Chapter 14: Biological Rhythms & Sleep

Question 0

entrainment (n.)

Answer 0

the process of synchronizing a biological rhythm to an environmental stimulus

Question 1

circadian rhythm (n.)

Answer 1

a pattern of behavioral, biochemical, or physiological fluctuation that has a 24-hour period

Question 2

ultradian rhythms (n.)

Answer 2

rhythms that are shorter than 24 hours; can last from minutes to several hours

Question 3

infradian rhythms (n.)

Answer 3

rhythms that have periods longer than a day

Question 4

What brain region controls circadian rhythms?

Answer 4

Suprachiasmatic nucleus (SCN) of the hypothalamus

Question 5

What are the four biological functions of sleep?

Answer 5

Energy conservation, niche adaptation, body restoration, and memory consolidation

Question 6

When an animal continues to display an activity cycle without any external cues about the time of day, the cycle is said to be ________.

Answer 6

free-running

Question 7

What is a zeitgeber?

Answer 7

An environmental cue that synchronizes circadian rhythms

Question 8

What are the four brain regions that regulate sleep?

Answer 8

Basal forebrain, brainstem reticular, pons, hypothalamus

Question 9

What sleep neurotransmitter does the basal forebrain regulate?

Answer 9

GABA

Question 10

What sleep neurotransmitter does the pons regulate?

Answer 10

ACh

Question 11

What sleep neurotransmitter does the brainstem reticular formation regulate?

Answer 11

ACh and norepinephrine

Question 12

What sleep neurotransmitter does the hypothalamus regulate?

Answer 12

Hypocretin

Question 13

What does the basal forebrain regulate for sleep?

Answer 13

Slow wave sleep (SWS)

Question 14

What does the brainstem reticular formation regulate for sleep?

Answer 14

Wakefulness

Question 15

What does the pons regulate for sleep?

Answer 15

REM sleep

Question 16

What does the hypothalamus regulate for sleep?

Answer 16

Organization of sleep patterns

Question 17

What happens to sleep patterns after a lesion in the suprachiasmatic nucleus?

Answer 17

There is some rhythmicity to the light/dark cycle; no free-running when exposed to constant light

Question 18

What happens with the SCN is removed and maintained in vitro?

Answer 18

Circadian rhythm is still maintained

Question 19

What happens if a tau mutant SCN (20 hour) is implanted?

Answer 19

The recipient takes on the 20 hour circadian cycle of the donor

Question 20

How does entrainment occur?

Answer 20

Light stimulates melanopsin-containing ganglion cells which releases glutamate at the SCN; glutamate increases transcription of per gene, producing entrainment

Question 21

Describe the functioning of the molecular clock.

Answer 21

Clock and Cycle form dimer; binds to DNA and promotes transcription of per and cry; per, cry, and tau form complex which inhibits Clock/Cycle activation, which inhibits per/cry transcription; per/cry break down, ending inhibition; feedback loop takes 24 hours.

Question 22

What are delta waves?

Answer 22

Low frequency, high amplitude waves

Question 23

At what stage of sleep do delta waves begin?

Answer 23

Stage 3 SWS

Question 24

What are alpha waves?

Answer 24

Low amplitude, high frequency waves

Question 25

Describe stage 1 SWS.

Answer 25

Alpha rhythm decreases, presence of vertex spikes

Question 26

Describe stage 2 SWS.

Answer 26

Sleep spindles and K complexes

Question 27

Describe stage 3 SWS.

Answer 27

Onset of delta waves

Question 28

Describe stage 4 SWS.

Answer 28

At least 1/2 delta waves

Question 29

Describe REM sleep.

Answer 29

Return to high frequency; “paradoxical sleep”