Quiz 17

24.) In a person who sleeps during the night, when is the secretion of melatonin HIGHEST (approximately)?

3am

33.) What are the symptoms of winter S.A.D.?

Irritability Tiredness or low energy Problems getting along with other people Hypersensitivity to rejection Heavy, "leaden" feeling in the arms or legs Over sleeping Appetite changes, especially a craving for foods high in carbohydrates Weight gain

13.) iPRGs are now thought to be of several different types: M1 type iPRGs project to the __________ to regulate circadian photo-entrainment (what does this term mean?) and to the __________________ to regulate the pupillary constriction reflex.

SCN (the input of light) Olivary Pretectal Nucleus (OPN)

3.) Which behaviors & physiological processes in mammals exhibit circadian rhythmicity?

Sleep Digestive activity Physical activity Alertness Neuronal activity Hormone secretion Body temperature Immune function

15.) The 'Master Biological Clock of the Body' is the _________________________________.

Suprachiasmatic Nucleus (SCN

11.) Which region of the brain is innervated by the axons of iPRGs?

Suprachiasmatic Nucleus(SCN) using the Retino-Hypothalamic Tracts

19.) Where is the Pineal Gland located?

The Pineal Gland is innervated by the SCN, but it lacks direct nervous connections to other parts of the brain. it is in the middle of the brain

1.) What does the word 'circadian' mean?

about a day

5.) What do the words 'diurnal', 'nocturnal' and 'crepuscular' mean?

active during the day active at night active during dawn and dusk

2.) In which types of organisms (on Earth) have circadian rhythms been observed?

animals plants fungi cyanobacteria

12.) What are the Retino-Hypothalamic Tracts? How do they differ from the Optic Tracts?

axons that propagate action potentials from iPRGs to the SCN. The RHT is separate from the OPTIC TRACTS that carry visual information from the retina to the brain.

9.) Which wavelengths (and colors) of light are detected by intrinsically-photosensitive retinal ganglion neurons (iPRGs)?

blue light (466-477)

28.) From which neurotransmitter/hormone/neurohormone is melatonin directly synthesized?

dietary proteins- tryptophan- 5-hydroxytryptophan- serotonin- melatonin

34.) How can night-shift workers most effectively adapt to night shifts?

expose themselves to pure darkness during the day and bright blue light during the night

32.) How can S.A.D. be avoided, or treated?

exposing eyes to natural or artificial blue light

16.) In which region of the brain are the Suprachiasmatic Nuclei (SCN) located?

hypothalamus

10.) What is the MELANOPSIN, what does it do, and how is it related to iPRGs?

iPRGs contain this A photo sensitive G protein that absorbs blue light

20.) Where are the Superior Cervical Ganglia located?

in the neck

6.) What do the words "endogenous", "intrinsic", "entrained" and "Zeitgeber" mean?

inherent to our bodies synchronized time giver

23.) How is the secretion of MELATONIN affected by exposing the retinas to blue light?

it is stopped

18.) If the SCN are destroyed, what happens to the animal's circadian rhythms?

its gone

27.) From which amino acid is melatonin synthesized?

l-tryptophan

7.) What is meant by 'the dual nature of light'?

light can act as a particle and a wave

22.) What does the word 'Pleiotropic' mean?

multiple effects from a single gene

17.) Neurons within the SCN exhibit ________________ activity.

pacemaking

21.) What is MELATONIN? Which organ secretes it?

pineal glad secretes it and it is the "hormone of darkness"

30.) What is S.A.D.?

seasonal affective disorder

31.) What causes S.A.D.?

secretion of melatonin during the day

14.) The neurons that directly innervate the Pineal Gland have their cell bodies (somata) located in the ____________ ___________ ______________.

superior cervical ganglion cells

26.) What happens to melatonin secretion as you get older (above 65 years of age)?

the amount secreted decreases

8.) Approximately which range of wavelengths of electromagnetic radiation are considered by humans to be 'light'?

visible light

25.) Does your pineal gland secrete more melatonin during the summer when the days are long, or during the winter when the days are short?

winter

29.) Does melatonin affect the secretion of hormones by the Pituitary Gland?

yes

4.) How does body temperature vary during the day and night?

your body temperature rises during the day and falls at night