LYMPHATIC SYSTEM

1. LYMPHATIC SYSTEM HS-ATS-8

2. OBJECTIVES • Explain the function of lymphatic vessels • List at least two functions of lymph nodes • Identify the 2 lymphatic ducts and the areas of the body that each drains • List at least 3 functions of the spleen • Describe the function of the thymus • Describe at least 3 diseases of the lymphatic system

3. What happens to the “glands” in your neck when you have a sore throat or bad cold? • Why does this happen?

4. Introduction • Lymphatic system consists of lymph, lymph vessels, lymph nodes, and lymph tissue • Works with the circulatory system • Removes waste and excess fluid from tissues

5. Lymphatic System

7. Lymph • Thin, watery fluid • Composed of intercellular or interstitial fluid that forms when plasma diffuses into tissue spaces • Composed of water, digested nutrients, salts, hormones, oxygen, carbon dioxide, lymphocytes, and metabolic wastes such as urea • When fluid enters lymphatic system, it becomes known as lymph

8. Lymphatic Vessels • Located throughout the body in almost all tissues that have blood vessels • Lymphatic capillaries • Small, open-ended lymph vessels • Act like drainpipes • Pick up lymph at tissues throughout the body • Capillaries join together to form larger lymphatic vessels

9. Lymphatic Vessels • They carry lymph • Contractions of skeletal muscles against lymph vessels cause lymph to flow through vessels • Vessels pass through lymph nodes • Contain valves that keep lymph flowing one way

10. Lymphatic Vessels • Specialized lymphatic capillaries, called lacteals, located in area of small intestine • Pick up digested fats, or lipids • When lymph is mixed with the lipids, it is called chyle • Lacteals transport the chyle to the bloodstream through the thoracic duct

11. Lymph Nodes • Popularly called, “glands” • Located all over the body, usually in groups or clusters • Small, round masses ranging in size from a pinhead to an almond • Lymph vessels bring lymph to nodes • Nodes filter lymph and remove impurities such as: • Carbon • Cancer cells • Pathogens, which are disease-producing organisms • Dead blood cells

12. Lymph Nodes • Lymphatic tissue in nodes also produces substances such as: • Lymphocytes: a type of leukocyte, or WBC • Antibodies: substances used to combat infection • Purified lymph, with lymphocytes and antibodies added, leaves the lymph node by a single lymphatic vessel

14. Lymphatic Ducts • As lymphatic vessels leave the lymph nodes, they continue to join together to form larger lymph vessels • Eventually, they drain into one of two lymphatic ducts: right lymphatic duct or thoracic duct • Right lymphatic duct • Short tube • Receives all purified lymph from right side of head and neck, right chest, and right arm • Empties into right subclavian vein, returning purified lymph to the blood

15. Lymphatic Ducts • Thoracic duct • Much larger tube • Drains lymph from the rest of the body • Empties into left subclavian vein • Enlarged pouch-like structure called the cisternachyliis located at the start of the thoracic duct • Serves as storage area for purified lymph • Receives chyle from intestinal lacteals

16. Lymph Tissue • Located throughout the body in addition to being in lymph nodes • Tonsils, spleen, and thymus are examples of lymphatic tissue • Tonsils • Masses of lymph tissue • Filter interstitial fluid • Three pairs of tonsils • Palatine tonsils on each side of soft palate • Pharyngeal tonsils (also called adenoids) located in nasopharynx (upper part of throat) • Lingualtonsils on back of tongue

17. Spleen • Organ located on left side in back of upper part of stomach • Produces leukocytes and antibodies • Destroys old erythrocytes, or RBC’s • Stores erythrocytes to release into bloodstream if excessive bleeding occurs • Destroys thrombocytes or platelets • Filters some metabolites and wastes from tissues

18. Thymus • Mass of lymph tissue located in center of upper chest • Atrophies, or wastes away, after puberty and is replaced by fat and connective tissue • Functions during early life • Produces antibodies • Manufactures lymphocytes to fight infection • Function is taken over by lymph nodes after it atrophies

19. Adenitis • Inflammation or infection of lymph nodes or glands • Occurs when pathogens or cancer cells enter nodes and infect the tissue • Symptoms: swollen painful nodes and fever • Abscess may form in node if infection is not treated • Treatment: antibiotics and warm, moist compresses

20. Adenitis

21. Hodgkin’s Disease • Chronic malignant disease of lymph nodes • Most common form of lymphoma (tumor of lymph tissue) • Symptoms • Painless swelling of lymph nodes • Fever and night sweats • Weight loss • Fatigue • Pruritus or itching • Treatment: chemotherapy and radiation

22. Lymphangitis • Inflammation of lymphatic vessels • Usually occurs from infection in an extremity • Symptoms • Red streak extending up from source of infection • Fever and chills • Tenderness or pain • Treatment • Antibiotics for infection • Rest and elevation of affected part • Warm, moist compresses

23. Lymphangitis

24. Splenomegaly • Enlargement of the spleen • Causes: abnormal accumulation of erythrocytes, mononucleosis, and cirrhosis of the liver • Symptoms: swelling and abdominal pain • Increased destruction of blood cells can lead to anemia, leukopenia, and thrombocytopenia • If spleen ruptures, intraperitoneal hemorrhage and shock can lead to death • Splenectomy done in severe cases

25. Splenomegaly

26. Tonsillitis • Inflammation or infection of the tonsils • Usually involves the pharyngeal (adenoid) and palatine tonsils • Symptoms • Throat pain and fever • Dysphagia or difficulty swallowing • White or yellow spots of exudate on tonsils • Swollen lymph nodes by the mandible • Treatment • Antibiotics and analgesics for pain • Warm throat irrigations • Rest and fluids • Tonsillectomy in chronic cases

27. Tonsillitis