Assignment on Anatomy & physiology of lymphatic system.

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.
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 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
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Lymphatic system Function:

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.
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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
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Lymph Nodes:

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:
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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

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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
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Immunity:

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
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Systemic symptoms: Fever, Night sweats ,Weight loss
If marrow infiltrated, can have leukemic component

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
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Classification of indolent lymphomas- later

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:
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Pathology
 Benign equivalent is replicating small noncleaved cell of
germinal center:
 Diffuse infiltration of lymph node
 Very high mitotic rate, lot of ineffective proliferation;
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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.  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
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Anaplastic large cell lymphoma, T/null-cell
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

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
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CMS: 3855
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By: Tahir Ramzan