Lymphatic System Lecture Notes PDF

(005) LYMPHATIC SYSTEM PART 1 DR. VIVENCIO REFUERZO| 01/25/21...

(005) LYMPHATIC SYSTEM PART 1 DR. VIVENCIO REFUERZO| 01/25/21 OUTLINE ligands and receptors. In particular, VEGF-D and VEGF-C react with VEGF-3 (Figure 1). They are primarily expressed I. HISTORY in lymphatic endothelium and are responsible for II. DEVELOPEMNT proliferation migration, lymphangiogenesis, and III. CONGENITAL MALFORMATION vasculogenesis. IV. OVERVIEW OF THE LYMPHATIC SYTEM V. GENERAL FUNCTION  Begins at 6th week by the formation of jugular lymph sac, VI. LYMPH followed by cisterna chyli (8th week) and thoracic duct (9th VII. LYMPH MOVEMENT week). VIII. COMPONENTS OF LYMPHATIC SYSTEM IX. 2 MAJOR LYMPHATIC DUCTS X. LYPHATIC SYSTEM XI. LYMPH FLOW XII. MAJOR ACCESORRY OF LYMPH ORGANS XIII. TONSILS XIV. CLINICAL APLLICATION: TONSILITIS XV. SPLEEN XVI. CLINICAL APPLICATION: SPLENOMEGALY XVII. THYAMUS XVIII. LACTEALS XIX. LYMPHATIC SYSTEM OF THE ABDOMEN XX. LYMPH DRANAGE XXI. DISEASES OF LYMPHATIC SYSTEM XXII. CLINCAL IMPORTANCE OF NODES XXIII. TEST YOURSELF I.HISTORY  Integral part of the immune and circulatory system. Connection to immune system: Your lymphatic system is consisted of lymphatic tissues, tonsils, spleen, thymus, and red bone marrow, which produces b cells (produce antibodies) and t cells for immunity. Connection to circulatory system: ~15% in the interstitial fluid in the tissues will be reabsorbed by the lymphatic system and back to your great vessels, particularly, the venous system (SVC & IVC)  The primary function of the lymphatic system is to transport lymph, a fluid containing infection-fighting white blood cells, throughout the body.  Consists of 4 elements: 1) lymph 2) lymphatic vessels 3) lymphatic tissue 4) lymphatic organs  In 1627- Gasparo Aselli ~ "lymphatic system "  Hippocrates reported "white blood" in nodes. III.CONGENITAL MALFORMATIONS  Aristotle described fibers containing colorless fluid observed between blood vessels and nerves. (LYMPH). Lymphangioma  Science of lymphology: early investigations of the anatomy  Benign vascular lesion with fluid filled spaces occuring due and physiology of the lymphatic system, its function, and to abnormal development of lymphatic system. implications related to cancer have propelled technology and  Commonly in neck and axillary region. research to elucidate many of the enigmatic characteristics  50% of lymphangiomas are seen at birth. of the lymphatic system.  90% of lymphangiomas are evident by the age of 2 years. II.DEVELOPMENT Examples:  From this primordial lymphatic system sprout endothelial a. CYSTIC HYGROMA – It is a fluid-filled sac that results from a buds that grow with the venous system to form the peripheral blockage in the lymphatic system. It is most commonly located in the lymphatic plexus. neck or head area. It may be discovered in a fetus during a pregnancy  Lymphangiogenesis, or the formation of primordial ultrasound, or it may be apparent at birth as a soft bulge under the lymphatic system, occurs due to the interaction of certain skin. Page 1 of 13 CMED 1A  (005) LYMPHATIC SYSTEM PART 1 DR. VIVENCIO REFUERZO| 01/25/21 o Also known as Picibanil o Intralesional injection of lyophilized incubation mixture of group A Streptococcus pyogenes of human origin. It induces a local inflammatory reaction with activation of macrophages and production of cytokines (i.e., tumor necrosis factor, TNF), which increase the permeability of endothelial cells and promote lymph excretion. b. LYMPHANGIOMA CIRCUMSCRIPTUM – It is a microcytic lymphatic malformation that appears as a cluster of small firm blisters filler with lymph fluid. It is most commonly found on the neck, IV.OVERVIEW OF THE LYMPHATIC SYSTEM underarm, and tongue. c. CAVERNOUS LYMHANGIOMAS  Failure of one of the initial jugular lymphatic sacs to develop proper connections and drainage with the lymphatic system. Figure 4. Four elements of the lymphatic system  This is a network of tissues, organs, and vessels that help  Result: venous system: focal lymph cysts to maintain the body’s fluid balance and protect it from  Management: pathogens.  Surgical excision  Like the circulatory system, the lymphatic system consists  RT of pumps, which is a series of vessels and a fluid called  Sclerotherapy lymph.  OK-432  Unlike the circulatory system it is a one-way system o Lymph does not circulate around in a loop like blood. o Lymph is collected from the tissues and delivered to blood. V.GENERAL FUNCTIONS 1. Returns fluid from tissue to blood (2-4 liters of interstitial fluid/day). – PREVENTION & RESOLUTION OF EDEMA  ~85% of fluid that leaks out of blood returns to blood via via blood capillaries,  15% returns via lymph capillaries  In 24 hrs lymphatic s return fluids equivalent to entire blood volume  If the lymphatic blood is blocked it leads to EDEMA 2. Returns large molecules to blood. – MAINTENANCE OF INTERSTITIAL FLUID HOMEOSTASIS  25 -50% of blood proteins lead out of capillaries each day, they cannot get back into the capillaries instead the Page 2 of 13 CMED 1A  (005) LYMPHATIC SYSTEM PART 1 DR. VIVENCIO REFUERZO| 01/25/21 lymphatic capillaries pick them up and return them to the  ~1/2 of this comes from the liver and small intestines. blood  If lymphatics are blocked blood proteins decreases leading to fluid imbalance in the body  The general function is for the maintenances of interstitial fluid and homeostasis. 3. ABSORBS AND TRANSPORTS FATS.  Special lymphatic capillaries (lacteals) in villi of small intestines absorbs all lipids and fat-soluble vitamins from digested food bypass  Much of which goes straight to adipose tissue How does a lymph form? (1) The blood plasma passes out of the capillary into the interstitial fluid, while most of the interstitial fluid enters the veins. (2) The excess interstitial fluid containing particulate matter is absorbed by the lymph capillaries. VII.LYMPH MOVEMENT i. Lymph moves into nodes by way of several afferent lymphatic vessels. ii. It then moves through sinus channels lined with phagocytic cells (reticuloendothelial cells/macrophages). iii. It exits via 1-3 efferent lymph vessels – fewer efferent vessels create a bottleneck, which slows down the lymph flow as it is “screened” or filtered before proceeding to the circulatory system. iv. As lymph passes from node to node, the macrophages and 4. HEMOPOIESIS reticular cells in each node remove ~99% of impurities.  Some WBC (lymphocytes, monocytes) are made in lymphatic tissue not bone marrow  Including bodies main supply of lymphocytes VIII.COMPONENTS OF LYMPHATIC SYSTEM 5. BODY DEFENSE AND IMMUNITY  Lymphoid tissue is an important component of the immune 1. Lymphatic capillaries system, it forms a diffused surveillance of the defense  (terminal) 30 – 80 um system in all body tissues and organs  Ubiquitous  Main role of the WBC is for body defense  Absent in CNS, cartilage, bone, spleen, bone marrow,  Lymphatic system screens body fluids and removes alveoli, and respiratory bronchiole. pathogens and damaged cells  Structural features: o High porosity VI.LYMPH o Very small tight junctions between endothelial cells o Anchoring filaments tethering the interstitial matrix to  It is a clear straw-colored fluid plasma with less proteins. interstitial fluid. They attach lymphatic endothelial cells  It has a milky appearance (lipids) after meals. to surrounding tissues.  Lymphocytes: located in the blood stream o Endothelium creates a valve like flap.  Macrophages, hormones, bacteria, cancer, cellular debris, o Lack of basement membrane and smooth muscle viruses cells.  The LS handles 125 ml/hr (2.5 – 2.8 liters a day). o Solely relying on the basic fibers of extracellular matrix of initiation of lymph drainage to reach the precollecting and collecting vessels. Page 3 of 13 CMED 1A  (005) LYMPHATIC SYSTEM PART 1 DR. VIVENCIO REFUERZO| 01/25/21 o Lacteals in the SI are examples of lymphatic capillaries  Swelling of lymph nodes in 2 or more areas of the body is that carry dietary lipids into lymphatic vessels and referred to as generalized lymphadenopathy. It may be ultimately into the blood. caused by viral diseases such as AIDS, mononucleosis, measles, rubella, chickenpox, or mumps. 2. Lymphatic vessels Functions:  Result of the convergence of lymphatic capillaries  Cleanses lymph: removes dead cells and microorganisms. (terminal).  Alert immune system to pathogens.  Also known as collecting vessels  Formation of white blood cells.  They travel alongside veins and arteries, and at irregular intervals empty to lymph nodes..  Lymphatic vessels resemble veins in structure: a. 3 layers – much thinner b. One-way valve – but many more every few mm or so c. Have lymph nodes along its interval or course, for filtration purposes. Figure 6. Anatomy of a lymph node Figure 5. Lymphatic capillaries, located in the spaces between cells, unite to form larger lymphatic vessels. 4. Lymphatic trunks  Result of the convergence of lymphatic vessels/collecting 3. Lymph nodes vessels.  Scattered along the lymphatic vessels are lymph nodes  6 principal lymph trunks: also called lymph glands. 1. Jugular trunks  Encapsulated masses of B cells and T cells. : drain the head and neck  Oval, vary in size like pinhead to lima beans most 2. Subclavian trunks numerous of the lymphatic organs (100’s) : drain the free upper limbs  Clusters of lymph nodes: 3. Bronchomediastinal trunks a) submental & submaxillary : drain the thoracic wall, lung, and heart floor of the mouth – drain nose, lips, and teeth 4. Intercostal trunks b) cervical 5. Intestinal trunk neck – drain the neck and head : drains the stomach, intestines, pancreas, spleen, c) axillary and part of the liver armpit (axilla) and upper chest – drain arm and 6. Lumbar trunks upper thorax, including breasts : drain the free lower limbs, the wall and viscera of d) inguinal the pelvis, the kidneys, the adrenal glands, and groin area – drain legs and genitals the abdominal wall  Swelling of nodes on the neck or behind the ears might be a result of an infection such as a cold, sore throat, or ear infection, or an injury. 5. Lymphatic ducts  Result of the convergence of lymphatic trunks.  Enlarged nodes above clavicles may result from infections  Also called as collecting ducts or tumors in the lungs, breasts, neck, or abdomen.  Swollen lymph on the axilla may be a result of an upper  Lymph passes from lymph trunks to 2 main lymphatic limb infection of metastasis of a tumor of the breasts. ducts, and then drains into venous blood. Page 4 of 13 CMED 1A  (005) LYMPHATIC SYSTEM PART 1 DR. VIVENCIO REFUERZO| 01/25/21  2 major lymphatic ducts: Right lymphatic duct  Thoracic duct (Left lymphatic duct)  Collects lymph from :  Right lymphatic duct - right jugular trunk - right subclavian trunk - right bronchomediastinal trunk  Empties into right subclavian vein  It drains the right of the head and neck, the right upper limb, and the right side of the thorax. Figure 7. Anterior view of lymphatic trunks and ducts. Thoracic duct  Collects lymph from IX. 2 MAJOR LYMPHATIC DUCT  Left bronchomediastinal trunk  Right lymphatic duct :  Left subclavian trunk - Very short  Left jugular trunk - Drains upper right quadrant of the body.  It empties into left subclavian vein - Drains into right subclavian vein.  Drains lymph into venous blood at the junction of the left  Thoracic duct : internal jugular and left subclavian veins. - Much larger and longer drains the rest of the  At the level of T5, the thoracic duct crosses to the left side body. - Drains all the the body below diaphragm and left of the thorax. arm and left side of head, neck and thorax begins  It conveys to the blood all lymph from the lower limbs, just below the diaphragh. pelvic cavity, abdominal cavity, left side of the thorax, and - Anterior to vertebral column lumbar trunks and left side of the head, neck, and left arm intestinal trunks join to form sac-like cysterna chyli o CISTERNA CHYLI drains into left subclavian vein.  Enlarged inferior end of thoracic duct.  Receives lymph from the digestive viscera or. Page 5 of 13 CMED 1A  (005) LYMPHATIC SYSTEM PART 1 DR. VIVENCIO REFUERZO| 01/25/21 X.LYMPHATIC SYSTEM XII.MAJOR ACCESSORY OF LYMPH ORGANS 1. Tonsil 2. Spleen 3. Thymus 4. Lacteal XIII.TONSIL  Masses of lymphoidal tissue embedded in mucous membranes of pharynx  Covered by epithelium with deep pits (crypts)  Crypts often food debris, bacteria, wbc’s, and etc  Several groups of tonsils form a protective ring around the pharynx → Together they form Waldeyer’s ring → Lymphoid tissue → Covered by respiratory epithelium pseudostratified columnar epithelium Three main sets of tonsils (A) Pharyngeal tonsils Found on wall of pharynx (adenoids) behind nasal cavity (nasopharynx-posterior wall) Palatine tonsils -found on post margin of oral cavity XI.LYMPH FLOW -largest and most often Lymph > afferent > lymph node > efferent > lymphatic duct > infected (tonsilitis) circulatory system -Usually infected by Streptococcus and treated  Pressure gradient is above 60mmHg with antibiotic  Passive system ( no pump ) - oral cavity (either side of  One way system to heart posterior end)  Lymph move towards the heart : Lingual tonsils -found on each side of the - Accumulation of proteins in the interstitial fluid. root of the tounge - Milking action of skeletal muscle. (posterior 1/3 of the - Breathing movements. tounge) - Rhythmic contraction of smooth muscle walls in Tubal tonsils -surround the openings of vessel the auditory tubes into the pharynx A. Three main sets of tonsils Page 6 of 13 CMED 1A  (005) LYMPHATIC SYSTEM PART 1 DR. VIVENCIO REFUERZO| 01/25/21 Spleen Functions Defense -helps screen blood and removes pathogens and bacteria Hemopoiesis -origin of monocytes and lymphocytes -Erythropoiesis before birth Erythrocyte and - spleen is “Erythrocyte Platelet destruction graveyard” -Plays an important role in RBC and iron metabolism through macrophage phagocytosis of old and damaged RBC - It recycles iron by sending it to B. Tonsilitis the liver Blood Reservoir -storage of blood (350 ml) XIV.CLINICAL APPLICATION: TONSILITIS -can constrict and pump blood  Infection of the pharyngeal tonsils into circulatory system if  Tonsils are swollen (adenoid – a mass of enlarged lymphatic hemorrhaging tissue between the back of the nose and throat, often hindering -self transfusion (200 ml into speaking and breathing in young children) blood