1. LYMPHATIC SYSTEM Chapter 9 -3

2. LYMPHATIC SYSTEM LYMPH – Excess tissue fluid and fluid from lymph vessels that doesn’t re-enter capillaries of the body – Rich in white blood cells, protein, and water (~plasma) and is circulated through the body by the lymphatic vessels

4. Organs of lymphatic system: Lymph nodes/ glands Spleen Tonsils Thymus

5. LYMPH VESSELS Structure resembles veins as they have valves to prevent backflow Lymphatic capillaries > lymphatic vessels Collect lymph and carry it toward the heart via the THORACIC DUCT which will eventually empty into the subclavian veins

7. LYMPH NODES/GLANDS Enclosed in fibrous capsules Named for their location (cervical) in the body (vary in size) Act as filters: bacteria, foreign particles, malignant cells Soldiers

8. Palpable/Superficial LN: 5

10. LN Infection Painful and swollen = acute reaction Swollen and nonpainful = chronic reaction

11. SPLEEN Largest structure of lymphoid system Large, flattened, oval-shaped organ that is dark red/black in color Located caudal to the stomach Enlarges with infectious disease FUNCTIONS: HEMATOPOIESIS – forms lymphocytes, monocytes, plasma cells PHAGOCYTOSIS – removes and destroys microorganisms, bad platelets, old RBCs (recycles globin and heme) Stores blood

12. TONSILS 3 pair Masses of lymphoid tissue Palatine, lingual, pharyngeal Differ from lymph nodes as they are near moist surfaces and are located at the beginning of lymph drainage

13. THYMUS Structure of lymph tissue located cranial to the heart Part of the immune system – produces lymphocytes Largest in young animals, atrophies over time