superchiastmatic response

Question 2

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Answer 2

daylight acts by stimulating light sensitive neurons in the eyes (retina) which then sends neural messages to the suprachiasmatic nucleus. When light is detected, the suprachiasmatic nucleus sends inhibitory messages to the pineal gland, whereas when no light is detected, the suprachiasmatic nucleus sends excitatory neural messages to the pineal gland. Students should then understand that when the pineal gland receives excitatory neural messages from the SCN, the pineal gland produces and releases melatonin through the bloodstream and, as a consequence, induces drowsiness/sleepiness and decreases alertness