BIOLOGY 3UU3 Lecture Notes - Lecture 3: Proteasome, Adrenocorticotropic Hormone, Seasonal Affective Disorder
12 Apr 2017
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Document Summary
Hypothalamus and clock: central microprocessor regulating the brain and body. Pituitary hormones peripheral effector hormones act on tissue receptors signal from cytoplasm to nucleus: cortisol cytoplasmic receptor translocate into nucleus when bound. Resides in a paired scn nuclei in the hypothalamus: each contains 10-16k neurons, entrains 24h dark-light cycles. Cycle: external phenomena like the rotation of the earth or the lunar cycle. Rhythms: matching endogenous periodicities: daily rotation of the earth is a 24h cycle that entrains a circadian rhythm. Clock function emerges from a complex system of feedback loops. Transcriptional activation of period (per) & cryptochrome (cry) by heterodimers of clock and bmal1: clock/bmal1 dimer transcription factor that binds to regulatory sequences (e or. Clock box promoter elements) in promoters of per and cry: clock strongly phosphorylated moves from cytoplasm to nucleus. After translation of per and cry, forms a heterodimer to block transcriptional activation of themselves by blocking clock/bmal1 heterodimers.
