Which of the following secretes the hormone responsible for relaxing pubic symphysis during the childbirth ?

Options

A. Pineal gland
B. Macula
C. Corpus albicans
D. Placenta

Answer

To solve the question "Which of the following secretes the hormone responsible for relaxing pubic symphysis during childbirth?", we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Question**: We need to identify which gland or organ releases the hormone that relaxes the pubic symphysis during childbirth.

2. **Identify the Options**: The options provided are:
- A) Pineal gland
- B) Macula
- C) Corpus albicans
- D) Placenta

3. **Analyze Each Option**:
- **Pineal Gland**: This gland is primarily responsible for the secretion of melatonin, which regulates sleep-wake cycles. It does not play a role in childbirth or the relaxation of the pubic symphysis.
- **Macula**: This term typically refers to a part of the eye or a structure in the kidney, and it is not related to hormone secretion during childbirth.
- **Corpus Albicans**: This structure is formed from the degeneration of the corpus luteum after ovulation. While the corpus luteum does secrete relaxin in small amounts, it is not the primary source during childbirth.
- **Placenta**: The placenta is an organ that develops during pregnancy and is responsible for many hormonal functions. It secretes relaxin in large quantities during childbirth, which helps to relax the pubic symphysis and widen the birth canal.

4. **Conclusion**: Based on the analysis, the correct answer is **D) Placenta**. The placenta secretes relaxin, which is crucial for relaxing the pubic symphysis during childbirth.

### Final Answer:
**D) Placenta**

---