Biological Clock and Circadian Rhythm

Circa 24 hours a day

Anterior of hypothalamus, dorsal to the optic chiasm, and lateral to 3rd ventricle

Core region expresses VIP and GRP, while the shell region expresses AVP

<p>Through gap junctions and neurotransmitter exchange from core to shell</p> Signup and view all the answers

<p>To ensure behavioral and physiological rhythms are coordinated with the external environment</p> Signup and view all the answers

<p>Transcription-translation feedback loop (TTFL) regulating clock genes</p> Signup and view all the answers

<p>The primary loop involves BMAL1/2 and Clock, while the secondary loop involves additional genes</p> Signup and view all the answers

<p>They form a negative feedback loop on BMAL1/clock and on themselves</p> Signup and view all the answers

<p>When traveling westward, you need to delay the clock, whereas when traveling eastward, you need to advance the clock.</p> Signup and view all the answers

<p>Melatonin acts on MT1 receptors, inhibiting cAMP signaling and linoleic acid uptake, thereby preventing growth pathways and reducing the risk of cancer.</p> Signup and view all the answers

<p>Melatonin regulates metabolic processes by regulating the expression of clock genes and metabolic pathways.</p> Signup and view all the answers

<p>ROR regulates the activation of BMAL1, while REV-ERB inhibits BMAL1 transcription.</p> Signup and view all the answers

<p>PGC1α is a co-activator of ROR and PPAR, regulating mitochondrial biogenesis, thermogenesis, and gluconeogenesis.</p> Signup and view all the answers

<p>SIRT1 is activated by high NAD+ ratio, deacetylating histones and silencing Per2, while AMPK is activated by high AMP ratio, phosphorylating Cry and CKIe, degrading Per2 and shifting phase.</p> Signup and view all the answers

<p>The pancreatic clock controls insulin secretion, and melatonin binds to MT1/2, inhibiting cAMP and decreasing insulin release.</p> Signup and view all the answers

<p>The circadian rhythm regulates metabolic health through the connection between clock genes and metabolic pathways, influencing metabolic processes such as mitochondrial biogenesis, thermogenesis, and gluconeogenesis.</p> Signup and view all the answers

<p>REV-ERB inhibits RORE inhibition of BMAL1.</p> Signup and view all the answers

<p>Light is the most important zeitgeber because it resets the clock every day.</p> Signup and view all the answers

<p>Light incidence, retinal ganglion cells, melanopsin, retinohypothalamic tract, SCN, and release of glutamate and PACAP.</p> Signup and view all the answers

<p>During early nights, light exposure decreases Per1&amp;2 levels, causing a permanent phase delay. During late nights, light exposure increases Per1&amp;2 levels, causing a permanent phase advance.</p> Signup and view all the answers

<p>The IGL receives indirect photic entrainment signals and sends them to the SCN via the GHT, regulating the circadian rhythm.</p> Signup and view all the answers

<p>The SCN regulates melatonin release by activating the PVN during the day, causing inhibitory GABA signaling, and inhibiting the PVN at night, causing melatonin release.</p> Signup and view all the answers

<p>Cortisol levels are regulated by the SCN, peaking in the morning and decreasing at night.</p> Signup and view all the answers

<p>Jet lag is a circadian misalignment caused by traveling across 3+ time zones, resulting in symptoms such as sleepiness, concentration problems, and gastrointestinal issues.</p> Signup and view all the answers