includes anatomical and physiological aspects of lymph

1. LYMPH
Dr . LEKSHMI PRIYA J S
JR

2. SPECIFIC LEARNING OBJECTIVES
• LYMPH FORMATION
• COMPOSITION OF LYMPH
• LYMPHATIC SYSTEM
• LYMPH FLOW
• APPLIED ASPECTS- PATHOLOGY

3. SLO – 1
LYMPH FORMATION
• CAPILLARY FILTRATION
 major route of transport of fluid b/w
intravascular fluid( blood) and extra vascular
fluid ( fluid in interstitial space )
Occurs because of the difference in various
pressures

4. • 2 pressures promote filtration & 2 pressures
oppose filtration
1. Hydrostatic pressure of blood  ( + )
2. Osmotic pressure of interstitial fluid ( + )
3. Oncotic pressure (osmotic press of blood due to
pl.prtns)( -- )
4. Tissue hydrostatic pressure  ( -- )
Balance b/w these pressures determine net
filtration.

5. STARLING FORCES
1. Capillary hydrostatic pressure(Pc)- forces fluid outward through capillary
membrane
2. Interstitial fluid pressure(Pif)- force fluid inwardthroughthe capillary
membrane
3. Plasma colloid osmotic pressure(∏p)- osmosis of fluid inward through
capillary membrane
4. Interstitial fluidcolloidosmotic pressure(∏if)- osmosis of fluid outward

7. NET FILTRATION
Pressure diff :
At arteriole end = [(37-1)-25] = 11 mmHg;OUTWARD
At venule = [(17-1)-25] =- 9 mmHg; INWARD

8. • Net filtration pressure(NFP)= k[(Pc-Pif)-(∏p-∏if)]
• If NFP +ve, fluid filtration occurs across the capillary membrane
• If NFP –ve, fluid absorption into capillaries
• Usually NFP +ve
• Pc-capillary pressure
• Pif-interstitial fluid pressure
• ∏p-plasma colloid osmotic pressure
• ∏if-interstitial fluid colloid osmotic pressure
• k= capillary filtration coefficient, proportional to permeability of
capillary wall and area available for filtration; varies in different
tissues

9. • About 2 units of fluid are left in the interstitial
tissue space as the outward filtration at
arteriolar end is 2mmhg more than the inward
filtration at venular end.
• Usually taken up by lymphatics in interstitial
space,which is again brought back to
circulation as lymphatics finally drain to veins.

10. LYMPH
• Most of the fluid filtered at the arterial end of
capillary is reabsorbed at its venous end .
• Remaining 10% enters circulation through
lymphatics and is called LYMPH .
• LYMPH IS A TRANSUDATE FORMED FROM BLOOD
IN TISSUE SPACES .
• Ie, it is derived from interstitial fluid .

11. LYMPH PLASMA
Flows thru lymph vessels Flows thru blood vessels
Protein content 2-6 g% 6-8g%
Less coagulation factors,clots
slowly
Clots rapidly
Wbc count 1000-2000/cu mm 4000-11000/cu.mm
Fat content more Less

12. SLO 2
COMPOSITION OF LYMPH
• 94% WATER
• 6% SOLIDS
• Composition similar to that of plasma
• Protein content lower than plasma and depends on area it drains
• Fat content is more
• Cells chiefly lymphocytes
• Carbohydrates less than that of plasma
• Clotting factors
• Ions :Na+,k+,ca2+,Cl-,po4.

13. SLO 3
LYMPH FLOW

14. LYMPH FLOW FROM THE TISSUE

15. SLO 4
LYMPHATIC SYSTEM

17. LYMPHATIC CAPILLARIES
• Found in most places that contain capillaries .
• Exception :
bonemarrow,cartilage,cns,cornea,nail,spleen .
• More permeable than blood capillaries.
• Nature of lymphatic capillaries allow WBC s ,
pathogens & cancer cells to enter easily .

20. Lymphatic collecting vessels
• Capillaries join together to form lymphatic
collecting vessels
• Morphologically similar to veins, except
contain more valves
 3 coats
Valves give beaded appearance
• Pass through lymph nodes
• Can be superficial or deep.

21. LYMPH NODES
• b/w two lymphatic collecting vessels
• Capture foreign material
• Site of lymphocyte production
• Become inflamed/engorged with infectious
material
• Can be found in large clusters in
inguinal,cervical & axillary region.

22. Lymphatic ducts
• Collecting vessels end up as either right or left
lymphatic duct.

23. Functions of lymph flow
• Return proteins from tissue spaces to blood.
• Absorption of nutrients
• Act as a transport mechanism
• Supplies nutrients & oxygen
• Role in defense mechanism
• Large enzymes like lipases reach circulation
thru lymphatics

24. MECHANISM OF LYMPH FLOW
• INTRINSIC LYMPHATIC PUMP
• PUMPING BY EXTERNAL COMPRESSION OF
LYMPHATICS
• NEGATIVE INTRATHORACIC PRESSURE
• SUCTION EFFECT OF HIGH VELOCITY BLOOD
FLOW
• INTERSTITIAL FLUID PRESSURE
• INCREASE IN CAPILLAY SURFACE AREA
• INCREASE IN CAPILLARY PERMEABILITY
• INCREASE IN FUNCTIONAL ACTIVITY OF TISSUE

26. LYMPHAGOUGES
• Substances that increases the flow of lymph.
• Eg:
Sunlight
Warmth
Histamine
Dionin

28. SL0 5
APPLIED PHYSIOLOGY
1. LYMPHADENOPATHY
2. OEDEMA
3. CHYLURIA
4. CHYLOTHORAX

29. 1.Enlarged lymph nodes
Lymphadenopathy
 Lymphadenopathy refers to one or more enlarged lymph
nodes.
 Small groups or individually enlarged lymph nodes are
generally reactive in response to infection or inflammation.
This is called local lymphadenopathy.
 When many lymph nodes in different areas of the body are
involved, this is called generalised lymphadenopathy.
Generalised lymphadenopathy may be caused by c/c
infns,connective tissue diseases,malignancies

30. 2.Edema
• In certain pathological conditions there is
Accumulation of free fluid in excess in
interstitial tissue spaces
• Accumulate in dependent parts of body
• Intracellular edema- due to increased ICF
• Extracellular edema- due to increased fluid in
interstitial spaces.

31. Intracellular edema
• Depression of metabolic systems of tissues
• Lack of adequate nutrition to cells
• Inflammation

32. Extracellular edema due to
* increased filtration of fluid into
interstitial tissue space
* decreased removal of fluid
from interstitial tissue space

33. INCREASED FILTRATION

34. 1.Increased capillary hydrostatic pressure
 Raisedvenous pressure –
• heartfailure
• failure of venous pumps.
• venous obstrn
Venular constriction
IncreasedECF volume – renal failure
Decreasedarteriolar resistance – excessive heat, vasodilator drugs

35. 2. Decreased oncotic pressure
• Protein loss in urine– nephrotic syndrome
• Protein loss fromdenuded skin areas- burns, wounds
• Failure to produce protein- liver cirrhosis, malnutrition
• Applied aspect – edema in malnutrition, liver disease, renal
disease

36. 3. Increased capillary permeability
• Action of chemical substances
• Bacterial toxins
• Vitamin deficiency
• Prolonged ischemia

37. DECREASED REMOVAL

38. Decreased lymph drainage
• Lymphedema
• Due to:
• Lymphangitis
• Surgery – radical
mastectomy
• Infection – filariasis/
elephantiasis

39. Classificn OF EDEMA
• Localised-commonly inflammatory
• Generalised-malnutrition, renal diseases

40. • Pitting –inflmmn,ccf,renal disease
• Non pitting-late filariasis,myxedema

41. • UNILATERAL-
DVT,CELLULITIS,LYMPHOEDEMA,MALIGNANCY
• BILATERAL –MEDICATIONS,SYSTEMIC
DISEASES(cardiac,renal,hepatic,pulmonary)

44. Safety factors that px edema
• Low compliance of the interstitium when the
interstitial fluid pressure is in the neg press.
Range
• Ability of lymph flow to increase 10- 50 fold
• Wash down of interstitial fluid prtn concn
which reduces interstitial fluid colloid osmotic
pressure as capillary filtration increases.

45. • Effusion – edema fluid collecting in the
potential spaces like pleural, pericardial,
peritoneal cavities

46. 3.Chyluria
• Excretion of milky urine
• Lymph from small intestine is excreted into
urine

47. 4.Chylothorax
• Lymph from small intestine accumulates in
pleural cavity

48. Thank you