Thoracic duct opens into

Options

A. right subclavian artery
B. left subclavian artery
C. right subclavian artery
D. left subclavian vein

Answer

**Step-by-Step Solution:**

1. **Understanding the Thoracic Duct**: The thoracic duct is the largest lymphatic vessel in the human body. It plays a crucial role in the lymphatic system by transporting lymph, which is a fluid that contains excess fluids, proteins, and waste products from tissues back into the bloodstream.

2. **Function of the Thoracic Duct**: The thoracic duct is responsible for transporting approximately 75% of the lymph from the entire body. It helps maintain fluid balance by returning excess interstitial fluid to the circulatory system.

3. **Location of the Thoracic Duct**: The thoracic duct primarily drains lymph from the left side of the body, including the left arm, left side of the head and neck, and the entire lower body.

4. **Opening of the Thoracic Duct**: The thoracic duct opens into the left subclavian vein. This is where the lymph collected by the thoracic duct is returned to the bloodstream.

5. **Comparison with Right Lymphatic Duct**: It is important to note that the right side of the body has a different lymphatic vessel known as the right lymphatic duct, which drains lymph from the right side of the head, neck, and right arm into the right subclavian vein.

6. **Conclusion**: Therefore, the thoracic duct opens into the left subclavian vein, making this the correct answer to the question.

**Final Answer**: The thoracic duct opens into the left subclavian vein.

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