Lymphatic system

Anatomy & physiology of lymphatic system & components of lymphatic system.

1. Prepared by Ms. Nisha S. Mhaske M.Pharm (Q.A.T) Lecturer, PRES’s COPD, Chincholi. Email : [email protected] Lymphatic system Loknete Dr.Balasaheb Vikhe Patil ( Padmabhushan Awardee ) Pravara Rural Education Society’s College of Pharmacy (D.Pharm) Nashik.

2. Contents Lymph Lymphatic duct Components of lymphatic duct Lymphatic vessels Lymph node Spleen Thymus gland Tonsils Applied anatomy

3. What is lymph ??????? Tissue fluid, when enters to the lymph capillaries, from the tissue spaces is called as the lymph. Lymph is clear, colorless body fluid derived from & closely resembling to the blood. The fluid within the lymph capillaries & vessels is known as lymph.

4. lymphatic capillary lymphatic trunks lymphatic collecting vessels lymphatic ducts Lymphatic vessels start with lymphatic capillaries

5. Lymphatic capillary

6. Special lymph capillaries --- Lacteals Lacteals- lymphatic vessels of the small intestine which absorb digested food. collect digested fats ( in chylomicrons ) Chylomicrons - are lipoprotein particles that consist of Triglycerides, phospholipids, cholesterol & proteins. They transport dietary lipid from the intestine to other locations of the body.

7. Lymphatic duct Tissue fluid, when enters the lymph capillaries is known as lymph. The lymph capillaries unite to form larger vessels which eventually converted into two large ducts Thoracic duct Right lymphatic duct. These ducts drain their lymph or fluid into the left & right innominate veins respectively.

8. Components of lymphatic system Lymph vessels Lymph nodes & other lymphatic tissue Spleen Thymus gland Tonsils

9. Lymphatic vessels Larger ones composed of 3 layers tunica interna: endothelium and valves tunica media: elastic fibers, smooth muscle tunica externa: thin outer layer Valves are present to prevent backflow .

10. Lymph nodes The lymph nodes are the oval or bean or kidney shaped bodies. They are located in the passage of lymphatic vessels. They usually occurs in groups. The concave border of the gland is called as hilum. Efferent lymphatic vessels carries lymph from the lymph node. Afferent lymphatic vessels enters lymph into the gland. After entering the lymph gets filtered in lymph node by trapping of foreign particles & micro-organism. Lymph reaches to blood only after passing through lymph node. There are many groups of lymph nodes in the body such as, neck, axilla, thorax, abdomen & grain. FUNCTIONS Production of lymphocytes and antibodies. They acts as a filter & prevents spread of organism.

11. Spleen Largest lymphatic organ Located to the left of the stomach below the diaphragm under 9 th ,10 th & 11 th ribs. It is 12 cm long, 8 cm broad & 3 cm in thick, wighing 150 gm in adult. It is surrounded by kidney, colon, & pancreas. Histology Red pulp contains all the components of circulating blood White pulp is similar to lymphatic nodules Spleen is covered with persitonium . Below this,is the layer of connective tissue capsules, fibroelastic capsules, that dips into organ,forming trabeculae. The cellular element, consisting of lymphocytes & macrophages, is called splenic pulp. It lies between trabeculae. It consists of spleen artery, spleen vein, lymph vessels & nerves. Blood passing through the spleen passes through sinusoids, instead of capillaries, allowing it to come in contact with splenic pulp.

12. Figure 20.6a,b Arterioles and capillaries Capsule Trabecula Venous sinuses Red pulp Splenic cords White pulp Central artery Splenic artery Splenic vein (b) Diagram of spleen histology Splenic artery Splenic vein Hilum (a) Diagram of the spleen, anterior view

13. Figure 20.6c (c) Photograph of the spleen in its normal position in the abdominal cavity, anterior view. Diaphragm Spleen Adrenal gland Splenic artery Pancreas Left kidney

14. Functions of spleen Phagocytosis Erythrocytes are destroyed in spleen, other cellular materials such as leukocyte, platelets and microbes are also phagocytosed in the spleen. Haemopoietic organ Erythrocytes are formed by spleen in fetal as well as in adult. Red cell storage During stress, it can liberate 150 ml of blood, since it acts as reservoir of red blood cells. Antibodies formation The spleen provides defense against infection by tubercle bacillus.

15. Thymus Location – behind the sternum in the mediastinum The capsule divides it into 2 lobes Development Infant – conspicuous Puberty – maximum size Maturity – decreases in size At birth, gland is small increases in size till puberty and shrinks again the thymus is concerned with antibodies production. Function secretes hormones ( thymopoietin , thymulin and thymosins ) It also controls the lymphocyte production by spleen & other spleen glands. In elderly mostly fatty and fibrous tissue

16. Tonsils Multiple groups of large lymphatic nodules Location – mucous membrane of the oral and pharyngeal cavities Palatine tonsils Posterior-lateral walls of the oropharynx Pharyngeal tonsil Posterior wall of nasopharynx Lingual tonsils Base of tongue

17. Functions of lymphatic system To return the tissue fluid to the general circulation Transportation of lymphocytes from lymph glands to the circulation The lymph nodes filter & destroy the microorganisms thereby preventing the spread of the infection. Antibody formation by the lymph glands for protection of the body.

18. Derivation and Distribution of Lymphocytes

19. References Human Anatomy & Physiology, by Rahul Phate , Career publications, First edition-Jan 2004, Page no:67-71. Human Anatomy & Physiology, by S.B.Bhise & A.V.Yadav , Nirali Prakashan , 25 th edition-July 2013, Page no:6.1-6.3

20. Applied anatomy Lymphangitis --- Inflammation of the lymph vessels Lymphedema --- Occurs due to accumulation of lymphatic fluid in the interstitial tissue

21. Lymphadenopathy --- Means a disease of the lymph nodes Lymph nodes become swollen/ enlarged and may be painful to touch Lymphomas --- Cancers originating either from the lymphocytes in the lymph nodes or the lymphatic tissue in organs Risk factors -- HIV, Hepatitis.

22. Tonsillitis--- Infection of the pharyngeal tonsils Tonsils are swollen, Fever and pain during swallowing usually present Treatment – surgical removal of tonsils ( Tonsillectomy) Splenomegaly --- Enlarged Spleen