What are the structures on which progesterone acts?

Options

A. Uterus
B. Mammary glands
C. Cervix
D. All of the above

Answer

To answer the question about the structures on which progesterone acts, we will analyze the roles of progesterone in the female reproductive system.

### Step-by-Step Solution:

1. **Understanding Progesterone**: Progesterone is a steroid hormone primarily produced by the ovaries after ovulation. It plays a crucial role in the menstrual cycle and in maintaining the early stages of pregnancy.

2. **Identifying Target Structures**:
- **Uterus**: Progesterone prepares the endometrium (the lining of the uterus) for potential implantation of an embryo. It helps maintain the uterine environment conducive to pregnancy.
- **Mammary Glands**: Progesterone contributes to the development of mammary glands during puberty and prepares them for milk production during pregnancy and lactation.
- **Cervix**: Progesterone influences the cervical mucus, making it thicker, which helps to prevent sperm from entering the uterus during certain phases of the menstrual cycle.

3. **Conclusion**: Based on the functions of progesterone, it acts on the following structures:
- Uterus
- Mammary Glands
- Cervix

Thus, the correct answer is that progesterone acts on all of the above structures.