Biopsycholgy- Endogenous Pacemakers And Exogenous Pacemakers Flashcards
Endogenous pacemakers -
Internal body clocks that regulate many of our biological rhythms, such as the influence of the suprachiasmatic nucleus (SCN) on the sleep/wake cycle.
Exogenous zeitgebers -
External cues that may affect or entrain our biological rhythms, such as the influence of light on the sleep/wake cycle.
Sleep/wake cycle -
A daily cycle of biological activity based on a 24-hour period (circadian rhythm) that is influenced by regular variations in the environment, such as the alternation of night and day.
What are endogenous pacemakers?
Endogenous Pacemakers (A)
Internal body clocks that regulate biological rhythms, such as the sleep/wake cycle, with the suprachiasmatic nucleus (SCN) being a key pacemaker.
What are exogenous zeitgebers?
Exogenous Zeitgebers (A)
External cues that influence or reset biological rhythms, such as light affecting the sleep/wake cycle.
What is the sleep/wake cycle?
A 24-hour circadian rhythm influenced by environmental factors like light and dark, determining periods of wakefulness and sleep.
What is the role of the suprachiasmatic nucleus (SCN) in the sleep/wake cycle?
The SCN, located in the hypothalamus, acts as a primary endogenous pacemaker and controls circadian rhythms, including the sleep/wake cycle.
How has the role of the SCN been demonstrated in animals?
Studies like those by DeCoursey et al. (2000) and Ralph et al. (1990) show that the SCN influences the sleep/wake cycle in animals, and its disruption can lead to irregular cycles.
How does the pineal gland relate to the sleep/wake cycle?
The SCN signals the pineal gland to produce melatonin at night, promoting sleep, and melatonin production is inhibited during wakefulness.
How does light affect the sleep/wake cycle?
Light is a primary exogenous zeitgeber that resets the SCN, influencing the sleep/wake cycle and body processes like hormone regulation and blood circulation.
What did Campbell and Murphy’s study reveal about light as an exogenous zeitgeber?
Their study showed that light can be detected by skin receptors, influencing the sleep/wake cycle even without direct light exposure to the eyes.
How do social cues influence the sleep/wake cycle?
Social cues, such as parents’ schedules for eating and sleeping, help entrain infants’ sleep/wake cycles and can influence circadian rhythms and jet lag.
What is the concept of peripheral oscillators in the body?
Peripheral oscillators are circadian rhythms found in various body organs that can function independently of the SCN, though they are usually influenced by it.
What ethical concerns arise from animal studies on the sleep/wake cycle?
Animal studies, like those by DeCoursey et al., raise ethical concerns due to the harm caused to animals, such as exposure to predators after disrupting their sleep/wake cycles.
Are exogenous zeitgebers always effective in influencing the sleep/wake cycle?
No, studies of blind individuals and those in Arctic regions suggest that exogenous zeitgebers like light may have limited influence in certain conditions.
What methodological issues are raised in Campbell and Murphy’s study?
Critics argue that there may have been some light exposure to the participants’ eyes, which could have confounded the results, and isolating one zeitgeber (light) limits understanding of other factors.
How do endogenous pacemakers and exogenous zeitgebers interact in the sleep/wake cycle?
In real life, endogenous pacemakers (like the SCN) and exogenous zeitgebers (like light and social cues) interact to regulate the sleep/wake cycle, rather than functioning in isolation.
