This document discusses the lymphatic system in the orofacial region. It begins by describing lymphatic tissues and lymph flow from tissues. The lymphatic system consists of lymph, lymphatic vessels, lymph nodes, lymphoid organs, and diffuse lymphoid tissues. Lymph nodes in the head and neck filter lymph and activate lymphocytes. The major lymphoid tissues in the orofacial region are the tonsils, which form Waldeyer's ring to protect the oropharynx. Lymph drainage from different areas of the head and neck flows to specific superficial and deep cervical lymph nodes.

1. LYMPHOID TISSUES AND
LYMPHATICS IN OROFACIAL
REGION

2. • Body made up of variety cells organized as tissues
and organs
• Tissue bathed in tissue fluid nutrients, blood,
waste materials
• Part of tissue fluid returns back to cardiac
circulation
• 1/10th carried by lymphatics
 through walls of lymphatic capillaries become
lymph and carried by lymphatic vessels
*

3. LYMPHATIC SYSTEM CONSISTS:
1. Lymph – clear fluid
2. Lymphatic channels : vessels, capillaries, ducts
3. Lymph nodes
4. Lymphoid organs
5. Diffuse lymphoid tissue
6. Bone marrow

4. CELLS OF LYMPHATIC SYSTEM:
Lymphocytes
T – lymphocytes plays vital and central role in all lymphoid
tissue!
B – lymphocytes
Natural killer cells
Other type of WBC (leukocytes) : monocyte, macrophage, neutrophils, basophils
Supporting cells – interact with lymphocyte, present antigen to lymphocyte

5. BONE MARROW
2 types of multipotent stem cells
A. Non-lymphoid cells :
differentiate in bone marrow  erythrocytes, granulocytes, monocytes
B. Lymphoid stem cells :
differentiate in bone marrow and then migrate to lymphoid tissues
1. T lymphocytes – based on coreceptor divided into
T – helper cells (with CD4 coreceptors)
T- cytotoxic cells (with CD8 coreceptors)
2. B lymphocytes
-plasma cells
-memory cells

6. LYMPHOID ORGANS
PRIMARY LYMPHOID ORGANS SECONDARY LYMPHOID
ORGANS
Pre T+B  naïve T+B naïve T+B cells settle
Mature in the absence of Ag + leave 2ndary collect Ag from local sites
Lead them to 2ndary  exposure of naïve cells to Ag
Fetal Liver  Activate Ag specific
lymphocytes
Thymus  Activate specific immune
responce
Adult Bone Marrow Lymph Nodes, Spleen
Tonsils
NALT, MALT, GALT

7. FUNCTIONS OF LYMPHATIC SYSTEM
• Tissue drainage  Lymph carries proteins and large particulate matter away from tissue
space
• Fat absorption- only in lymph vessels in intestine  fat + fat soluble material give lymph color
• Protect body against foreign material
• Bacteria, toxins and other removed from tissues
• Important role in redistribution of fluid in body
• Immunity : lymphatic organs + nodes +bone marrow responsible for Production and
maturation of lymphocytes
• T + B cells important role in support of immunity

8. LYMPH NODES
• Lymph nodes act as defence against pathogens and foreign substances – chain of well
organized nodes present in small groups at all strategic locations
• Important and major component of lymphatic system : head and neck
• - 450 lymph nodes general (adult)
• 60-70 found in head and neck (mostly)
• The centre of : Filtration of foreign substances and debris in lymph, act as site for Antigen
presentation + Lymphocyte activation, differentiation and proliferation!!!!
Anatomy:
Yellowish, oval, bean shaped soft and (fish meat appearance)
2-20mm diameter
Each lymph node connected to circulation by Afferent and Efferent lymphatics!!!!

9. 1. Outer aspect covered by capsule composed : collagen,
elastin fibers with few fibroblasts + has a sub-
capsular sinus
2. 3 areas :
. Cortex/corical area
. Paracortex/paracortical area
. Medullary area along with sinuses
3. Lymphoid lobule (radiate from hilus to capsular area
in form of cones) – make up the lymph node (1-2
lobules in small node)
4. Trabeculae extends from cortex to medulla
5. Sinuses reticular
fibers

10. Cortical (follicle) Area:
Area of superficial cortex is made up of lymphoid
follicles with Germinal centre
1. Primary lymphoid follicle (inactive
lymphocytes)
2. Secondary lymphoid follicle – arise from
primary due to antigenic stimuli
peripheral area ( mantle zone)
central area ( germinal centre )
( B cells are seen are differentiate and proliferate)
into plasma cells and long term memory cells

11. Activity in cortical areas requires assistance from other
cells :
• Follicular dendrtic cells : are antigen trapping cells
which keep antigen on their surface and present it to
B cells
• Tingible body macrophages
• Lymphoid cells : mostly B cells
• Centroblasts : give rise to centrocytes
• Centrocytes : further division into immunoblasts
• Lymphoblasts :
• Immunoblasts:

12. Paracortex (paracortical area)
(IS A THYMUS DEPENDENT AREA/zone
with Lymphoid cells)
beneath cortex, and known as deep cortex
1. T lymphocytes
2. Interdigitating dendritic cells : represent bone marrow derived cells,
* important role initiate/ maintain the immune response
3. Epithelioid venules (postcapillary venules, high endothelial venules)
*role recirculation, distribution , homing of the lymphocytes in different lymphoid organs
4. Follicular reticular cells : transport of cytokines +/or antigen through the parenchyma of
lymph node

14. Medullary Area
Is an active site of plasma cell proliferation,
differentiation, and production of Ab
 the cells of medulla form solid chords
(mature plasma cells, lymphocytes, immunoblasts
plasmacytoid lymphocytes)
Which are intervened by medullary sinuses!!
*few macrophages and mast cells present

16. LYMPH SINUSES
Each lobule has a single afferent lymphatic channel
+ every loblule connected by lymphatic sinuses
 Lymph enters lymph node
through afferent vessels
subcapsular sinus
trabecular sinus
transverse sinus
drains into medullary sinus  into a single efferent
vessel

17. IN Boundaries of lobules , Fibroblastic reticular cells +
fibers are formed so we can define and segregates from
sinuses and surrounding cells = RETICULAR
NETWORK
Sinus in medullary area shows presence of FRCS
they form network where
1. Lymphocytes (flow along with lymph in the sinuses)
2. Sinus Histiocytes (remove cell debris)

19. lymphocytes ( which are circulating in bloodstream)
Enter lymph node through arterioles
Migrate into the parenchyma of lymph node once they
reach HEVs =( specialized vessels lined with endothelial
cells)
High endothelial venules and lymphatic vessels play
important role in movement of lymphocytes in the node!!!

20. LYMPHATIC SYSTEM
LYMPH (from Right subclavian vein)
Enters lymph node by Afferent lymphatics vessels
Capillaries in the form of plexus  absorb and collect lymph
(later become larger in diameter= Vessels)
Subcapsular sinus Cortical sinus Trabecular sinus Medullary sinus
Lymph drain into a single vessel Efferent lymphatic vessel (which along with artery+ vein in
hilum)
Transported to Thorasic Duct
Back to Main blood circulation via LEFT SUBCLAVIAN
VEIN)

21. * Sinuses are home to a large number of
macrophages so phagocytic activity occur
*Lymph in there lymph nodes  collect Antigens, active
cells of immune system, and Antibodies that enter lymph
stream!!!!

22. CAPILLARIES HAVE A GREATER PERMEABILITY
THEY SHOW VERY THIN ENDOTHELIAL CELLS 
 THESE ARE ATTACHED TO CONNECTIVE TISSUE BY ANCHORING
FILAMENTS
   PREVENT THE COLLAPSE OF LYMPHATICS LUMENS

23. • lymphatic vessels can be distinguished from vein
by  the presence of small number of lymphocytes in
their lumen and absence of erythrocytes!!!
• Vessel wall:
1. outer fibrous covering
2. middle layer of smooth muscle
3. elastic tissue
4. inner linning of endothelial cells

24. • Lymphatic capillaries and vessels have a
numerous valves along their course,  are better
formed and more in number (than in veins)
Prevent backflow of lymph
• Lymphatic vessels have blind ends (differ
from blood vessels)
system is NOT circulatory
flow is unidirectional

25. LYMPH
• Is a watery fluid, offwhite/ yellowish color
• Composition similar to plasma + almost identical to interstitial
fluid
• Derived from interstitial fluid (tissue fluid) that flows into
lymphatics
• Lymph caries particulate matter in the form of bacteria and
debris
• Also caries absorbed fat( as lymphatic system major route for
absorption of fat)
as lymph passes lymph node, all these partilcles are
almost removed and destroyed

26. COMPOSITION
96% WATER 4% SOLIDS
Protein concetration : 3-5 g/dl
Albumin, globulin, clotting factors ( fibrinogen, prothrombin), enzymes
Depending upon the part of body from which it is collected
Lipids 5-15% -mainly lipoproteins
Carbohydrates –mainly glucose
Electrolytes – sodium, calcium, potassium etc
Cellular content – mainly lymphocytes

27. RATE OF LYPH FLOW
• 100ml /h through thoracic duct
• 20ml/h into circulation total : 120ml/h 2-3 L /day
Intestitial fluid pressure major effect on normal lymph flow  increase pressure, increase flow >20folds
Factors increase formation and lymph flow:
1. Increase capillary pressure
2. Decrease plasma colloid osmotic pressure
3. Increase permeability of the capillaries
4. Compression of lymph vessel skeletal muscles contraction, pulsations of arteries
** during excersise + movement increase flow (20-30 folds)- lympatic pumping very active

28. TONSILS
To protect oropharynx from foreign substances
 TONSILS form lymphatic tissue in a ring 
 WALDEYER’S RING
(interrupted circle of protective lymphoid
tissue)
1. Midline of oropharynx superiorly
= Pharyngeal tonsils
2. Palatine tonsils (bilateral)
3. Posterior 1/3 of the tonque in the floor of
mouth = Linqual tonsils

29. • Each tonsil composed of lymphatic tissues or
nodules
• Each nodule have germinal centres= are active
areas of lymphocyte formation (linqual and
palatine)
• Each tonsil bound externally by a connective tissue
capsule and has underlying mucous/seromucous
associated glands
Epithelium covering:
1. Pharyngeal tonsil: pseudostratified, columnar,
and ciliated epithelium
2. Palatine and linqual : non keratinized stratified
squamous epithelium
The epithelium continuous with clefts or grooves of
tonsils

30. LINQUAL TONSILS
EXTENDS FROM CIRCUMVALLATE PAPILLAE TO THE BASE OF
EPIGLOTTIS POSTERIORLY

31. • A connective tissue  capsule which is covered by
epithelium (non keratinized)
• Mucous glands seen underlying with their ducts
opening into crypts flush and cleanse the area (free of
inflammation
• Skeletal muscle and adipose tissue
• Deep cervical lymph nodes drain into linqual tonsils

33. PALATINE TONSILS
• Are the largest tonsils in Waldeyer’s ring
• Sitted btw palatoglossus muscle and palatopharyngeus
muscle (anterior + posterior pillar)
• Tonsil divided into lobules by the crypts
• Each lobule contains numerous lymphatic nodules witch
contain germinal centre

34. • Long branching crypts- house of oral bacteria
• Seromucous glands Not open into the crypts
but on the surface of glands
lack flushing action lead to frequent
inflammation
• Deep cervical lymph nodes drain

35. PHARYNGEAL TONSILS
• Location : line in the posterior wall of nasopharynx
• Sometimes extends laterally in the area Torus tubarius
(around the opening of auditory tube)  TUBAL
TONSIL
• Retropharyngeal nodes drain the pharyngeal

36. • No crypts
• But many folds in the mucosa
• No well defined lymphoid tissue and
germinal centres (diffuse lymphoid tissue)
• Pseudostratified columnar ciliated
epithelium
• Seromucous glands that drain on the
surface of epithelium
• Deeper : muscles of pharynx and the
periosteum (which attached to the sphenoid
bone)

38. FUNCTIONS:
Provide local immunity
Mechanism prepared for defence
Activate lymphocytes (when microorganisms, bacteria invade )
1. Some lymphocytes transform into T cells  engulf bacteria / discharge substances to destroy
them
2. Other become B cells which differentiate into plasma cells
secrete antibodies  destroy antigen
plasma cells join salivary glands cells secreting secretory IgA
3. Lymphocytes sensed allergens and start process of Ab production  retain the information
 Memory cells !!!

39. LYMPHATIC DRAINAGE OF HEAD AND
NECK
every group of lymph nodes (that are connected by lymphatic vessels) are responsible for the
lymphatic drainage of a particular area
Lymph through lymphatic vessels (from a particular area) drain into lymph nodes
SUPERFICIAL CERVICAL DEEP CERVICAL
anterior cervical nodes superior deep cervical nodes
superficial cervical nodes inferior deep cervical nodes

40. SUPERFICIAL GROUP
Superficial tissues
Regional lymph nodes
Deep cervical nodes
Regional lymph nodes drainage of
superficial tissues!
Occipital nodes
Buccal / facial nodes
Parotid nodes
Submental nodes
Submandibular nodes
Posterior Auricular nodes
Anterior cervical nodes
Superficial cervical nodes

42. SITE NODE EFFERENT
Back of skull Occipital nodes Deep cervical node
Post. external
auditory meatus, part
of scalp above auricle
Posterior auricular
nodes (mastoid)
Deep cervical node
Eyelid, lateral part of
cheek, Anterior wall
of auditory meatus
Parotid nodes Deep cervical node
External nose and
cheek, lower eyelid
Buccal nodes Submandibular node
Upper lip + lower
(except central),
lateral floor of mouth,
ant. 2/3d of tonque
Submandibular nodes Deep cervical
Tip of tonque, central
part of lip, buccal floor
Submental nodes Submandibular node
Skin of head+neck Superficial cervical
nodes
Deep cervical nodes

43. DEEP GROUP
Deeper tissues of head and neck
Regional lymph nodes
Deep Cervical nodes
Regional lymph nodes drainage of the
deeper tissues
Retropharyngeal lymph nodes
Superior deep cervical lymph nodes
Inferior deep cervical lymph nodes
Paratracheal lymph nodes
Infrahyoid nodes etc

44. RETROPHARYNGEAL LYMPH
NODE
Sites (afferent) : hard and soft palate
Nose
Auditory tube

45. SUPERIOR DEEP CERVICAL LYMPH NODES
Location : below posterior belly of digastric
btw angle of mandible and anterior border of
sternocleidomastoid
Afferent : Tongue, tonsils, hard + soft palate
( JUGULODIGASTRIC LYMPH NODES )
INFERIOR DEEP CERVICAL LYMPH NODES
Location : angle btw internal jungular vein and superior
belly of omohyoid
( JUGULAR OMOHYOID LYMPH NODES )

46. UPPER PART  PAROTID LYMPH NODES
MIDDLE PART  SUBMANDIBULAR LYMPH NODES
LOWER PART  SUBMENTAL LYMPH NODES
**deep cervical also called terminal group of lymph nodes
receive the lymph from all vessels of head + neck
** all the lymphatics from head and neck drain into the deep cervical drain
into jugular trunk  ends in thoracic duct!!

47. Lymphatic vessels from median area of lower lip drain
into Submental node (4)
Lip drainage in other area is to  SubMandibular
node (1,2,3)

48. • Tip : submental nodes
• Anterior 2/3rd : submandibular
and then to lower deep cervical
nodes
• Posterior 1/3rd : jugulodigastric
nodes
1. Hard Palate : superior
(jugulodigastric) and
retropharyngeal nodes
2. Soft Palate : retropharyngeal
and superior
3. Floor of mouth : Submandibular
and submental nodes

49. DISCUSSION…..