Biological Rhythms and Sleep

Question 1

regular fluctuations in any living process

Answer 1

biological rhythms

Question 2

have a period of about 24 hours

Answer 2

circadian rhythms

Question 3

repeat more than once a day, such as bouts of activity, feeding and hormone release

Answer 3

ultradian rhythms

Question 4

repeat less frequently than once a day, such as reproductive cycles

Answer 4

infradian rhythms

Question 5

animals are active during the day

Answer 5

diurnal

Question 6

animals are active during the dark period

Answer 6

nocturnal

Question 7

animals are active at dawn and dusk

Answer 7

crepuscular

Question 8

when rhythmic activity is controlled by external factors

Answer 8

exogenous control of rhythms

Question 9

internal timing mechanisms that mediate many observed rhythms in physiology and behavior

Answer 9

endogenous control

Question 10

is the process of using a stimulus to synchronize the rhythm

Answer 10

entrainment

Question 11

the cue that an animal uses to synchronize with the environment is Called a … or “time giver”

Answer 11

zeitgeber

Question 12

a … is a shift in activity in response to a synchronizing stimulus such as light

Answer 12

phase shift

Question 13

a … animal is maintaining its own cycle without external cues, such as changes in light intensity

Answer 13

free-running

Question 14

circadian rhythms are generated by an endogenous (internal) clock

• they enable animals to anticipate an event and begin physiological and behavioral preparations before the event

Answer 14

what is their benefit?

Question 15

the biological clock is located in the … in the hypothalamus above the optic chiasm

lesions of the SCN eliminate circadian rhythms of drinking, locomotion and hormone secretion

Answer 15

suprachiasmatic nucleus (SCN)

Question 16

circadian rhythms entrain to light-dark cycles using different pathways, some are outside of the eye, as Is the case of many vertebrates (e.g., the … in bits and amphibians)

Answer 16

pineal gland or “third eye”

Question 17

in mammals, some retinal ganglion cells form the …. which carries light info from the eye to the SCN

Answer 17

retinohypothalimic pathway

Question 18

the pineal gland secretes … when its dark out, which also informs the brain about time of day

Answer 18

melatonin

• this is one reason we get sleepy earlier in the day in the winter

Question 19

record electrical activity in the brain that can be used to classify levels of arousal and sleep

Answer 19

electroencephalographs (EEG)

Question 20

characterized by small amplitude, fast EEG waves; no postural tension; and rapid eye movements

Answer 20

rapid eye movement sleep (REM)

Question 21

can be divided into three stages and is characterized by distinctly different EEG waves than REM sleep

Answer 21

Non REM sleep