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EXAM 4 Nov 28

Terms in this set (30)

Approximately how long does a circadian rhythm last?
About a day, 24 hours
Which mammalian behaviors & physiological processes vary during the day & night?
Sleep, physical activity, alertness, hormone secretion, body temp, immune function, neuronal activity.
Dinurnal, Nocturnal, Crepuscular:
Di: active during the day
Noc: active at night
Crepuscular: night or day
What do the words "endogenous" and "intrinsic" mean?
Endogenous means that something is inherent or built in.
Intrinsic means belonging naturally/essentially
What range of wavelengths (in nanometers) do humans consider to be 'visible light'? What kind of radiation is light?
400-700nm
light is electromagnetic radiation
Which wavelengths (and colors) of light are detected by intrinsically-photosensitive retinal ganglion neurons (iPRGs)?
iPRGs detect blue light
Wavelengths: 446-477nm
NOT thought to be involved in vision
What is the OPSIN (a GPCR with a covalently-attached chromophore) found within iPRGs called?
Melanopsin; detects daylight, and activated by blue light. Similar to rhodopsin.
Which region of the brain is innervated by axons of iPRGs?
Pineal Gland
What are the Retino-Hypothalamic Tracts? How do they differ from the Optic Tracts?
Retino-Hypothalamic tracts: composed of axons that propagate their action potentials from iPRGs to SNC.

Optic Tracts: carry visual information from the retina to the brain. (Rods and cones use the optic tracts to send axons to visual cortex).
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.
M1 type project to the SNC for circadian photo-entrainment. Which means: The entrainment of an organism's circadian rhythm to the pattern of light and dark in its environment.

And to the Olivary Pretectal Nucleus to regulate pupillary constriction reflex.
The neurons that directly innervate the Pineal Gland have their cell bodies (somata) located in the ____________ ___________ ______________.
Superior Cervical Ganglia
The 'Master Clock of the Body' is the
Suprchiasmatic Nuclei/SCN
In which region of the brain are the Suprachiasmatic Nuclei located?
Hypothalamus (paired nuclei within)
Where is the Pineal Gland located?
Roof of third ventricle of brain. Also known as epiphysis.

Secretes melatonin.
What is the difference between melanopsin and melatonin?
Melatonin is hormone secreted by pineal gland at night.

Melanopsin is found in iPRGs, detects presence of daylight.
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