The immune system consists of a complex network of organs, cells, and molecules that work together to defend the body from pathogens. The primary lymphoid organs, bone marrow and thymus, produce immune cells. The secondary lymphoid organs, including lymph nodes and spleen, contain specialized compartments where immune cells gather and respond to antigens. Immune cells travel between the blood, lymph, and lymphoid tissues to carry out functions like pathogen recognition and elimination.

1. Presented by Dr.B.Victor St.Xavier's College, Palayamkottai-627002,India. Functional organization of the immune system : 1. Immunogenic Organs

12. Main Types of Immunity in Man Immunity Innate immunity Adaptive immunity Natural Artificial Passive (maternal) Active (Infection) Passive (Serotherapy) Active (Vaccination)

16. Physical and Chemical Defenses

29. Overview of blood and lymph system and how leukocytes travel from one system to another Thoracic duct Site of exchange between the blood and lymph systems Lymph carrying antibodies and immune cells collect in thoracic duct where the lymph empties back into the blood circulatory system

30. Immune cells travel back and forth from the blood and lymph circulatory systems and interact with extra-vascular tissues in the process-- extravasation muscle

31. Lymphatic vessels.

32. The organs of the immune system

34. Kinds of Lymphoid Organs The Lymphoid Organs Primary or Central organs Secondary or Peripheral organs 1.Bone marrow 2.Thymus gland 3.Bursa of fabricius 1.Lymp nodes 2.Spleen 3.Diffuse lymphoid tissues

37. Primary and Secondary Lymphoid organs

48. Lymph Node

54. Spleen

55. Spleen

67. Thank you