Biological Rhythm And Sleep Summary

Question 1

What are biological rhythms?

Answer 1

Repeating cycles of behaviour or physiology regulated by internal clocks

Question 2

What are the types of biological rhythms?

Answer 2

• Circadian (~24 hours)
• Ultradian (<24 hours)
• Infradian (>24 hours)

Question 3

What is an exogenous rhythm?

Answer 3

Rhythms controlled by external cues (light, temperature)

Question 4

What is an endogenous rhythm?

Answer 4

Rhythms controlled by internal pacemaker (genetic/brain-based)

Question 5

What was the conclusion of the testing conducted by Minors & Waterhouse (1981)?

Answer 5

The body clock is internal (endogenous)

Question 6

What is a zeitgeber?

Answer 6

An external cue that resets the body clock

Question 7

What is the main zeitgeber for the body clock?

Answer 7

Light

Question 8

What is entrainment?

Answer 8

The process by which the body clock aligns to external cues

Question 9

Where is the SCN located?

Answer 9

In the ventro-rostral hypothalamus, just above the optic chiasm

Question 10

What is the function of the SCN?

Answer 10

Acts as the master pacemaker for circadian rhythms

Question 11

What happens to rhythms if there are lesions to the SCN?

Answer 11

Arrhythmic sleep, eating, hormone secretion

Question 12

What role does the pineal gland play in seasonal rhythms?

Answer 12

Releases melatonin, more at night and during longer winter nights

Question 13

What effect do SCN lesions have on seasonal rhythms?

Answer 13

Abolish seasonal rhythms

Question 14

What is the cycle duration in fruit flies (Drosophila)?

Answer 14

Approximately 24 hours

Question 15

What is the function of the gene ‘per’ in fruit flies?

Answer 15

Produces PER proteins that inhibit their own genes

Question 16

What neurotransmitter promotes wakefulness?

Answer 16

Orexin

Question 17

What are the stages of brain activity during sleep?

Answer 17

• Awake - Beta
• Relaxed - Alpha
• Stage 1 - Theta
• Stage 2 - Theta + Spindles
• Stage 3 & 4 - Delta
• REM - Beta-like

Question 18

What is the function of SWS?

Answer 18

Restorative sleep, immune repair, consolidates declarative memory

Question 19

What is REM sleep associated with?

Answer 19

Brain development, learning, emotional processing, non-declarative memory

Question 20

What is a common effect of sleep deprivation in humans?

Answer 20

Hallucinations, confusion, poor focus

Question 21

What is REM rebound?

Answer 21

After REM deprivation, brain increases REM the next night

Question 22

What is insomnia?

Answer 22

Trouble falling or staying asleep

Question 23

What is sleep apnea?

Answer 23

Stop breathing during sleep; wake when CO₂ rises

Question 24

What is narcolepsy?

Answer 24

Sudden sleep attacks during the day

Question 25

What neurotransmitter is blocked by caffeine?

Answer 25

Adenosine

Question 26

What is the function of melatonin?

Answer 26

Makes us drowsy

Question 27

What happens to sleep patterns in elderly individuals?

Answer 27

Less REM and Stage 4; shorter cycles

Question 28

What is the function of the gene 'cry' in mammals?

Answer 28

Absorbs blue light and degrades TIM

Question 29

Fill in the blank: The SCN is the ________ pacemaker.

Answer 29

master

Question 30

True or False: Sleep is an active process.

Answer 30

True

Question 31

What neurotransmitters promote wakefulness?

Answer 31

* Acetylcholine (ACh) * Norepinephrine (NE) * Serotonin (5-HT) * Histamine

Question 32

What is the role of the SCN in seasonal rhythms?

Answer 32

Coordinates the release of melatonin

Question 33

What type of rhythm is associated with the menstrual cycle?

Answer 33

Infradian rhythm