Anatomy Practice Exam

Which system includes a network of vessels that runs alongside circulatory vessels?

1. Nervous system

2. Muscular system

3. Lymphatic system

4. Endocrine system

The correct answer is: Lymphatic system

The lymphatic system is a network of vessels that runs alongside circulatory vessels, playing a crucial role in the body's immune response and fluid balance. This system is composed of lymphatic vessels, lymph nodes, and lymphoid organs, which work together to transport lymph – a clear fluid that contains white blood cells, proteins, and fats – from tissues back into the circulatory system. One of the primary functions of the lymphatic system is to maintain fluid homeostasis by collecting excess interstitial fluid that leaks from blood capillaries and returning it to the bloodstream. Additionally, by filtering out pathogens and foreign substances through lymph nodes, the lymphatic system helps to protect the body from infections and diseases. In contrast, the other systems listed do not have a network of vessels that parallels the circulatory vessels. The nervous system primarily consists of the brain, spinal cord, and nerves; the muscular system involves muscle tissues and structures related to movement; and the endocrine system comprises glands that secrete hormones into the bloodstream. Therefore, the lymphatic system’s unique relationship with vascular structures sets it apart as the correct answer.