Lymphnode
Definition
o Lymph nodes are collections of lymphoid tissue at strategic points
o Small and medium sized lymph vessels open into lmph nodes
o The lymph runs through 8 - 10 nodes before reaching the blood stream
Structure
o Capsule - fibrous tissue - forms trabeculae (partitions)
o Substance of the lymph node is made of
reticular tissue & lymphatic tissue - containing many lymphocytes and macrophages
o 4 - 5 afferent lymph vessels enter the lymph node
o One efferent lymph vessel carries lymph away from the node
o Lymph node has - hilum - a concave part through which an artery enters and a vein and efferent lymph vessel leave
Nodes for different regions
o For head & neck - deep and superficial cervical nodes
o Upper limbs - nodes in the elbow regions - deep and superficial axillary nodes
o Lower limbs - deep ad superficial nodes including popliteal nodes and inguinal nodes
o Breast - axillary nodes
o Thoracic cavity - parasternal, intercostal, brachiocepalic, mediastinal, tracheobronchial, bronchopulmonary and eosophageal nodes
o Pelvic and abdominal cavities - nodes associated with the blood vessels supplying the organs and close to the main arteries i.e. The aorta and external and internal iliac arteries.
Functions of Lymph Nodes
o Filtering bacteria and other particulate matter
o phagocytosis
o Proliferation of lymphocyteso
o Activated T and B lymphocytes multiply in lymph nodes
o Antibodies are produced by sensitised B-lymphocytes
o The antibodies enter lymph and blood from the node
