SAMPLE FINAL PLUS PRACTICE MIDTERMS Flashcards
(124 cards)
Bright daylight can influence:
a. Amount of melatonin secreted in humans
b. Phase of onset of melatonin secreted in humans
c. Phase of onset of activity in hamsters
All of the above
If free running hamsters in constant lighting conditions are given a light pulse during the middle of the subjective day, this will:
Have little or no effect on the activity rhythm
Evidence from Hamsters suggests that the activity-rest circadian rhythm can be entrained to any period within:
18-26 hours
Biological rhythms observed in constant environmental conditions are said to be __________.
Free-running
If an appropriate __________________ is given, the rhythm is said to become _________________ to environmental conditions.
Zeitgeber, Entrained
In an early experiment by de Mairan, a mimosa plant was placed in a dark cabinet and temperature was held approximately constant.
The plant continued to show a daily rhythm of leaf movements, with leaves open during the day and folded at night.
This result indicates most conclusively that:
the natural daily rhythms of light and temperature are not required for rhythmic leaf movements
An experiment by de Candolle showed that the rhythmic leaf movements of the mimosa plant continued in constant darkness with a period length that was not exactly 24h.
This type of observation helped to convince biologists that:
some daily rhythms are driven by internal, self-sustained oscillators
A common feature of circadian, circannual, circatidal, and circalunar rhythms is that all of them:
are related to geophysical rhythms that may have some importance to organisms
As compared to homeostatic processes, biological rhythms seem to be much less dependent on:
internal negative feedback mechanisms
For a Nocturnal animal that is free-running under constant conditions, the beginning of the active phase (locomotor activity) corresponds approximately to:
beginning of subjective night (??)
The term “temperature compensation” is most clearly illustrated by the observation that:
mean environmental temperature has little effect on taudd
Differences between individuals of a species with respect to tau:
a. may result from genetic differences
b. may be a result of different photoperiod histories of the individuals
c. may be related to age
d. do not exist
e. “a” , “b”, and “c”
e.
“a” , “b”, and “c”
Rodents are most likely to become arrhythmic (non-rhythmic) when exposed to:
continuous light (LL)
If you wanted to estimate the limits of entrainment to light/dark cycles for a particular species, which of the following would provide helpful information:
the phase response curve and tau
For people on a normal day-night schedule, cortisol levels peak in the______________ and are lowest in_________________.
Early morning; early evening
The last link in the pathway to the pineal gland comes from the:
Superior cervical ganglia
All of the following are involved with mammalian photoperiodism except the
a. Pineal gland
b. Suprachiasmatic nucleus (SCN)
c. GnRH neurons
d. Hippocampus
Hippocampus
The Aschoff Rule states that
light intensity affects the period of a rhythm
A phase response curve (PRC) best describes
a rhythm’s entrainment properties
Which of the following exhibits clock properties in birds?
a. Suprachiasmatic nucleus
b. Pineal gland
c. The retina of the eye
d. both a and b
e. a, b, and c
d. both a and b
Suprachiasmatic nucleus,
Pineal gland
In general, seasonal reproduction in various avian and mammalian species is usually regulated by one of the following factors, but NOT
a. photoperiod
b. food availability
c. a circannual rhythm
d. temperature
Temperature
The critical feature of pineal gland function that causes short-day-induced gonadal regression in rodents is:
the duration of the daily melatonin rhythm
Biological clocks are involved in all of the following events, EXCEPT
a. the sun-arc hypothesis
b. photoperiod time measurement
c. night orientation to star patterns
d. the hibernation cycle of the ground squirrel
e. the feeding cycles of voles
night orientation to star patterns
Infradian rhythms refer to those rhythms with a period
that is more than 24 hours