The Immune System

1. The Immune System The Anatomy of the Immune System

2. Anatomy of the Immune System • The organs of the immune system are stationed throughout the body. • They are generally referred to as lymphoid organs because they are concerned with the growth of lymphocytes. • Lymphoid organs include the bone marrow and the thymus, as well as lymph nodes, spleen, tonsils and adenoids, the appendix and clumps of lymphoid tissue in the small intestine known as Peyer’s patches.

3. Anatomy of the Immune System

4. Anatomy of the Immune System • BONE MARROW: • Bone marrow is the soft tissue in the hollow shafts of long bones. • Lymphocytes are produced in the bone marrow. • B cells complete their maturation in the bone marrow.

5. Anatomy of the Immune System • THYMUS: • The thymus is an organ that lies high behind the breastbone. • T cells migrate to the thymus, and there they multiply and mature into cells capable of producing an immune response.

6. Anatomy of the Immune System LYMPHATIC VESSELS: • a network of vessels similar to blood vessels. • Upon exiting the bone marrow and thymus, some lymphocytes travel continuously throughout the body; they use the blood circulation system as well as the lymphatic vessels.

7. Anatomy of the Immune System • Upon exiting the bone marrow and thymus, some lymphocytes gather in lymph nodes and immune organs. • Spleen • Tonsils and adenoids • Appendix • Peyer’s patches

8. Anatomy of the Immune System • LYMPH NODES: • Along the lymph vessels are small, bean-shaped lymph nodes. • Each lymph node contains both B and T cells, thus it brings together the components needed to start an immune response.

9. Anatomy of the Immune System • SPLEEN: • a fist-sized organ in the upper left of the abdomen. • The spleen provides a meeting ground for immune defenses. • Synthesizes antibodies • Stores monocytes

10. Anatomy of the Immune System • TONSILS and ADENOIDS: • Tonsils are soft lymphatic tissue in the back of your throat. Adenoids are higher up, behind your nose. • Both help protect you from infection by trapping germs coming in through your mouth and nose.

11. Anatomy of the Immune System • APPENDIX: • Blind-ended pouch near where the small and large intestines meet. Contains lots of lymphatic tissue. • Exact purpose is unknown. May be involved in maintaining helpful bacteria in the gut.

12. Anatomy of the Immune System • PEYER’S PATCHES: • Ovals of lymphatic tissue, similar to lymph nodes, found in the lowest portions of the small intestine. • Monitor the intestinal tract for undesirable microbes and help initiate immune response.