Question 1

Which of the following best describes the interaction between the homeostatic and circadian systems in sleep regulation according to the 2-process model?

Accepted Answer

They interact to consolidate wakefulness during the biological day and sleep during the biological night.

Question 2

Adenosine is thought to play a key role in homeostatic sleep regulation. Which statement best explains its function?

Accepted Answer

Adenosine levels increase during wakefulness, decrease during sleep, and are enhanced after prolonged wakefulness.

Question 3

Caffeine is known to affect sleep homeostasis. Which mechanism is responsible for this effect?

Accepted Answer

Caffeine acts as an adenosine receptor antagonist, blocking adenosine's sleep-promoting effects.

Question 4

Which genes are most responsive to photic entrainment in the molecular clock of the SCN?

Accepted Answer

Per1 and Per2

Question 5

A patient with a genetic variant in adenosine receptors reports that caffeine does not affect their sleep. What is the most likely explanation?

Accepted Answer

The variant alters the receptor so that caffeine cannot bind and block adenosine signaling.

Question 6

Which of the following best describes the role of the SCN in regulating corticosteroid rhythms?

Accepted Answer

The SCN regulates corticosteroid rhythms via both neural and hormonal pathways.

Question 7

Growth hormone release is most strongly influenced by which of the following?

Accepted Answer

Sleep, with a major increase occurring just after onset of sleep, especially during slow-wave sleep (SWS).

Question 8

Which hormone is primarily responsible for inhibiting growth hormone release?

Accepted Answer

Somatostatin (SST)

Question 9

Which of the following equations correctly represents the conversion of ATP to adenosine in the synaptic terminal?

Accepted Answer

$$\mathrm{ATP} \rightarrow \mathrm{ADP} \rightarrow \mathrm{AMP} \rightarrow \mathrm{Ado}$$

Question 10

Which scenario best illustrates the non-additive nature of Processes S and C in sleep regulation?

Accepted Answer

A shift worker can fall asleep easily after a night shift but has difficulty staying asleep due to misalignment of circadian and homeostatic processes.

Question 11

Which pathway best describes how light influences the molecular clock in the SCN?

Accepted Answer

Light activates retinal ganglion cells, which send signals to the SCN via the retinohypothalamic tract (RHT), influencing Per1 and Per2 gene expression.

Question 12

Which of the following best explains why caffeine attenuates EEG markers of sleep homeostasis after sleep deprivation?

Accepted Answer

Caffeine blocks adenosine receptors, preventing adenosine from promoting sleep and reducing EEG markers of sleep pressure.

Question 13

Which of the following is a plausible consequence of prolonged wakefulness on adenosine levels and sleep EEG?

Accepted Answer

Prolonged wakefulness increases adenosine levels, which enhances sleep EEG spectral power similar to adenosine analogues.

Question 14

Which of the following best describes the relationship between melatonin and corticosteroids during the sleep-wake cycle?

Accepted Answer

Melatonin peaks during the biological night while corticosteroids peak during the biological morning.

Question 15

Which of the following best explains the role of ipRGCs in sleep regulation?

Accepted Answer

ipRGCs are intrinsically photosensitive retinal ganglion cells that send synaptic inputs to VIP-expressing neurons in the SCN, regulating synchrony in SCN shell neurons.

Question 16

Which of the following equations represents the inhibition of growth hormone release by somatostatin?

Accepted Answer

$$	ext{SST} ightarrow 	ext{GHRIH} ightarrow 	ext{Inhibition of GH release}$$

Question 17

Which of the following best describes the effect of sleep deprivation on EEG spectral profiles?

Accepted Answer

Sleep deprivation enhances EEG spectral power, especially in slow-wave frequencies, similar to adenosine analogues.

Question 18

Which of the following best explains why shift workers often have difficulty staying asleep?

Accepted Answer

Misalignment between homeostatic and circadian processes leads to easy sleep onset but difficulty maintaining sleep.

Sleep Regulation: Homeostatic and Circadian Mechanisms, Molecular Pathways, and Hormonal Interactions

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