Flashcards in Chapter 8 - Wakefulness & Sleep Deck (90)
In humans, the sun, alarm clocks, and eating (feedings) are all ________ that help maintain endogenous ________ rhythms.
The daily pattern of human temperature is highest around ____ hours from sleep time, and lowest around _____ hours into sleep.
6 hours; 2 hours.
The purpose of the circadian rhythm is to?
To keep our internal workings in phase with the outside world.
A stimulus that resets circadian rhythms is? The most potent for land animals is? For animals at sea?
A Zeitgerber; sunlight; tides.
Light intensity, temperature, food availability, and social interactions are all examples of stimuli known as _________.
Due to alternating between 45' of light and 45' of darkness, astronaut often experience? What other group of scientists might experience this?
Depression and cognitive impairment; scientists in the antarctic.
In Germany, the east side experiences sunrise ~30' earlier than their western counterparts. What does this due to their circadian rhythms?
People on the east tend to go to bed earlier and wake earlier.
How might blind people set their circadian rhythms?
Noise, temperature, meals, and activity
Humans vs. squirrels - what's the length of the biological clock for each?
Humans slightly >24hrs; squirrels slightly <24hrs.
Regarding jet lag, which direction is easiest to travel from/to, and why?
From east to west because it's easier to stay up later than to try to go to sleep earlier (circadian rhythm is slightly >24hrs).
Regarding jet lag, traveling east causes a ____-_____ in our circadian rhythm while traveling west causes a ____-_____. Which is 'easier'?
phase-advance; phase-delay. Phase-delay (traveling west) is easier - it's harder to go to bed earlier.
Jet lag can case elevations in what hormone? Prolonged exposure (as evidenced in flight attendants) can damage what?
Elevates cortisol levels; damage to the hippocampus which causes memory impairments.
Circadian rhythms in all animals change as a function of their _____. Why might this be?
Age; staying up later during late adolescence to early adulthood may be due to sex hormones and increased mating.
The main control center of the circadian rhythms for sleep and body temperature is the ____ ____? Where is it located?
surprachiasmatic nucleus (SCN); located above the optic chiasm
Circadian rhythms generated by the SCN are controlled by? What is the significance of a single SCN cell in a culture?
genetics; it will keep the circadian rhythm all on its own.
SCN cells transplanted from a mutated mouse with a 20 hr rhythm to a normal mouse will do what? How about transplanting the reverse?
A normal mouse will have the circadian rhythm of the donor SCN cells; a mouse with the mutation will have the rhythm of the healthy donor mouse.
The _____ path of the optic nerve alters the SCN's settings due to the presence of _______ in the retinal ganglion cells of this path.
retinohypothalamic path; melanopsin
Mice that have a genetic defect which renders them nearly blind can maintain a circadian rhythm due to?
The presence of the ganglion cells with melanopsin and the the retinohypothalamic path.
Blind mole rats can see light because of the presence of the _________ path, but they need ____, ____-____ light in order to activate.
retinohypothalamic path; sustained, blue-wave light.
What condition stimulates the ganglions of the retinohypothalamic path?
Animal studies from this animal revealed several genes responsible for circadian rhythms, including the period and timeless genes.
The production of these two circadian proteins (name them) is controlled by what? What causes production, and when is production increased? Decreased?
An automatic feedback loop controls the production of PER and TIM proteins. mRNA is responsible for production, and it increases throughout the day. Once the concentration of PER and TIM are high, mRNA is inhibited.
How are PER and TIM concentrations reduced, and why are they reduced?
Light activates chemicals that break them down which helps keep synch with the environment.
The SCN regulates waking and sleeping by _____ activity levels in other areas of the brain including the _____ gland - an endocrine gland posterior to the thalamus that secretes ______.
controlling; pineal; melatonin.
_______ is a hormone secreted by animals that helps to induce sleep in diurnal animals and wakefulness in nocturnal animals.
Sleep is a state that the brain passively/actively produces.
A coma is categorized by extended unconsciousness and _____ brain activity with ______ response to stimuli.
A vegetative state is categorized by alternations between _____ and moderate _____ with/without purposeful action. Also, they respond to stimuli, like pain, by?
sleep and moderate arousal; without. Increased heart rate.
A minimally conscious state is categorized by alternations between _____ and moderate _____ with/without purposeful action.
sleep and moderate arousal; with.