IMMUNOLOGY

Detailed explanation-1: -A 5-year-old child falls and scratches herself and within a few days has an enlarged lymph node in the area draining the abrasion. The cells in the lymph node are reacting to the foreign stimulus that entered the skin and that was transported to the lymph node by which of the following? via high endothelial venules.

Detailed explanation-2: -During steady state, lymph nodes maintain peripheral tolerance. Upon activation, lymph nodes quickly initiate protective adaptive immunity to produce antibody, cytotoxic immune cells and memory against the invading foreign antigens.

Detailed explanation-3: -The lymphatic fluid is supplied to the nodes and the structures of the lymphatic system, where macrophages, and lymphocytes (white blood cells) trigger the immune system to release antibodies against antigens such as viruses, bacteria, and even cancer cells.