1- How does our Day-Night Cycle Work? Flashcards
Where is the main biological clock located?
In the suprachiasmatic nuclei (SCN) of the hypothalamus
Why do biological clocks tend to be located very deep inside our brains?
It is hard to get to and unlikely to be disrupted by damage
What supporting evidence did Ibuka & Kawamura, 1975 produce in support of the SCN?
Lesions of SCN disrupt daily cycles in rats
What do SCN neurons correlate with?
The day-night cycle
What cells in our eye tell us that it’s time to go to sleep?
Melanopsin-containing ganglion cells
Where do melanopsin-containing ganglion cells go after they’ve picked up light information?
Go along the retinohypothalamic pathway
How do melanopsin-containing ganglion cells affect the day-night cycle?
Transmit light info from eye to rest of brain
What does CLOCK stand for in CLOCK genes?
Circadian Locomotor Output Kaput
What do CLOCK genes do?
Encode proteins regulating circadian rhythms
How do CLOCK genes work?
- Protein enters nucleus
- Suppress the gene
- No more mRNA is made
- Level of protein falls, gene becomes active again
- Gene is active and mRNA leaves nucleus, causing protein production
What 2 processes are in the 2-process of sleep?
Sleep-dependent process and sleep-independent circadian process
What does the sleep-dependent process show?
An exponential decline in sleep and increase in waking- function of prior waking time
How is the sleep-independent circadian process controlled?
By the circadian oscillator
What does the 2-process model of sleep propose?
Sleep duration and sleep propensity are driven by these two processes
