What constitutes the parenchyme of a lymph node?

• A. One outer cortex, one inner cortex, and one medulla
• B. Outer capsule and connective tissue
• C. Only the outer cortex
• D. Medullary cords and sinuses

Answer: (A)

The parenchyme of a lymph node refers to the functional tissue that performs the essential roles of the lymph node, primarily in immune response. It consists of the outer cortex, which contains lymphoid follicles rich in B cells, and the inner cortex, mainly populated by T cells, along with the medulla, which contains medullary cords that produce and house both T and B lymphocytes.

This structure allows the lymph node to effectively filter lymph fluid and facilitate the activation and proliferation of lymphocytes in response to pathogens. The arrangement of the outer and inner cortex along with the medulla is crucial for organizing the varied immune functions within the node.

The other options listed do not fully encompass the functional components that constitute the parenchyme. For example, the outer capsule and connective tissue serve more to support the node structurally rather than contributing directly to its functional immune processes. Therefore, the comprehensive definition of the parenchyme encompasses all three regions - the outer cortex, inner cortex, and medulla.