Lymph definition ,formation and factors affecting lymph flow including applied aspects.

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 Hydrostatic pressure of blood  ( + ) Osmotic pressure of interstitial fluid  ( + ) Oncotic pressure (osmotic press of blood due to pl.prtns )  ( -- ) Tissue hydrostatic pressure  ( -- ) Balance b/w these pressures determine net filtration.

5. STARLING FORCES

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

7. 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

8. 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.

9. 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 .

10. 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

11. 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-,po 4.

12. SLO 3 LYMPH FLOW

13. LYMPH FLOW FROM THE TISSUE

14. SLO 4 LYMPHATIC SYSTEM

15. 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 .

16. 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.

17. 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.

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

19. 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

20. 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

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

22. SL0 5 APPLIED PHYSIOLOGY LYMPHADENOPATHY OEDEMA CHYLURIA CHYLOTHORAX

23. 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

24. 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.

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

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

27. INCREASED FILTRATION

28. 1.Increased capillary hydrostatic pressure Raised venous pressure – heart failure failure of venous pumps. venous obstrn Venular constriction Increased ECF volume – renal failure Decreased arteriolar resistance – excessive heat, vasodilator drugs

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

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

31. DECREASED REMOVAL

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

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

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

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

36. 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.

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

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

39. 4.Chylothorax Lymph from small intestine accumulates in pleural cavity

40. Thank you