Wakefulness and Sleep

Question 1

Endogenous circadian rhythm

Answer 1

Internal mechanisms that operate on a 24 hour cycle. i.e.. wakefulness & sleep, eating & drinking, body temp.

Question 2

Human circadian rhythm is longer/shorter than 24 hours?

Answer 2

Longer

Question 3

External cues are important for keeping circadian rhythms on track - true/false

Answer 3

true

Question 4

Zeitgeber “time giver”

Answer 4

A stimulus that resets circadian rhythm - tides, sunlight, arousal, meals, environmental temp.

Question 5

Jet lag

Answer 5

stems from mismatch of circadian clock, and external cues

Question 6

Mechanisms of the biological clock include:

Answer 6

Suprachiasmatic nucleus (SCN), Genes that produce certain proteins, Melatonin levels (neurotransmitter)

Question 7

Suprachiasmatic Nucleus (scn)

Answer 7

Part of the thalamus, main control centre of circadian rhythms of sleep and temperature, located above the optic chiasm.

Question 8

Neurons in the SCN respond to light through the …

Answer 8

Retinohypothalamic path

Question 9

There are two types of genes that are important for circadian rhythms. Period and Timeless. They produce genes called …

Answer 9

PER and TIM. Oscillate. Low during day and high during night. Promote sleep and inactivity.

Question 10

The Pineal gland

Answer 10

secretes melatonin to increase sleepiness, located posterior to the thalamus, controlled by the SCN.

Question 11

Sleep is a state that the brain actively/passively produces

Answer 11

actively

Question 12

Electroencephalography (EEG) revealed…

Answer 12

that sleep occurs in stages.

Question 13

Relaxed, awake

Answer 13

Alpha waves, 8-12 Hz

Question 14

Stage 1 sleep

Answer 14

irregular, jagged, low voltage waves. Desynchronized neural activity.

Question 15

Stage 2 sleep

Answer 15

Sleep spindles (bursts of 12-14 Hz activity - 1/2 second), K-complexes (sharp decrease in activity, followed by sharp increase).

Question 16

Stage 3 & 4

Answer 16

Slow wave sleep (SWS). Slow, large waves. Highly synchronized neural activity. Slow heart rate and breathing rate. 4 More common earlier in the night.

Question 17

REM - Rapid eye movement

Answer 17

Paradoxical, with characteristics of light and deep sleep. More common later in the night.

Question 18

Reticular Formation

Answer 18

Part of the midbrain that extends from the medulla to the forebrain. Responsible for arousal.

Question 19

Pontomesencephalon

Answer 19

Part of the reticular formation. Axons extend to the hypothalamus, thalamus, and basal forebrain (acetylcholine, glutamate). Maintains and increases arousal.

Question 20

Locus Coeruleus

Answer 20

Small structure in the pons. Axons release norepinephrine to arouse various areas of the cortex and increase wakefulness. Dormant while asleep.

Question 21

Hypothalamus

Answer 21

Releases neurotransmitter Orexin. Stimulates acetylcholine releasing cells in the basal forebrain. Excitatory projections to thalamus and cortex.

Question 22

In sleep, cells of the basal forebrain release the inhibitory neurotransmitter…

Answer 22

GABA, which is inhibitory. It decreases body temp, metabolic rate, and stimulation of neurone throughout the brain.

Question 23

Insomnia

Answer 23

Sleep disorder associated with inadequate sleep

Question 24

Phase delay

Answer 24

results in difficulty getting to sleep

Question 25

Phase advance

Answer 25

results in difficulty staying asleep

Question 26

Sleep apnea

Answer 26

Inability to breathe while sleeping for long periods of time. Caused by genetics, hormones, old age, obesity

Question 27

Narcolepsy

Answer 27

Frequent periods of sleepiness. Sudden attacks of sleep, sometimes cataplexy, sleep paralysis, hypnagogic hallucinations. Produced by lack of hypothalamic cells that produce and release orexin.

Question 28

Cataplexy

Answer 28

sudden weakness of muscles triggered by strong emotions

Question 29

Sleep paralysis

Answer 29

inability to move while falling asleep or waking up

Question 30

Hypnagogic hallucinations

Answer 30

dreamlike experiences

Question 31

Functions of sleep

Answer 31

Energy conservation, restoration of the brain and body, memory consolidation

Question 32

Energy conservation is achieved by

Answer 32

decreasing body temperature and muscle activity. Animals increase sleep time during food shortages.

Question 33

Sleep enhancing learning

Answer 33

activity in hippocampus similar to learning, brain strengthens some synapses and weakens others.