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Anatomy & physiology of lymphatic system


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Assignment on Anatomy & physiology of lymphatic system.

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Anatomy & physiology of lymphatic system

  1. 1. Assignment No 1 pathology II 16-09-13 “Enumerate the Anatomy and Physiology of Lymphatic system. Discuss the pathological features with reference to the Inflammation and Infection in the Lymphatic System” “Anatomy & Physiology of Lymphatic System”  Consists of lymph, lymph vessels, lymph nodes, lymphatic tissue, and 4 organs  Tonsils  Spleen  Thymus Gland  Peyer’s Patches Works in conjunction with the circulatory system to remove wastes and excess fluids from the tissues. Page  Drain protein-containing fluid from tissue spaces (primary function). o Interstitial fluid can cause edema  Transport fats from the digestive system o Via lacteals in the villi of the small intestine  Produce lymphocytes o A type of leukocyte 1 Lymphatic system Function:
  2. 2.  Develop immunities o Antibodies What is Lymph? A thin, watery fluid composed of intercellular or interstitial fluid, which 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 this fluid enters the lymphatic system, it is known as lymph. Lymphatic Vessels: Located throughout body in almost all of the tissues that have blood vessels Small, open-ended lymph vessels act like drainpipes and are called lymphatic capillaries Lymphatic capillaries pick up lymph at tissues throughout body Capillaries then join together to form larger lymphatic vessels, which pass through lymph nodes. Contractions of skeletal muscles against lymph vessels cause the lymph to flow through the vessels. Lymphatic vessels also have valves that keep lymph flowing one-way Drains lymph into blood via thoracic duct (main) or right lymphatic duct. Page Popularly called “ glands”. Located all over body, usually in groups or clusters; Small, round or oval masses ranging in size from that of a pinhead to an almond. Filter lymph and remove impurities such as carbon, cancer cells, pathogens, and dead blood cells, Produce lymphocytes and antibodies 2 Lymph Nodes:
  3. 3. Lymphatic Tissues: Tonsils – masses of lymphatic tissue that filter interstitial fluid; there are 3 pairs Palatine tonsils: located on each side of the soft palate Pharyngeal tonsils: (also called adenoids) located in the nasopharynx Lingual tonsils: located on the back of the tongue T&A not performed as often due to better understanding of importance of these tissues. Spleen An organ located beneath the left side of the diaphragm and in back of the upper part of the stomach Produces leukocytes and antibodies Destroys old erythrocytes Stores erythrocytes to release into bloodstream if excessive bleeding occurs Releases hemoglobin to be recycled Filters metabolites and wastes from body tissues Thymus: Page 3 A mass of lymph tissue located in center of upper chest Atrophies after puberty and is replaced by fat and connective tissue During early life, it produces antibodies and manufactures lymphocytes to fight infection Its function is taken over by the lymph nodes
  4. 4. Page Ability of body to resist infection from pathogens o Active – response from antigen or vaccination o Passive – via placenta, breast milk, or antivenom Antigens o Foreign proteins that gain access to our bodies via circulatory, digestive, respiratory, urinary and reproductive systems o Cause immune system to produce high molecular weight proteins called antibodies 4 Immunity:
  5. 5. Antibodies or Immunoglobulins o Bind with specific antigens o Binding causes agglutination o Leukocytes eat agglutinate by phagocytosis ___“Pathological Features”___ Hodgkin lymphoma: Hodgkin lymphoma is a less common nodal disease whose diagnosis is based on the detection of a characteristic cell, the Reed Sternberg cell, in the appropriate histologic setting There are several (five) histologic subtypes, but prognosis is based primarily on extent of disease.Hodgkin lymphoma is a more curable disease than non-Hodgkin lymphomas Now watch me confuse this relatively straightforward information with the details. Clinical Features: Enlarging mass(es), typically painless, at sites of nodal tissue Compression, infiltration of hollow organs Pain, obstruction, perforation Interference with normal organ functionSolid organ infiltration- kidneys, liver, bone marrow Page 5 Systemic symptoms: Fever, Night sweats ,Weight loss If marrow infiltrated, can have leukemic component
  6. 6. NHL 2: Recapitulate the biology and immunophenotype of normal cell counterpart Several cytologically and immunologically recognizable stages of normal lymphoid maturation --> several subtypes of lymphoma Clonal malignancies, derived from a single cell that has undergone a malignant transformation, mutation Best initially conceptualized as two major clinical types o Indolent lymphomas o Aggressive lymphomas Indolent Lymphomas: Lymphomas frozen at stages not normally replicating, but may be circulating Diseases of slow accumulation, due to defective apoptosis Often widespread at diagnosis Prolonged natural history, median survivals >5 years Will usually respond to chemo- or radiation therapy Will usually relapse, but respond to same or alternative tx Currently incurable unless o Localized disease or o Marrow ablation with some type of stem cell transplant Page 6 Classification of indolent lymphomas- later
  7. 7. Aggressive lymphomas: Lymphomas frozen at stages characterized by replication and accelerated growth Diseases of defective cell cycle control More often localized at presentation than indolent lymphomas More often extranodal Despite short natural history, curable disease in some with aggressive therapy o Approximately 30-40% of adults o 50-80% children All childhood lymphomas of this type Brukkit’s Lymphoma: Page Pathology  Benign equivalent is replicating small noncleaved cell of germinal center:  Diffuse infiltration of lymph node  Very high mitotic rate, lot of ineffective proliferation; 7 Clinical  3% lymphomas  Disease of adults and children- median age 31  Initially recognized in Africa by Thomas Burkitt  Association with Epstein Barr virus infection  Localization in jaw  In US, usually presents in ileocecal region of children  1/3 of all childhood lymphomas  Earlier eras, very aggressive and rapidly fatal  Now, ~70-80% children curable  40% of adults
  8. 8.  Attracts macrophages to phagocytize> starry sky pattern at low power  Cytology: round nucleus, smaller than that of reactive macrophage  Vesicular chromatin and 2-5 nucleoli  Immunophenotype: o Positive: Monoclonal light chain, CD19, CD10 o Negative: CD5 T cell lymphomas – Precursor T: Pathology   Benign equivalent immature T cells of thymus  Cytology: “Blast cells” of intermediate size with oval to “convoluted” nuclear profiles, fine chromatin and 0-1 nucleolus  Again need immunology to distinguish from pre-B Histology: Diffuse infiltration of thymus/adjacent lymph nodes Predominantly leukemic/disseminated  T-cell prolymphocytic leukemia    T-cell large granular lymphocytic (LGL) leukemia NK cell leukemia Adult T-cell leukemia/lymphoma Predominantly nodal  Angioimmunoblastic T-cell lymphoma Peripheral T-cell lymphoma unspecified 8 Anaplastic large cell lymphoma, T/null-cell Page  
  9. 9. Predominantly extranodal  Mycosis fungoides   Sezary syndrome     Subcutaneous panniculitis-like T-cell lymphoma Primary cutaneous CD30+ T-cell lymphoproliferative disorders NK/T cell lymphoma, nasal and nasal-type Enteropathy-type intestinal T-cell lymphoma Hepatosplenic T-cell lymphoma Hodgkin’s Lymphoma: Less common than NHL; ~ 10,000 cases per year Age incidence bimodal, with one peak in late adolescence, young adulthood, second peak beginning in sixth decade Bimodal curve shifts to younger ages in poorer countries Unlike NHL, HL diagnosed by the presence of a minor cellular component, the Reed-Sternberg cell, found in the appropriate microscopic cellular background ____________ END ____________ To: Sir Mubben Page CMS: 3855 9 By: Tahir Ramzan