1: Which thalamic nucleus is primarily responsible for relaying visual information to the cortex?

  1. A. Medial geniculate body
  2. B. Lateral geniculate body
  3. C. VPL nucleus
  4. D. Anterior nucleus
  5. E. Lateral geniculate body

Correct answer: B – 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.

Q2: The neurotransmitter primarily released by the locus coeruleus that promotes wakefulness is:

  1. A. Serotonin
  2. B. GABA
  3. C. Norepinephrine
  4. D. Acetylcholine
  5. E. Norepinephrine

Correct answer: C – Norepinephrine

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

Q3: Sleep spindles are characteristic of which stage of NREM sleep?

  1. A. Stage 1
  2. B. Stage 2
  3. C. Stage 3
  4. D. REM sleep
  5. E. Stage 2

Correct answer: B – Stage 2

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

Q4: The master circadian pacemaker is located in the:

  1. A. Pineal gland
  2. B. Suprachiasmatic nucleus
  3. C. Locus coeruleus
  4. D. Raphe nuclei
  5. E. Suprachiasmatic nucleus

Correct answer: B – Suprachiasmatic nucleus

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

Q5: PGO spikes during REM sleep originate from:

  1. A. Pons → Geniculate → Occipital cortex
  2. B. Parietal → Geniculate → Occipital cortex
  3. C. Pons → Globus pallidus → Occipital cortex
  4. D. Pineal → Geniculate → Occipital cortex
  5. E. Pons → Geniculate → Occipital cortex

Correct answer: A – 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.

Q6: The EEG frequency range for alpha rhythm is:

  1. A. 4-7 Hz
  2. B. 8-13 Hz
  3. C. 13-30 Hz
  4. D. 30-100 Hz
  5. E. 8-13 Hz

Correct answer: B – 8-13 Hz

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

Q7: Which neurotransmitter is inhibitory and promotes sleep when released from the preoptic area?

  1. A. Glutamate
  2. B. Histamine
  3. C. GABA
  4. D. Orexin
  5. E. GABA

Correct answer: C – GABA

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

Q8: The approximate duration of a complete sleep cycle is:

  1. A. 60 minutes
  2. B. 90 minutes
  3. C. 120 minutes
  4. D. 150 minutes
  5. E. 90 minutes

Correct answer: B – 90 minutes

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

Q9: Delta waves are most prominent during:

  1. A. REM sleep
  2. B. Stage 1 NREM
  3. C. Stage 2 NREM
  4. D. Stage 3 NREM
  5. E. Stage 3 NREM

Correct answer: D – Stage 3 NREM

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

Q10: Melatonin is synthesized in the:

  1. A. Hypothalamus
  2. B. Pineal gland
  3. C. Thalamus
  4. D. Brainstem
  5. E. Pineal gland

Correct answer: B – Pineal gland

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

Q11: Which of the following is characteristic of REM sleep?

  1. A. High muscle tone
  2. B. Slow eye movements
  3. C. Muscle atonia
  4. D. High-amplitude EEG waves
  5. E. Muscle atonia

Correct answer: C – Muscle atonia

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

Q12: The percentage of REM sleep in full-term neonates is approximately:

  1. A. 25%
  2. B. 50%
  3. C. 75%
  4. D. 80%
  5. E. 50%

Correct answer: B – 50%

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

Q13: Beta rhythm is associated with:

  1. A. Deep sleep
  2. B. Drowsiness
  3. C. Alert wakefulness
  4. D. Coma
  5. E. Alert wakefulness

Correct answer: C – Alert wakefulness

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

Q14: Orexin neurons are located in the:

  1. A. Brainstem
  2. B. Thalamus
  3. C. Lateral hypothalamus
  4. D. Cortex
  5. E. Lateral hypothalamus

Correct answer: C – Lateral hypothalamus

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

Q15: The EEG in REM sleep shows:

  1. A. High-voltage, slow waves
  2. B. Sleep spindles
  3. C. Low-voltage, fast activity
  4. D. Delta waves
  5. E. Low-voltage, fast activity

Correct answer: C – Low-voltage, fast activity

REM sleep EEG resembles waking EEG, hence "paradoxical sleep."

Q16: Chandelier cells in the cortex:

  1. A. Release glutamate
  2. B. Target pyramidal cell axon initial segments
  3. C. Promote excitation
  4. D. Are located in deep cortical layers
  5. E. Target pyramidal cell axon initial segments

Correct answer: B – Target pyramidal cell axon initial segments

Chandelier cells are inhibitory interneurons that synapse on axon initial segments.

Q17: The bulboreticular facilitatory area is most active during:

  1. A. REM sleep
  2. B. Deep NREM sleep
  3. C. Morning awakening
  4. D. Dream states
  5. E. Morning awakening

Correct answer: C – Morning awakening

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

Q18: Which nucleus produces serotonin?

  1. A. Locus coeruleus
  2. B. Raphe nuclei
  3. C. Tuberomammillary nucleus
  4. D. Suprachiasmatic nucleus
  5. E. Raphe nuclei

Correct answer: B – Raphe nuclei

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

Q19: K-complexes are seen in:

  1. A. Stage 1 NREM
  2. B. Stage 2 NREM
  3. C. Stage 3 NREM
  4. D. REM sleep
  5. E. Stage 2 NREM

Correct answer: B – Stage 2 NREM

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

Q20: The retinohypothalamic tract carries information about:

  1. A. Visual images
  2. B. Light-dark cycles
  3. C. Color perception
  4. D. Visual motion
  5. E. Light-dark cycles

Correct answer: B – Light-dark cycles

This tract carries non-visual light information to the SCN for circadian regulation.

Q21: Histamine promotes wakefulness and is released from:

  1. A. Locus coeruleus
  2. B. Raphe nuclei
  3. C. Tuberomammillary nucleus
  4. D. Pedunculopontine nucleus
  5. E. Tuberomammillary nucleus

Correct answer: C – Tuberomammillary nucleus

The tuberomammillary nucleus in the posterior hypothalamus releases histamine.

Q22: Which sleep stage is most restorative?

  1. A. Stage 1 NREM
  2. B. Stage 2 NREM
  3. C. Stage 3 NREM
  4. D. REM sleep
  5. E. Stage 3 NREM

Correct answer: C – Stage 3 NREM

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

Q23: The ascending arousal system is primarily:

  1. A. Monosynaptic
  2. B. Polysynaptic
  3. C. Inhibitory
  4. D. Cortical
  5. E. Polysynaptic

Correct answer: B – Polysynaptic

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

Q24: Dreams are most vivid and memorable during:

  1. A. Stage 1 NREM
  2. B. Stage 2 NREM
  3. C. Stage 3 NREM
  4. D. REM sleep
  5. E. REM sleep

Correct answer: D – REM sleep

REM sleep is associated with vivid, memorable dreaming.

Q25: Light exposure suppresses melatonin by affecting:

  1. A. Pineal gland directly
  2. B. Suprachiasmatic nucleus
  3. C. Hypothalamus generally
  4. D. Retina only
  5. E. Suprachiasmatic nucleus

Correct answer: B – Suprachiasmatic nucleus

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

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