Brief description of lymphatic system, lymph nodes and lymph

1. LYMPHATIC SYSTEM
AND LYMPH
Dr. JILSHA

2. OBJECTIVES
To get a better understanding of :
 Lymphatic system
 Lymph nodes and their functions
 Formation, Composition and functions of lymph.

3. LYMPHATIC SYSTEM
 It is a closed system of lymph channels or lymph
vessels through which lymph flows.
 One way system – allows lymph flow from tissue
spaces towards the blood.
 Almost all tissues of the body have lymphatics –
except skin, brain and bones.

4. LYMPHATIC SYSTEM
 Lymphatic system arises from tissue spaces as a
meshwork of delicate vessels – lymph capillaries.
 Large lymph vessels ultimately form the right
lymphatic duct and thoracic duct.
 R lymphatic duct – R subclavian vein.
 Thoracic duct – L subclavian vein.

5. LYMPH NODES
 Small glandular structures located in the course of
lymph vessels.
 Each lymph node constitutes masses of lymphatic
tissue covered by a dense connective tissue capsule.
 Three layers – cortex, paracortex and medulla.

6. STRUCTURE OF A LYMPH NODE

7. STRUCTURE OF A LYMPH NODE
 CORTEX
 Primary and secondary follicles.
 Contains B lymphocytes and macrophages.
 PARACORTEX
 Between cortex and medulla
 Contains T lymphocytes.
 MEDULLA
 Contains B and T lymphocytes and macrophages.

8. LYMPH NODES
 LYMPHATIC VESSELS
 Lymph enters lymph node via Afferent vessels.
 Lymph leaves lymph node via Efferent vessels.
 DISTRIBUTION OF LYMPH NODES
 Along the course of lymphatic vessels in elbow, axilla,
groin, knee.
 Also in neck, thorax and abdomen where many lymph
vessels join.

10. FUNCTIONS OF LYMPH NODES
 Filters lymph – water & electrolytes are
removed, proteins & lipids are retained.
 Bacteria and other toxic substances are
destroyed by macrophages.
 Also called defense barriers.

12. APPLIED PHYSIOLOGY
 During infection, lymph node activity increase –
swelling of lymph nodes.
 Tonsillitis, Throat Ca – neck lymph node (cervical
nodes) swelling.
 Breast Ca – armpit - axillary nodes.
 Lung Ca – chest.
 Genital infections – groin - Inguinal nodes.

14. LYMPH
 Lymph is an alkaline clear fluid that is derived
from interstitial fluid and flowing to blood
stream through lymphatic vessels.

15. FORMATION OF LYMPH
 Lymph is formed from interstitial fluid due to the
permeability of lymph capillaries.
 When blood passes through blood capillaries in the
tissues, 9/10th – into venous end to arterial end,
1/10th - into lymph capillaries.
 Composition of lymph = Insterstitial fluid

17. RATE OF LYMPH
 About 120 ML of lymph flows into blood per
hour.
 About 100 ML – thoracic duct.
 20 ML – right lymphatic duct.

18. COMPOSITION OF LYMPH
 Lymph is a clear and colorless fluid.
 96% water and 4% solids.
 Some blood cells are also present.

20. FUNCTIONS OF LYMPH
 Important function – return proteins from tissue
spaces into blood.
 Redistribution of fluid in the body.
 Bacteria, toxins and other foreign bodies are
removed.
 Maintenance of structural & functional integrity of
tissue.
 Intestinal fat absorption.
 Immunity – transport of lymphocytes.

21. SUMMARY
 Lymphatic system is a closed one way system.
 Lymph node is made of cortex, para cortex and medulla,
afferent & efferent vessels.
 Lymph nodes are present in various regions.
 Infection leads to swelling of lymph node.
 Lymph is a clear fluid.
 Lymph flows into the blood at a rate of 120 mL/hr.
 Foreign bodies are removed in lymph.