Chapter 1. The Suprachiasmatic Nucleus

Infographic

Infographics Activity
true
true

The suprachiasmatic nucleus (SCN) of the hypothalamus is the body’s internal master clock, playing a role in regulating our circadian rhythms. These rhythms roughly follow the 24-hour cycle of daylight and darkness. But one doesn’t have to consciously perceive light for the SCN to function properly: there is a dedicated, nonvisual pathway that carries light information from the eyes to the SCN.

The figure shows human brain. Reticular formation regulates alertness and sleepiness. Pineal gland produces melatonin. Hypothalamus regulates patterns of hunger and temperature. The Suprachiasmatic nucleus (SCN) is actually two tiny bundles of neurons within the hypothalamus. The SCN sends messages about light to the rest of the hypothalamus and the reticular formation, and regulates the pineal gland’s production of melatonin, a sleep-inducing hormone. The SCN is located deep in the brain, far away from visual processing areas. So how does it get information about light. Our eyes contain a separate nonvisual pathway made of retinal ganglion cells. This pathway goes directly to the SCN. For the 20 percent of the U.S. workforce doing shift work, normal sleep schedules are disrupted. This leads to health problems and increased accidents (Harrington, 2001). Using what we know about how the SCN works, researches are helping industries ease these effects. Bright light, such as those installed in this power station control room, contain a high proportion of the light found in morning sun, fooling the SCN into thinking it is daytime. That makes it easier for workers to synchronize sleep patterns with work activities.

1.1 Quiz

Question

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
Correct.
Incorrect.

1.2 Quiz

Question

EvRXN6wrxieCqGLO9B3Mj+0npQNn2mtFyF1yMlNVZQNjw2IMCCR5K2r+2zc8pJSZmZRuVXds7Evzla5QuAlPL/Chylvg+PfLb78Dg8h5+/bILqrKuQ0sDur2xYhHwwaEmQcucsuQ/nac3G+TPPZDE3emiOpocRfwAE5iMvUfrf0TFq0J9OXvzjmE5BW7+XTb0TLsWwk3LROxTdZ3w9Phm4hovDrYARLcYEf72kbZLVJSI906XlZx2vZ6VZHvd15qI62lXClBgt2zch/ip0pRhQkKVu6IO0aMSNHuyN93nEnogk5El8uRC12luuMwsPEeu6/XPQ==
Correct.
Incorrect.

1.3 Quiz

Question

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
Correct.
Incorrect.

1.4 Quiz

Question

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
Correct.
Incorrect.

1.5 Quiz

Question

ahDjbMTNAQWLe7S2KrVSYLj1bsBG8+Hz24bA5rbYuEOK3HUnhrwGFzuk5Jl8oCI1wXBNuLx6BPKupPC+usqOE/Q5uypivQD7HHE3mk8aUgWItD1c5f8DXuDWgz1Ggd8wRF+DTsWl+mJ5oChDbPW8n88utooyOGMAW9vd2iXA8PUDef+pSnXJwjA0LAZhVOTsO5zyTuSmkzxYvELY7AHGspQ5JwunKq4a0ndzEfxBACmfTp2KcIJQdSDV6rNSTvyF/HP8+UJ+KEJ9Db3mC9nkJRh7OguyQuFnX3dMYRVnpF15oDmaOgL3gMUeFMTYwRfX
Correct.
Incorrect.

1.6 Quiz

Question

UgQyKepGCVjTTjV4jEahCUoPxZ7PmwDZ6IkSkE+Zip3K80To7v1wFE/K69hhMSueZU94NFagxWlt5NL0kj50mdFIMtOdd9MYg6BAIGR0S3QPFXHgV40ZuS3/GD7zOnGFbuOjWrwYBKCYkOq0jJ1XKpQScf+o+G6fu/8STMV3bPRGtxMz+7SKT1LtBRqKSusIYUV90tUWCIav58Yfdt3E1+UzBX8j18Q1AXwGHydPVFku73nZs/9iTIO8npTuRT7nQpB6qjACWG6b/xXLrg/uEkhVxLOzkT+kcV7eUcHhRNqat8raBQQhveGheaUqGZnugkgxQ495wCXqJsI6mLVAWZbO/hMMt2h1YUWJbesjxPWGtdDjQzVxTEj1wYtw3B/rFoo4O4a38Mst3Ax52uJbCeuGMpHEd/58cKWaOtGnQQoq9NnEmDF5Cwk3RMnhqeLjWO5gjasLGFE6PEv2QbUfW/qBWDO4eNYtY4LUJSpwdKditRNgeZQXB9s0baSrNSzg9kMnYdBkPDu++QMZKqtEaO9lSb/KcA/TCJcl2DUF1W23GKG+9KsHJM4RDYt6DHKsFEz/XYw8E0MsTNGnrU5poyMuyXPFHteZ8o1cqIkpoP7tucxUNvp6NQH7hNwm8x9EF2WituyDRDI8CU6yYQBc85VtvrMWpw28fxwjJfhtkCnECsNg4cpH7IHTCk/PvvZvkIYu2wSkqFesb2q3XX+VtS3JgGspCIBiKIUXLKiph0aEOzGUxG9n4ONSsKMxO3y1TjlmaWqBrCVr/lSPh8jnosfc8y6WuUBs41gvVjhQ65I1swBZMlxwQo6tUxeHQhTdDuKgNsjL6CdvPRQGLn/4lXx0zGgoFy7jxbgZLW9crItjWXRCh834E9sEVmm8pxbIUG/fGJnpXOgD56/6h+OJSJZukGCg3G4t11E5yllolcRtCRDb2IXtuhzq0tSTOjxsM71ql2sbXa9TurZFp0h6OJDffSZZ4xR2FN1bqS7sfT4=
Correct.
Incorrect.

Activity results are being submitted...