The document discusses the anatomy and physiology of the lymphatic system. It describes the development of lymphatic vessels and organs like lymph nodes, spleen, thymus, and tonsils during fetal life. It also explains the structure and functions of these organs. The lymphatic system works with the immune system to produce and transport immune cells and lymph throughout the body. It helps maintain fluid balance and transports fat, proteins, and other molecules before returning to the bloodstream.

1. Applied Anatomy
Physiology &
Pathology of
Lymphoreticular
system
Dr. Khaing zay aung
16. 2. 2015

2. The lymphatic system comprises:
 Lymphatic chanals
 Lymphoid organs &
(lymph nodes, Peyer’s patches, spleen, thymus &
tonsils)
 Circulating elements
(lymphocytes and other mononuclear immune cells)

3. Developmental Anatomy
 6 to 7 week of fetal life
 The origin of the lymphatic vessels
is unclear
 May arise from sac like outgrowth
of the endothelium of the veins

4. 6 primary lymph sacs
2 JUGULAR
2 ILIAC
1 RETROPERITONEAL
1 CISTERNA CHILI

5.  These lymph-sacs are developed by the
confluence of numerous venous capillaries
 Which at first lose their connections with
the venous system
 But subsequently, on the formation of the
sacs, regain them

6.  Two main chanals
 The rt and lt thoracic ducts
 They join the jugular sacs with the
cisterna chili
 Drain into the venous system at the
junction of the internal jugular vein
and the subclavian vein
 Numerous anastomoses produce many
variations in the final form of the thoracic
duct.

7. Development of thymus
Develops from the third and
fourth pharyngeal pouches
The stroma arises out of the
endodermal and also
ectodermal in origin

8. 5. Bud of thymus

10. Development of tonsils
 The tonsil buds appear with the formation
of the pharyngeal pouches
 Located in the throat region
 Palatine, lingual and unpaired pharyngeal
tonsils

11. 8.Tonsilar buds

12.  The lymphatic tissues of the intestine,
Payer’s patches, appear later than tonsils.
 The second half of the pregnancy

13. Development of the lymphnodes

14.  The origin of the lymphatic vessels is
unclear
 May arise from sac like outgrowth of
the endothelium of the veins
 The primary lymph nodes develop in
regions that are occupied by lymphatic
sacs.

15. Development of spleen
 From the thickening of the visceral
mesothelium
 Within it there is an accumulation of the
mesenchymal cells
 Along the leftward shift of the stomach, it
resided on the left side of the abdomen
 During the first trimester, macrophages and
precursor cells of erythropoiesis enter into
the spleen
 After 15 wks of gestation, the white pulp and
red pulp appears

16. Development of lymphocytes
 Largest part of the lymphocyte
development occurs in bone marrow,
thymus and the primary lymphatic organs
 Large number of immunocompetent
lymphocytes are produced that colonize
the secondary lymphatic organs,
lymphnodes, tonsils, MALT and spleen
 Distinguish into two types; T & B
lymphocytes

18. Anatomy of lymphatic system
 the lymphatic system parallels the
cardiovascular system
 One way system
 Convey lymph from end organs to the
cardiovascular system

19.  Lymph contains nutrients, oxygen,
hormones, fatty acids, toxins and waste
products.

20. Functions
 Worked together with the immune system
 As immune surveillance that Produce,
maintain, and distribute lymphocyte
 Alternative route of Collection and
transportation of fluid , nutrient ,
proteins and hormones
 Part in maintenance of normal blood
volume
(There is a small net movement of fluid
from the plasma into the interstitial fluid
along every systemic capillary. The total
volume is 3.6 l/day.)

21. Collection of lymph

22. Formation of lymph
 ISF forms at the arterial end of the capillaries
 Most of it returns to its venous ends and venules; the
rest (10—20%) enters the lymph capillaries as lymph.
 As it flows through the lymph nodes, however, it comes
in contact with blood and tends to accumulate more
cells (particularly lymphocytes) and proteins.

23. Lymphatic vessels
 Blind ended tubes
 Endothelial lined (single layer)
 Lymphatic capillaries coalesce to form
larger meshlike network of tubes ka
lymphatic vessels

25. The lymphatic system

26. Lymphatic capillaries
 Absent in bone, bone marrow, teeth,
CNS
 Enter lymphatic collecting vessels
 Lacteals – specialized lymph capillaries
present in intestinal mucosa
 Absorb digested fat and deliver chyle
to the blood

27. Lymphnodes
 Beanshaped structures
 Throughout the lymphatic system
 App: 600 to 700
 Concentrated in the neck, axilla, groin,
mediastinum & mesenteries of the GI
tract.
 Main line of defense by 2 types of cell
lines
 T & B lymphocytes

28.  A lymph node has an outer capsule of
connective tissue from which trabeculae
pass into the deeper tissue.
 Beneath the capsule is a space, the
subcapsular sinus into which the afferent
lymphatics drain after penetrating the
capsule.
 Lymph from the subcapsular sinus passes
via the medullary cords to the hilum of
the lymph node from which the efferent
lymphatics drain.

29.  Both afferent and efferent vessels have
valves which allow only forward flow.
 The node consists of an outer cortex and an
inner medulla and contains lymphatic
sinuses.

30.  Three distinct microanatomical
regions within a lymph node.
Cortex
Paracortex
Medulla

31. 1. Cortex: which contains either primary
or secondary lymphoid follicles;
2. Paracortex: which is the T-cell
dependent region of the lymph node; and
3. Medulla: which contains the medullary
cords and sinuses and also contains
lymphocytes which are much less densely
packed than in the cortex, together with
macrophages, plasma cells and a small
number of granulocytes.

32. Cortex
 consists of primary lymphoid follicles which
are unstimulated follicles, spherical in
shape, containing densely packed
lymphocytes.
 Secondary follicles are present after
lymphocytes have been stimulated
antigenically.

33.  These follicles have an outer ring of small
B lymphocytes surrounding the germinal
centre, which contains largely dividing
lymphoblasts, macrophages and dendritic
cells.

34.  Antigen is trapped upon the surface of the
dendritic cells and presented to ‘virgin’ B
lymphocytes in the presence of T helper
cells.
 These B cells subsequently undergo a series
of morphological and functional changes.
 The function of germinal centre is to
generate immunoglobulin-secreting plasma
cells in response to antigenic challenge.

36. Paracortex
 T-cell-dependent region of the lymph node.
 When a T cell response occurs there is marked
proliferation of cells in this area.
 contains large number of T lymphocytes with
a predominance of helper/inducer cells.
 The cluster of differentiation (CD4) is
expressed by helper/inducer T cells.

37. Medulla
 Lymph enters the marginal sinus of the node and drains
to the hilum through the sinuses which converge into
the medullary region.
 The sinuses are lined by macrophages which
phagocytose foreign or abnormal particles from the
lymph passing through the node, i.e. the filtering
function.

38.  Between the sinuses in the medulla lie
the medullary cords which contain
numerous plasma cells.
 The medullary cords are one of the main
sites of antibody secretion within the
lymph node.

45. Waxing and waning of lymph
nodes
 Enlargement on infections occurs in the
corresponding areas
 Inflammation – swollen glands
 Lymphadenopathy– chronic or excessive
enlargement of lymph nodes
 They received the metastasizing cancer cells
 Spread along the lymphatics
 Nodal status is important

46. Lymphatic vessels
2 main lymphatic ducts
 Right lymphatic duct
drains the upper rt quardrant
 Thoracic duct
drains the remaining tributaries
They have one way valves to prevent any
back flow.

47. Cisterna chyli
 It is a lymphatic sac at the base of the
thoracic duct
 Anterior to the body of L1 or L2
 Formed by the convergence of the lumbar
lymphatic trunks and intestinal lymphatic
trunks

48. Cisterna chyli

49. Thoracic Duct
 Main lymphatic duct of the body
 Originates from the cisterna chili
 Enters into the thorax via the aortic
foramen of the diaphragm
 Situated in the posterior mediastinum
 Receives lymph from the left side of the
head & neck, lt upper limb & lt chest wall
 Empty into the junction of the lt
subclavian vein and internal jugular vein

50. Area of body drained by thoracic duct

51. area of body drained by the right lymphatic duct

52. Thymus
 Bilobed lymphoid organ
 Located in the superior
mediastinum
 maximum absolute size during
puberty between 30 and 40 g
 It regresses after the puberty

53.  Two lobes covered by capsules
 Fibrous septa – divided 2 mm area of lobules
on each lobe
 Each lobule
 dense cortex
 Pale medulla
 Lymphoid stem cells in cortex
 Divided rapidly and daughter T cells become
matured
 Migrated into Medulla -
 T cells sensitive to normal tissue are destroyed

55. Spleen
 Largest lymphoid organ
 75-250 g
 Lies in lt hypochondrium with its long axis
along the 10th rib
 Mainly over the 9th , 10th and 11th ribs
 There is a notch in its inferolateral
surface

56.  Blood supply is from the tortious splenic
artery from the coeliac axis
 Which gives off branches to stomach and
pancreas within the gastrosplenic
ligament
 Divides into superior and inferior
branches

57.  Splenic vein is formed by several
tributaries within the splenic substance
 Joins with the superior mesenteric vein to
form portal vein behind the neck of the
pancreas

58.  Efferent lymphatics in white pulp joins
with the arterioles
 Emerge as nodes at the hilum
 Drains via the retropancreatic nodes to
the coeliac nodes

60. Tonsils
 Aggregates of lymphnodes under the
epithelial lining of the oral and
pharyngeal areas
 Pharyngeal tonsils
 On the roof of the nasopharynx
 Also called the adenoids

61.  Palatine tonsils &
 Lingual tonsils- at the base of posterior
surface of tongue
 These are collectively known as
Waldeyer’s ring

62.  Bld supply is principally from the tonsilar
artery which is the branch of the facial
artery
 Entering at the lower pole of the tonsil
 Also from lingual, ascending palatine and
ascending pharyngeal arteries
 Lymphatic drainage is nodes around the
internal jugular vein to the
jugulodigestric or tonsillar nodes

64. Physiology

65. Functions of LYMPHATIC SYSTEM
 The principal function of the lymphatic
system is the return of protein rich fluid to
the circulation through the lymphatic venous
junctions in the jugular area.

66.  Water
 Electrolytes
 low molecular weight molecules
(polypeptides, cytokines, growth factors)
 Macromolecules - fibrinogen, albumin,
globulins, coagulation and fibrinolytic
factors
 From the interstitial fluid (ISF) return to
the circulation via the lymphatics

67.  Intestinal lymph (chyle) transports
cholesterol, long-chain fatty acids,
triglycerides and the fat-soluble vitamins (A,
D, E and K) directly to the circulation,
bypassing the liver.
 Lymphocytes and other immune cells also
circulate within the lymphatic system.

69. Innate immunity
 Also called natural or native immunity
 Defense mechanisms that are present
before the infection
 First line of defence
 Always ready

70. Innate immunity consists of:
• physical barriers
• secretions with antibacterial activity, including
lactoferrin;
• phagocytic cells: monocytes, macrophages and
neutrophils;
• NK cells (lymphocytes capable of non
MHC restricted killing);

71.  soluble mediators which can enhance the
activity of innate and specific responses:
 C-reactive protein (CRP)
 mannose-binding lectin (MBL)
 cytokines
 soluble enzymatic cascades such as the
complement system

72.  The innate immune system is non-adaptive,
i.e. it cannot adapt its receptors to
recognize an organism which has evolved
and mutated its antigens to evade binding.
 It does not develop memory
 It does not possess antigen specificity
through the specialized and mutable antigen
receptors of immunoglobulins.

73. Adaptive immunity
 Also called acquired or specific immunity
 Mechanisms that are stimulated by
microbes
 Capable of recognizing nonmicrobial
substances called ‘antigens’.

74.  These are more effective than innate
ones
 Mediated by lymphocytes and antibodies
which amplify and focus non-specific
responses and provide additional effector
functions
 These cells are organised into lymphoid
tissues
 Cellular (cell mediated) immunity refers
to lymphocyte-mediated effector
responses (T helper (Th) and cytotoxic
cells) of the specific immune response

75.  Cellular immunity refers to lymphocyte-
mediated effector responses (T helper
and cytotoxic T cells) of the specific
immune response
 Humoral immunity often refers to the
antibody arm of the specific immune
response.

76.  Antibodies are usually not produced without
some cell-mediated response to the same
antigen
 T and B lymphocytes possess infinitely
variable antigen receptors which can
clonally expand.
 Antigen receptors which can be secreted
into interstitial fluid and onto mucosal
surfaces are called antibodies.
 Antibodies can activate complement and
also enhance opsonization of antigen to
facilitate phagocytosis.

77.  Both innate and adaptive mechanisms
exponentially amplify the immune response
 since clonal expansion of lymphocytes
increases the number of cells reactive with
an antigen.
 Cytokines and complement components
recruit other immune effector mechanisms
and antibodies activate complement and
phagocytes.
 The specific adaptive immune response is thus
flexible and adaptable.

78.  Capable of responding to antigens which
have not been previously encountered
 Including those generated in organisms by
the selecting pressures of an effective
adaptive immune response.
 Many pathogens have specific
adaptations/mutations to evade previous
immunological memory responses (e.g.
influenza antigen variability) or to suppress
the normal mechanisms of immune
destruction.

79. ANTIGENS
 An antigen is any substance which can
elicit a specific immune response.
 Consists of many epitopes.
 An epitope is a specific sequence of a
protein or carbohydrate recognized by the
receptor molecules of the immune system
(antibody or T cell receptor)

80.  Antigens can be divided into
foreign - non-self, allogeneic,
xenogeneic, etc.
Autoantigens – self antigens

81. ANTIBODIES
 An antibody is a soluble protein immune
receptor produced by B lymphocytes,
consisting of two identical antigen-
binding sites .
 The antigen specificity of the antibody
resides in the antigen-binding variable
regions (the fragment antigen-binding,
Fab, portion).

82.  Antibodies are divided into different
isotypes (classes) which have different
functional attributes according to Fc
fragments
 Antibodies which bind to antigen or cells
and activate complement via the Fc region
thus recruit, activate, amplify and target
non-specific defense mechanisms.

84. Functions of the spleen
1. Haematological function
2. Immunological function

85. Haematological functions
 Site of quality control of erythrocyte
population
 Removes fragmented or damaged red
cells from circulation k/a culling
 Remodeling of surface of maturing
erythroctytes where by maintaining the
membrane surface area and volume ratio

86.  Removal of intraerythrocyte inclusions s/a
Heinz’s bodies, Howel-Jolly bodies k/a
pitting
 Clearance of particulate matter from the
circulation – imp function for the timely
immune response to blood borne antigens
 Sequestration of plalets

87.  Haemopoiesis
 Only in fetal life
 No bld formation in the after birth
 Revision of fetal pattern of haemopoiesis
in certain diseases

88. Immunological function
 Each population of lymphocyte is a
constant flux
 ¼ of body’s population of T lymphocytes
is in the spleen at a point time
 Humoral response following antigenic
stimulation involves co-operation
between T & B lymphocytes on the
surface of large dentritic cells

89.  Germinal centres ( secondary follicles)
later appear within the primary follicle
 Reach their maximum development in
about 8 wks following antigenic
stimulation
 Antibody response is relatively decreased
after splenectomy

90.  Also influence the opsonization of
pneumococci in non immune individuals
 Susceptible to them after splenectomy

92. Pathology
 Reactive lymphadenitis
 Tuberculous lymphadenitis
 Lymphoedema
 Lymphomas

93. Reactive Lymphadenitis
 Infections and nonmicrobial inflammatory
stimuli not only cause leukocytosis but
also involve the lymph nodes
 often associated with lymph node
enlargement (lymphadenopathy)
 may be acute or chronic
 histologic appearance of the nodes is
entirely nonspecific

94. Tuberculous lymphadenitis
 Especially neck glands
 Present as cervical lymphadenopathy
 Cold abscess
 Lymphnodes are rubbery and matted
together
 Eventually it can progress to collar stud
abscess formation & sinus

95.  Tissue diagnosis by excisional biopsy
 Granuloma formation with grossly
caseation necrosis
 Definitive Rx is antituberculous
chemotherapy

96. Lymphoedema
 Abnormal lymph swelling
 Caused by accumulation of increased
amount of high protein ISF
 Secondary to defective lymphatic
drainage in the presence of near normal
net capillary function

97. Pathophysiology
 Normal capillary function
 Oedema fluid is high protein content
 Results from
 Lymphatic aplasia
 Hypoplasia
 Dysmotility
 Obliteration by inflammation
 Infective or neoplastic process
 Surgical extirpation

98. Two main types
 Primary
 Unknown cause
 Thought to be congenital lymphatic
dysplasia
 Secondary
 Clear underlying cause

99. Aetiological classification of
lymphoedema
Primary
 Congenital (onset <2 years old):
 sporadic
 familial (Nonne–Milroy’s disease)
 Praecox (onset 2–35 years old):
 sporadic
 familial (Letessier–Meige’s disease)
 Tarda (onset after 35 years old)

100. Secondary
 lymphoedema
 Parasitic infection (filariasis)
 Fungal infection (tinea pedis)
 Exposure to foreign body material (silica
 particles)
 Primary lymphatic malignancy
 Metastatic spread to lymph nodes
 Radiotherapy to lymph nodes
 Surgical excision of lymph nodes
 Trauma (particularly degloving injuries)
 Superficial thrombophlebitis
 Deep venous thrombosis

101. Grading of lymphoedema
(Brunner)
 Subclinical
 excess interstitial fluid and histological
abnormalities in lymphatics and lymph nodes
but no clinically apparent lymphoedema
 Grade I
 Oedema pits on pressure and swelling largely
or completely disappears on elevation and bed
rest

102.  Grade II
 Oedema doesn’t pit and doesn’t reduce
upon elevation
 Grade III
 Oedema is associated with irreversible skin
changes e.g; fibrosis or papillae

103. Clinical features
 Characteristically involves foots
 Contour of ankle is lost
 Toes appears square
 Skin on the dorsum of the toes cannot be
pinched “Stemmer’s Sigh”
 Ulceration is unusual
 Ulceration and non healing bruises should
raise the suspicion of malignancy

105.  Lymphangiosarcoma was originally
described in post mastectomy oedema
 “Stewart-Treves” syndrome
 0.5% of patients
 Mean onset is 10 yrs
 Can develop in longstanding lymphedema
“20 yrs”

106. Malignancies associated with
lymphoedema
 Lymphangiosarcoma
 Kaposi’s sarcoma
 SCC
 Liposarcoma
 Malignant melanoma
 Malignant fibrous histocytoma
 BCC
 lymphoma

107. Filariasis
 Common cause of lymphedema worldwide
 Infectious disease caused by viviparous
nematodes “Wucheria bancrofti”
 Vector “mosquitos”
 Parasites enters the lymphatics via blood
 Lodges in lymphnodes
 Causing fibrosis and obstruction

108.  Either by direct damage or by immune
response of host
 Degree of lymphedema is often massive
referring to as elephantiasis
 Diethylcarbamazine destroys the
parasites but unable to reverse the
lymphedema

110. Investigations
 Routine tests
 CP, U&E, creatinine, LFT, T & DP, albumin, CRP
 Lymphangiography
 Lymphoscintigraphy
 CT
 MRI
 USG
 Limb volume measurement

111. Management
 Relief of pain
 Control of swelling
 Skin care
 Manual lymphatic drainage
 Multilayer lymphedema bandaging and
compression garments
 Exercise
 Drugs

112.  Surgery
 Bypass procedures
 Liposuction
 Limb reduction procedures

116. lymphomas
Hodgkin’s
lyphomas
Non Hodgkin’s
lymphomas

117. Hodgkin’s lymphomas
 Reed Stemberg giant cell
 Mainly arise from B lymphocytes
 Lymph node enlargement is often cervical
 Rubbery consistency
 Hepatosplenomegaly
 General symptoms of malignancies
 Diagnosed by lymph node histology and
bonemarrow aspirate and trephine biopsy

118. 12 yrs old boy

119. Non Hodgkin’s lymphomas
 70% are B cell origin
 May present without typical lymphnode
enlargement
 Hepatosplenomegaly and other features
of malignancy
 Invx as in HL
 Treatment is mainly by chemotherapy
regimens

120. Thymic tumours
 May arise from either epithelium or
lymphoid tissue or both
 May present as
 Mediastinum mass
 Associated myasthenia gravis
 Associated immune deficiency states
 Treatment is by thymectomy

121. Gastric lymphoma
 Primary gastric lymphoma ~ 5% of all
gastric neoplasms
 most prevalent in the sixth decade of
life.
 most commonly occur in the gastric
antrum
 Primary gastric lymphomas are B cell-
derived
 arising from the mucosa-associated
lymphoid tissue (MALT)

122.  At an early stage, the disease takes the
form of a diffuse mucosal thickening,
which may ulcerate
 Presented as – pain, weight loss , bleeding
as s/s of Ca stomach

123.  Diffuse large B-cell lymphoma (55%)
 Associated with immunodeficiencies and H. pylori
infection
 Extranodal marginal cell lymphoma (MALT) (40%)
 Burkitt’s lymphoma (3%)
 associated with Epstein-Barr virus infections, highly
aggressive , younger age,
 Site – cardia or body of stomach
 Mantle cell and follicular lymphomas (each < 1%).

124. Management
 OGDS
 endoscopic biopsy ,not specify with endoscopic features
 Type of lymphoma
 Imaging
 EUS
 CT chest and abdomen
 H. pylori testing
 by histology and, if negative, confirmed by serology

125. Treatment
 multimodality treatment program
 Resection - controversial
 Chemotherapy plus radiation therapy: CHOP
(cyclophosphamide, hydroxy-daunomycin, Oncovin,
prednisolone)

126.  Early-stage MALT lymphomas
 Diffuse large B-cell lymphoma
 H. pylori eradication alone – Successful
eradication resulted in remission in more
than 75% of cases
 Follow up
 repeat endoscopy in 2 months to
document clearance of the infection as
well as biannual endoscopy for 3 years to
document regression