Notes on lymphatic system

1. LYMPHATIC SYSTEM DR
SUMANGALA
DANIEL

2. CONTENTS
1. FORMATION AND COMPOSITION OF LYMPH
2. LYMPH VESSELS
3. LYMPH FLOW- FACTORS AFFECTING LYMPH
FLOW
4. LYMPHATIC ORGANS
5. LYMPH NODES
6. LYMPHATIC DRAINAGE
7. SPLEEN
8. THYMUS GLAND
9. DISEASES OF LYMPHATIC SYSTEM
10. DISEASES OF LYMPH NODES
11. MALIGNANT TUMOURS OF LYMPHOID TISSUE

3. FORMATION AND COMPOSITION OF LYMPH
 LYMPHATIC SYSTEM IS AN ACCESSORY
COMPONENT OF THE CIRCULATORY SYSTEM.
 THE FLUID FLOWING THROUGH THIS SYSTEM
IS TERMED – LYMPH
 LYMPH IS – A CLEAR, WATERY FLUID (except
LYMPH FROM THE LACTEALS OF INTESTINAL
VILLI – IS MILKY- CALLED CHYLE)
 LMYPH- IS A TISSUE FLUID- THAT DRAINS INTO
THE BLOOD VIA THORACIC DUCT AND RIGHT
LYMPHATIC DUCT
 LYMPH- CONTAINS -- LYMPHOCYTES
 LYMPH IS LIKE PLASMA- BUT HAS LESS
PROTEIN

4. COMPONENTS OF LYMPHATIC SYSTEM
 LYMPH VESSELS
 LYMPH ORGANS-
 LYMPHATIC SYSTEM IS
PRESENT IN ALL ORGANS-
EXCEPT CENTRAL NERVOUS
SYSTEM AND CORNEA OF THE
EYE

5. LYMPHATIC CAPILLARIES
Commence as blind
sacs in tissue spaces-
they are larger in size
than blood capillaries,
more irregular and
endothelium is more
permeable. LYMPH
from lymph capillaries
enters- LARGE
LYMPHATIC
VESSELS

6. LYMPH CAPILLARIES
Lymphatic capillaries are formed
by a one cell-thick layer of
endothelial cells , allowing
interstitial fluid from outside to
flow into them via overlapping
cells.
When interstitial pressure is low,
the endothelial flaps close to
prevent “backflow “ or leaking out
of lymph the lymph capillaries
As interstitial pressure outside
increases, the spaces between
the cells open up, allowing the
fluid to enter in.

8. COMPOSITION OF LYMPH
 LYMPH- CONTAINS – LYMPHOCYTES
 ALL OTHER SUBSTANCES PRESENT IN PLASMA ARE
PRESENT IN LYMPH-

9. LYMPH VESSELS
 CENTRAL :
 PERIPHERAL :
 LYMPHATIC CAPILLARIES
 Commence as blind sacs in tissue spaces- they are
larger in size than blood capillaries, more irregular and
endothelium is more permeable. LYMPH from lymph
capillaries enters- LARGE LYMPHATIC VESSELS
 LARGE LYMPHATIC VESSELS – are like veins but have
many valves – they pour lymph into regional lymph
nodes- that drain a particular area-
 LYMPH NODES- filter the Lymph and propel it forward
through larger lymphatic vessels to the main lymphatic
trunk
( THORACIC DUCT AND LYMPHATIC DUCT )

10. LYMPHATIC VESSELS
 THORACIC DUCT
 The thoracic duct is the largest lymphatic vessel in
the human body. Around 75% of the lymph from the
entire body
 EXCEPT- (the right upper limb, right breast, right
lung and right side of the head and neck,)
 ORIGIN : starts at upper end of a lymphatic sac-
CISTERNA CHYLI- at L1 vertebrae- it receives right
and left lumbar trunks and intestinal trunks
 COURSE – enters thorax through diaphragm – it
ascends up behind arch of aorta- above clavicle and
opens at junction of left subclavian and internal
jugular veins

11. Rate of lymph flow
 120ml/hour
 2- 3 litres of lymph is drained into blood everyday
 Factors- affecting lymph flow
 Greater interstitial fluid pressure
 Lymphatic pump- stretching of smooth muscles
when lymph accumulates
 External compression- muscles, movemnet
 Increased permeability- more toxins, less oxygen,
increase in temperature

12. Blood
capillaries
Lymph
capillaries
Lymp
h
vesse
ls
Lymp
h
nodes
Lymph
vessels and
ducts and
ducts
JUNCTION OF INTERNAL
JUGULR AND SUBCLAVIAN
VEIN

14. LYMPHATIC ORGANS
 THE LYMPHATIC ORGANS ARE A PART OF
MONONULCEAR PHAGOCYTES SYSTEM –
PREVIOUSLY CALLED AS
RETICULOENDOTHELIAL SYSTEM
 THEY CONTAIN AGGREGATES OF
 LYMPHOCYTES,
 MACROPHAGES
 AND PLASMA CELLS.

16. BONE MARROW
 IT IS a gelatinous tissue that fills the medullary cavity of
the long bones- and spaces between traberculae – there
are 2 types of bone marrow
 RED – also called myeloid tissue
 YELLOW – fatty tissue
 Red bonemarrow, gets it red colour from the
haemoglobin in red blood cells. It is present throughout
the skeleton at foetal life and birth but is gradually
replaced by yellow bone marrow. In adult life red bone
marrow remains only in vertebrae ,ribs, sternum,
clavicle,scapula,hip bones and upper end of humerus
and femur. Red bone marrow contains blood forming
HAEMATOPOIETIC- STEM CELLS – that produce
RBC,WBC,PLATELETS.
 YELLOW BONE MARROW – contains MESENCHYMAL
STEM cells – that produce- FAT CARTILAGE AND
BONE.

17. LYMPH NODES
 SMALL OVAL BODIES- situated along the course of
lymph vessels – they form groups or chains in close
association with blood vessels .
 MICROSCOPIC STRUCTURE
 CAPSULE- Surrounds the node and divides it-
 CORTEX- PERIPHERAL PART - which contains
lymphocytes and forms lymphatic follicles – the
follicles develop central germinal center- which
produce B lymphocytes in response to antigen
 MEDULLA –inner part –has lymphocytes (B and T)
macrophages and plasma cells.

18. FUNCTION OF THE LYMPH NODE
 FILTER THE LYMPH- SEPARATE particles like
carbon, caner cells, worn out cells
 PHAGOCYTOSIS- of the particles
 TRAP AND PRESENT – antigen to lymphocytes for
interaction
 PRODUCE- LYMPHOCYTES at germinal centre
 IMMUNITY –
 CELLULAR- T LYMPHOCYTES
 HUMORAL –B LYMPHOCYTES

19. Lymphocytes-

21. REGIONAL NODES
 SUPERFICIAL NODES – CAN
BE PALPATED when enlarged –
as they are present in superficial
fascia along the veins
 DEEP NODES – arranged along
deeper vessels- may be difficult to
palpate

22. Lymph node- local police station

23. MACROPHAGE
B-
LYMPHOCYTES
T –
LYMPHOCYTE
S

25. LYMPHATIC
DRAINAGE OF HEAD
AND NECK
 SUPERFICIAL
LYMPH NODES of
the head and neck
drain into the DEEP
CERVICAL NODES-
that lie along carotid
sheath. The deep
cervical nodes drain
deeper parts- larynx,
pharynx and thyroid
gland and form
JUGULAR
LYMPHATIC
TRUNKS.
 Left jugular trunk
join THORACIC
DUCT
 Right jugular trunk
joins RIGHT
LYMPHATIC DUCT

26. LYMPHATIC DRAINAGE OF
UPPER LIMB
AXILLARY LYPMH NODES –
drain upper limb and the
breasts
 SUPERFICIAL-
 SUPRATROCHLE
AR AND
INFRACLAVICUL
AR DRAIN INTO
AXILLARY
NODES
 DEEP- AXILLARY
LYPMH NODES –
drain upper limb
and the breasts (
anterior nodes,
lateral,posterior,
central and apical)
join to form
SUBCLAVIAN
TRUNK-

27. LYMPHATIC DRAINAGE OF LOWER
LIMB
INGUINAL LYPMH NODES –
 SUPERFICIAL INGUINAL-
 which has an upper group-
above inguinal ligament
(drains gluteal area, anterior
abdominal wall below
umbulicus)
 Lower group- arranged
along saphenous vein-
drains- lower limb
 DEEP- INGUINAL NODES –
lie medial to femoral vein
receive from superficial
inguinal nodes- and deeper
tissues of lower limb and
glans penis/clitoris.
 POPLITEAL – drain lateral part
of foot and knee joint and send
efferents to deep inguinal nodes

28. RIGHT SIDE- SCALP,FACE NECK LEFT SIDE- SCALP, FACE
NECK
DEEP CERVICAL. L. NODE
DEEP CERVICAL L. NODE
LEFT JUGULAR TRUNK
RIGHT- JUGULAR TRUNK
LEFT UPPER LIMB
AXILLARY LYMPH
NODE
RIGHT UPPER LIMB
AXILLARY LYMPH
NODE
SUB CLAVIAN
TRUNK
SUBCLAVIAN
TRUNK
RIGHT- POPLITEAL
NODES
LEFT
POPLITEAL
NODES
INGUINAL
NODES
ILIAC NODES
PARA-AORTIC
NODES
PARA-AORTIC
NODES
ILIAC NODES
RIGHT- LUMBAR
TRUNK
LEFT – LUMBAR
TRUNK
INGUINAL
NODES
PRE-AORTIC
NODES
INTESTINAL
TRUNK
CISTERNA
CHYLI
BRONCHOMEDIASTINAL
TRUNK
BRONCHOMEDIASTINAL
TRUNK
MEDIASTINALNODES MEDIASTINALNODES
V V
RIGHT
LYMPHATI
C DUCT
THORACIC
DUCT

29. LYMPHATIC
DRAINAGE OF PELVIS
 EXTERNAL ILIAC
NODES –receive lymph
from deep inguinal
nodes
 INTERNAL ILIAC
NODES – drain pelvic
viscera and gluteal
region
 SACRAL NODES –
drain prostrate, seminal
vesicle, rectum, cervix
and drain into internal
iliac nodes

 COMMON ILIAC
NODES – receive
efferents from external
and internal iliac nodes
and send their efferents
to
 PARA- AORTIC NODES

30. LYMPHATIC DRAINAGE OF ABDOMEN
 PREAORTIC NODES – lie IN FRONT OF AORTA
 drain GI tract, liver, gall bladder, spleen, pancreas - their
efferents form INTESTINAL TRUNKSwhich join the cisterna
chyli . -COELIAC, SUPERIOR MESENTERIC, INFERIOR MESENTERIC
NODES
 PARA-AORTIC NODES – lie on the side of the aorta
 They drain the kidneys, gonads, ureters, suprarenals, posterior
abdominal wall –Drain pelvic viscera- as they are receiving
lymph from common iliac nodes -The efferents of para aortic
nodes form
 right and left LUMBAR TRUNKS
 which join CISTERNA CHYLI

33. LYMPHATIC DRAINAGE OF CHEST
 CHEST
 The superficial lymphatic vessels converge in the
subcutaneous space and take lymph back to
the AXILLARY LYMPH NODES
 The deep lymphatic system, on the other hand, drain to
the intercostal nodes, as well as to
the parasternal and diaphragmatic nodes.

34. LYMPHATIC DRAINAGE OF
THORAX
(P.A.I.D - MED)
 WALL OF THORAX DRAIN INTO (
P.A.I.D)
 P-PARASTERNAL NODES-
ALONG INTERNAL THORACIC
VESSEL
 A-AXILLARY NODES- IN AXILLA
 I-INTERCOSTAL – ON
POSTERIOR END OF
INTERCOSTAL SPACES
 D-DIAPHRAGMATIC NODES-
ON UPPER SURFACE OF
DIAPHRAGM
 THE THORACIC VISCERA DRAIN
INTO ( MED)
 the MEDIASTINAL nodes which
drain trachea, bronchi, heart .
 Their efferents form
BRONCHOMEDIASTINAL
TRUNKS ON EACH SIDE- which
opens at the jucntion of internal
jugular and subclavian vein of it’s
own side.
BRONCHO
MEDIASTINAL

39. SPLEEN
 LOCATION – LEFT
HYPOCHONDRIAC
 SPLEEN HAS –
 2 BORDERS – superior and
inferior
 2 POLES – posterior and
anterior
 2 SURFACES –
diaphragmatic surface-
separating it from left lung
 Visceral surface – related to
stomach, left colic flexure,
left kidney
 BLOOD SUPPLY- SPLENIC
ARTERY – AND DRAINED
BY SPLENIC VEIN WHICH
JOINS SUPERIOR
MESENTERIC VEIN TO
FORM PORTAL VEIN .

40. FUNCTIONS OF SPLEEN
 PHAGOCYTOSIS – old abnormal cells are destroyed by
spleen and breakdown products like bilirubin and iron
pass to liver through the splenic or portal vein
 STORAGE OF BLOOD – about 350 ml of blood is
present in the spleen - on sympathetic stimulation ,
blood from spleen rapidly enters circulation to increase
blood volume – is conditions such as bleeding
(haemorrhage)
 IMMUNE RESPONSES – spleen has T and B
lymphocytes that are activated in the presence of
antigen. Therefore some infections can cause
spleenomegaly (enlargement of spleen)
 ERYTHROPOIESIS –site of red blood cell formation in
foetus.
 the spleen is constantly filtering the BLOOD in order to
detect the presence of microorganisms

41. White pulp is the main lymphoid
tissue of the spleen. It is the
accumulation of lymphocytes
around an arterial vessel..it is the
first to react if microbes reach the
spleen through the bloodstream.
.Red pulp consists of splenic
venous sinuses and cords (of
Billroth), linings of splenic
macrophages around the
sinuses..

42. DISEASES OF THE SPLEEN
 SPLENOMEGALY- SPLEEN IS
ENLARGED
 INFECTIOUS DISEASES- MALARIA, TYHPOID
 CIRCULATORY DISORDERS –RT SIDED HEART
FAILURE
 BLOOD DISEASES – ABNORMAL RBC- MICROCYTIC
ANAEMIA ,HAEMOLYTIC ANAEMIA
 ANAEMIA –OCCURS DUE TO PREMATURE DESTRUCTION
OF RBS, PHAGOCYTOSIS OF WBC AND PLATELETS BY SPLEEN
 CANCER OF THE SPLEEN

43. THYMUS GLAND
 Thymus is a central organ of Lymphatic system
 Location- superior mediastinum
 Relations-
 Anteriorly- sternum
 Posteriorly – arch of aorta
 Laterally- lungs

44. THYMUS GLAND
 The thymus gland is a
pink, lobulated
lymphoid organ,
located in the thoracic
cavity and neck. In the
adolescent, it is
involved the
development of
the immune system.
After puberty, it
decreases in size and
is slowly replaced by
fat.
 The gland is mainly
located within the
thoracic superior
mediastinum,
 posterior to the
manubrium of the
sternum

45. STRUCTURE AND
FUNCTIONS- OF
THYMUS  2 LOBES
 EACH LOBES HAS
A FIBROUS
CAPSULE
 OUTER CORTEX
which is packed with
LYMPHOCYTES
 INNER MEDULLA
which has less cells
and degenerated
epithelial cells
arranged in a
lamellae- called
HASSALL corpuscle

46. FUNCTIONS OF
THYMUS
 PRODUCTION OF MATURE LYMPHOCYTES
 LYMPHOCYTES originate from pluripotent stem cell
of bone marrow. Those that enter THYMUS develop
into acitvated T lymphocytes. These leave the thymus
and enter blood. The thymus thus
produces mature T
LYMPHOCYTES that can react with
specific foreign antigen.
 PRODUCTION OF THYMOSIN – hormone secreted
by thymus gland .

47. In the THYMUS –CELLS MATURE AND
DIFFERENTIATE
B- LYMPHOCYTES
T- LYMPHOCYTES

48. MUCOSA ASSOCIATED
LYMPHOD TISSUE-MALT-
(to remember- P.O.T.A.TO
)
 P- PEYER’S PATCHES IN
ILEUM AND LYMPHATIC
FOLLICLES
 O- LYMPHATICS IN
OESOPHAGUS
 T- LYMPHAIC TISSUE IN
TRACHEA, BRONCHI, LUNGS
 A- APPENDIX- HAS
LYMPHATIC TISSUE (called as
abdominal tonsil)
 TO- TONSILS – PALATINE,
LINGUAL,TUBAL,
PHARYNGEAL
 MALT –provides- first
line of defense
 FOLLICLES- proved local
defense
 Act as RESERVOIRS of
lymphocytes

49. DISEASES OF LYMPH VESSELS
 Because lymph in constantly circulating in the lymph
vessels, it can spread a disease ,infections and
cancer (malignant disease )
 Spread of infectious disease – lymph vessels
carry infected material from infected site. Usually at
local site – tissue macrophages act as first line of
defense- additionaly other cells like neutrophils and
monocytes also try to phagocytose the
microorganism and prevent spread- it this is not
effective, then the germs enters the lymph vessels
and is carried to lymph nodes. Here the lymph nodes
try to stop the spread but if that fails, the infection
enters the blood stream .

50. DISEASES OF LYMPH VESSELS
 SPREAD OF MALIGNANT TUMOUR- THE wall ofthe lymph vessel is eroded by
cancer cells (malignant cells) and thus they enter the lymph capillaries- then they
reach the local lymph nodes. Wherever they go the malignant cells start multiplying
and finally enter blood stream
 HODGKINS AND NON HODKIN’S LYMPHOMA – ABNORMAL LYMPTPHOCYTES
 Spread of cancer(malignant) cells is called METASTASIS.
 INFECTION OF LYMPH VESSELS is called LYMPHANGITIS
 INFECTION OF LYMPH NODES is called LYMPHADENITIS which can be
 ACUTE –eg GLANDULAR FEVER
 Or
 CHRONIC –eg -TUBERCULOSIS


51. FILARIASIS – WHEN LYMPHATIC VESSELS ARE AFFECTED
– BY A PARASITE WHICH IS BROUGHT BY THE MOSQUIOT
BITE

52. HODGKIN’S AND NON HODGKIN’S LYMPHOMA (TYPE OF
CANCER) - WHEN LYMPHOCYTES MULTIPLY ABNORMALLY
SPECIAL –CELLS
CALLED REED-
STRNBERG CELLS
IN HODGKIN’S
LYMPHOMA

53. IMMUNITY What is Immunity?
Immunity is the ability of the body to defend itself against
disease-causing organisms

55.  Types of Immunity
 There are two major types of immunity:
 Innate Immunity or Natural or Non-specific Immunity.
 The innate immune system provides a general defense
against harmful germs and substances, so it’s also called
the non-specific immune system.
 Acquired Immunity or Adaptive Immunity.
 The adaptive (specific) immune system makes
antibodies and uses them to specifically fight certain
germs that the body has previously come into contact
with. This is also known as an “acquired” (learned) or
specific immune response.

56. INNATE IMMUNITY
 PATHOGEN : A disease-causing organism, including
bacteria,
 Innate immunity refers to the body’s defence
system.
 It is quick
 Non specific

57. 4 BARRIERS- INNATE IMMUNITY
 PHYSICAL barrier
 These include the skin, body hair, cilia, eyelashes, the
respiratory tract, and the gastrointestinal tract. These
form the first line of defence.
 CHEMICAL barriers
 We know that our stomach uses hydrochloric acid to
break down the food molecules. Due to such a strongly
acidic environment, most of the germs that enter our
body along with the food are killed before the further
process is carried on.
 Saliva in our mouth and tears in our eyes also have the
ANTIBIOTIC property that does not allow the growth of
pathogens even though they are exposed all day.
 Cellular barriers : CYTOKINE barriers- Cells
Involved In Innate Immunity- MAST CELLS,
PHAGOCYTES, EOSINOPHILS, DENDRITIC CELLS
etc

58. ACQUIRED IMMUNITY

59. Acquired immunity- takes time and is
specific
 Acquired Immunity
 Acquired immunity or adaptive
immunity is the immunity that our body
acquires or gains over time. Unlike the
innate immunity, this is not present by
birth.
 The ability of the immune system to
adapt itself to disease and to generate
pathogen-specific immunity is termed
as acquired immunity. It is also known
as adaptive immunity.
 Humoral Immune Response humoral
immune response consists of an
antibody produced by the B
lymphocytes.
 Cell-mediated Immune Response
 Cell-mediated immunity is initiated by
the T CELLS- which can be T helper
cells (calls other cells into action ) ,
memory T cells (which remember the
antigen for the next attack) and –
cytotoxic T cells

60. Acquired immunity- humoral immunity
 When a B cell encounters an
antigen, it is stimulated to mature
into a plasma cell or a memory B
cell. Plasma cells then release
antibodies (also called
immunoglobulins, or Ig).
 There are 5 classes of antibodies—
IgM, IgG, IgA, IgE, and IgD.
 Antibodies protect the body in
the following ways:
 ingest antigens (phagocytes)
 Inactivating toxic substances
produced by bacteria
 Attacking bacteria and viruses
directly
 Preventing bacteria and viruses
from attaching to and invading cells
 Activating the complement system -
which has many immune functions

61. SUMMARY

62. END OF CHAPTER –QUESTIONS
 What are components of lymphatic system ?
 Describe importance of Thoracic duct with respect to
LYMPH
 Describe structure of spleen
 Describe structure of Thymus
 Lymph node- short notes
 Cisterna chyli- short notes
 Lymphatic drainage of upper limb
 Lymphatic drainage of head and neck
 Lymphatic drainage of lower limb
 WHAT IS IMMUNITY- ?innate and acquired ?

63. THE END