Circadian Control Flashcards
What is the function of the circadian clock, and how does it work on the molecular level?
The circadian clock is responsible for regulating various physiological processes in a 24-hour rhythm. It helps synchronize biological functions with the environmental day-night cycle. On the molecular level, the circadian clock involves a network of genes and proteins that generate oscillations. The key players include transcriptional activators (CLOCK, BMAL1) and repressors (PER, CRY), which undergo rhythmic expression and form feedback loops to regulate gene expression over the course of the day.
What are central (SCN) and peripheral clocks, and how are they synchronized?
The suprachiasmatic nucleus (SCN) in the brain’s hypothalamus is the central clock that serves as the master pacemaker, receiving light signals from the retina to synchronize with the external environment. Peripheral clocks exist in various organs and tissues. They are synchronized by signals from the central clock, as well as by local cues such as feeding and temperature changes.
Can you provide some examples of endocrine rhythms and their functions?
Examples of endocrine rhythms include the daily variation in hormone secretion, such as cortisol, melatonin, growth hormone, and thyroid-stimulating hormone (TSH). These rhythms help regulate processes like sleep-wake cycles, metabolism, immune function, and reproductive processes.
What are the implications for health when the circadian clock is disrupted?
Disruption of the circadian clock, such as through shift work, irregular sleep patterns, or exposure to artificial light at night, can have adverse health effects. It is associated with increased risk of metabolic disorders (e.g., obesity, diabetes), mood disorders, cardiovascular disease, compromised immune function, and disturbances in sleep-wake cycles.
