CHAPTER 5.2: Sleep

Question 1

what are circadian rhythms

Answer 1

biological rhythms that have a 24 hr periodicity. ex sleep

Question 2

what is entrainment?

Answer 2

one of the reasons why we have the 24hr periodicity when it comes to sleep.

how we synchronize our sleep patterns due to external patterns (ex. light diminishing towards evening, lower temp, clocks)

Question 3

describe the pathway of light entrainment.

Answer 3

1. slowly diminishing light detecting by specialized ganglion cells in retina
2. light signals communicated via optic nerve to optic chiasm
3. suprachiasmic nucleus (SCN) above optic chiasm receives light info
4. SCN innervates pineal gland to stimulate release of melatonin
5. melatonin accumulates w darkness and then u sleep

Question 4

what are endogenous rhythms?

Answer 4

one of the reasons why we have 24hr periodicity when it comes to sleep.

“free running” biological rhythms generated by our body following about a 24 hour feedback loop independent of entrainment.

due to genetic feedback loops

Question 5

what are the two hypothesis for why we sleep?

Answer 5

restore and repair, preserve and protect

Question 6

describe the restore and repair hypothesis for why we sleep

Answer 6

sleep restores energy levels and allows for repairs to body from day to day activities. “physiological housekeeping”

proteins and stuff acc get synthesized more while sleeping!

Question 7

describe the preserve and protect hypothesis for why we sleep

Answer 7

sleep preserves energy and protects organism from harm.

ex. prey species sleep for tiny amounts of time in chunks, while predator species don’t need to be as vigilant so they sleep for longer stretches