Circadian Rhythm Flashcards
Part of hypothalamus that is concerned with setting circadian rhythm:
SCN
2 genes activated in the hypothalamus:
- CLK
- BMAL1
Clock (CLK) Gene
no circadian rhythm on its own; expressed pretty constantly over 24hrs
BMAL1 Gene
Increases at night
CLK and BMAL1 gene expression leads to the increase in transcription/translation of:
- Period Genes (Per1, Per2, Per3)
- Cryptochrome Genes (Cry1, Cry2)
Action of proteins coded by Period and Cryptochrome genes results in:
inhibition of CLK and BMLA1
Protein synthesis of what genes are most active during night?
CLK and BMAL1
On its own, the SCN of the hypothalamus creates a day that is how many hours long?
25
Entrainment
making day match day; match genes associated with circadian rhythm with sun/moon
During daylight, inputs from the Retino-Hypothalamic Tract to the SCN inhibit the:
Pineal Gland
NT released in SCN in presence of light:
Glutamate
Entrainment: Sun is Up
(1) Light enters retina and hits the melanoreceptors
(2) Signal travels in retino-hypothalamic tract to SCN
(3) Glutamate is released onto interneurons which activates them
(4) Interneurons secrete GABA onto Pineal Gland (inhibition)
(5) No melatonin released
Entrainment: Sun is Down
(1) No light enters retina so melanoreceptors aren’t stimulated
(2) Signal does not travel in retino-hypothalamic tract to SCN
(3) Glutamate is not released onto interneurons
(4) Interneurons do not secrete GABA onto pineal gland (disinhibition)
(5) Melatonin is released
Neurons in the ____ generate the circadian rhythm.
SCN
The protein products from ____ and ____ act as transcription factors to increase ____ and ____.
- CLK
- BMAL1
- Per
- Cry
