Gland which is responsible for rhythms of sleep wake cycle

Answer

**Step-by-Step Solution:**

1. **Identify the Hormone**: The hormone that regulates the sleep-wake cycle is called melatonin.

2. **Locate the Gland**: Melatonin is secreted by a specific gland in the body. This gland is known as the pineal gland.

3. **Understand the Function**: The pineal gland is located in the brain, specifically just above the optic chiasma. It plays a crucial role in regulating the body's circadian rhythms, which include the sleep-wake cycle.

4. **Mechanism of Action**: The melatonin receptors present in the brain respond to the levels of melatonin, helping to synchronize the body's internal clock with the external environment, particularly the day-night cycle.

5. **Conclusion**: Therefore, the gland responsible for the rhythms of the sleep-wake cycle is the pineal gland, as it secretes melatonin.

**Final Answer**: The gland responsible for the rhythms of the sleep-wake cycle is the pineal gland.

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