match the following terms with the correct description.
A. afferent lymphatic vessels
B. efferent lymphatic vessel
C. germinal center
D. medullary sinus E. trabecular sinus
The correct answer and explanation is:
Correct Matching of Terms with Descriptions:
- A. Afferent lymphatic vessels – Bring lymph into the lymph node from peripheral tissues
- B. Efferent lymphatic vessel – Carries lymph out of the lymph node at the hilum
- C. Germinal center – Site within a lymph node where B lymphocytes proliferate and differentiate
- D. Medullary sinus – Network of spaces in the medulla of a lymph node where lymph collects before exiting
- E. Trabecular sinus – Channel that runs along the trabeculae and directs lymph from the subcapsular sinus toward the medulla
Explanation:
Lymph nodes are small, bean-shaped structures that are critical in the immune system. They filter lymph, a fluid that carries white blood cells and debris from tissues. Lymph enters the node through afferent lymphatic vessels. These vessels pierce the lymph node capsule and empty lymph into the subcapsular sinus, after which it flows into the trabecular sinuses. These sinuses run alongside connective tissue structures called trabeculae, guiding lymph deeper into the node.
Within the lymph node cortex, germinal centers are found in lymphoid follicles. These centers are crucial for the immune response, as this is where B cells rapidly divide and mutate their antibody genes to enhance pathogen recognition. These regions are important for adaptive immunity and are activated during infections or immune challenges.
As lymph continues to move inward, it reaches the medullary sinus in the inner part of the node. This area collects lymph and facilitates the exposure of antigens to immune cells like macrophages and plasma cells. The filtered lymph then exits the node through the efferent lymphatic vessel, which is located at the hilum of the lymph node. This flow ensures continuous surveillance and filtration of lymph as it moves toward larger lymphatic vessels and eventually rejoins the circulatory system.