Sleep-wake cycle an menstrual cycle are maintained by

Options

A. Progesterone
B. Melatonin
C. Oxytocin
D. MSH

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the hormones that maintain the sleep-wake cycle and the menstrual cycle.

2. **Identifying the Sleep-Wake Cycle**: The sleep-wake cycle, also known as the circadian rhythm, is primarily regulated by the hormone melatonin.

3. **Source of Melatonin**: Melatonin is secreted from the pineal gland, which is located in the brain. This hormone helps to regulate sleep patterns by signaling to the body when it is time to sleep.

4. **Identifying the Menstrual Cycle**: The menstrual cycle in females is regulated by several hormones, including estrogen and progesterone. However, the question specifically asks for the hormone that maintains both cycles.

5. **Evaluating the Options**:
- **Option 1: Progesterone** - This hormone is primarily involved in maintaining pregnancy and regulating the menstrual cycle but does not regulate the sleep-wake cycle.
- **Option 2: Melatonin** - This is the correct answer as it regulates the sleep-wake cycle.
- **Option 3: Oxytocin** - This hormone is involved in childbirth and lactation, not in regulating either cycle.
- **Option 4: Melanocyte-stimulating hormone** - This hormone is related to skin pigmentation and does not play a role in either cycle.

6. **Conclusion**: Based on the evaluation of the options, the hormone that maintains the sleep-wake cycle is melatonin, making Option 2 the correct answer.

**Final Answer**: The sleep-wake cycle is maintained by melatonin, which is secreted from the pineal gland.

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