Macrophages are found scattered within the lymphoid tissue. They are, once again, difficult to distinguish from the reticular cells. Blood Vessels Blood vessels enter the lymph nodes through the hilus and travel initially in the connective tissue trabeculae that extend from the hilus into the parenchyma of the lymph node. They continue in the medullary cords towards the cortex and give off capillaries to the surrounding tissue as they do so. Lymphocytes, which reach the lymph node via the blood stream, may migrate through this epithelium as part of their recirculation.
Larger venules accompany the arteriolar branches as they leave the lymph nodes.
Identify the connective tissue capsule and trabeculae, cortex and medulla of the lymph node, lymph nodules with germinal centres, medullary cords and postcapillary venules. Include, if possible, a postcapillary venule at high magnification. Note that most of them are located in the paracortex and medulla.