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31 Cards in this Set
- Front
- Back
Define Endogenous Circannual Rhythms ; |
Internal mechanisms that operate on an annual (yearly) cycle. |
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Describe Endogenous ; |
From within. |
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Describe Circannual ; |
About yearly. |
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What do all animals produce? |
Endogenous Circadian Rhythms. |
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Define Endogenous Circadian Rhythms ; |
Internal mechanisms that operate on a 24 hour cycle. |
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What do these 24 hour circadian rhythms regulate? |
Regulates wakefulness and sleep as well as many other behaviors and functions. |
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What are some of the functions of circadian rhythms? |
Frequency of eating and drinking, body temperature, secretion of hormones, urination, and sensitivity to drugs. |
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Cycle differ between? |
Differ between people and lead to different patterns of wakefulness and alertness. |
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What can identifying your endogenous rhythm for sleep and wakefulness help you identify? |
Your best time to study and sleep. |
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Your endogenous rhythm changes as function of? |
Age. |
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What is the purpose of the circadian rhythm? |
Is to keep our internal workings in phase with the outside world. |
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When the human circadian clock has no external cue to set, what happens to it? |
It generates a rhythm slightly longer than 224 hours. |
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What establishes our circadian rhythm? |
An internal biological clock. |
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Define Zeitgeber ; |
German meaning "time giver", refers to stimuli that reset the circadian rhythm. |
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Examples of Zeitgeber ; |
- Sunlight (primary zeitgeber), exercise, meals, arousal of any kind, temperature. - Depression, irritability, and impaired job performances are effects of using something other than sunlight as a zeitgeber. |
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Define Jet Lag ; |
Refers to the disruption of the circadian rhythms due to crossing time zones. |
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Examples of Jet Lag ; |
- Stems from a mismatch of the internal circadian clock and external time. - Results in sleepiness during the day, sleeplessness at night, and impaired concentration. |
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When you travel west what happens to our circadian rhythms. |
It Phase-Delays. |
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When you travel east what happens to our circadian rhythms. |
It Phase-Advances. |
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Circadian rhythms remain? |
Consistent despite lack of environmental cues indicating the time of day. |
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Is it difficult to force a change in our circadian rhythm? |
Yes. |
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What fails to reset our biological clock? |
Alarm clocks, raves, and brain damage. |
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What generates our circadian rhythm and what makes it so tough to change? |
- The suprachiasmatic nucleus. - Genes that produce certain proteins. - Melatonin levels. |
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Define the Suprachiasmatic Nucleus (SCN) ; |
Is part of the hypothalamus and the main control center of the circadian rhythms of sleep and temperature regulation. |
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Characteristics of the Suprachiasmatic Nucleus (SCN) ; |
- Located above the optic chiasm / part of the hypothalamus. - Damage to the SCN results in less consistent body rhythms that are no longer synchronized to environmental patters of light and dark. |
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What does the SCN generate? |
Generates the circadian rhythms in a genetically controlled, unlearned manner. |
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What does a single cell extracted from the SCN and raised in tissue culture continue to produce? |
Produces action potentials in a circadian rhythmic pattern. |
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What did a mutation in one gene cause on hamsters? |
Caused SCN to produce a 20-hour rhythm. |
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What does Light do to the SCN. |
Light resets the SCN via. a small branch of the optic nerve known as the retinohypothalamic path that travels directly from the retina to the SCN. |
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Define Retinohypothalamic Path ; |
A small branch of the optic nerve. |
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The retinohypothalamic path comes from? |
A special group of ganglion cells that have their own photopigment called melanopsin. |