2012B11 Outline the important features of the lymphatic circulation.



·         Lymph composition

·         Anatomy

·         Physiology


Lymph composition:

·         Water

·         Electrolytes

·         Protein (almost from liver due to permeable sinusoids - total 20g/L, hepatic 50g/L)

·         Fat (almost all from gut via cisterna chyli)

·         Carbohydrate

·         Immune cells (antigen-presenting cells including dendritic cells, macrophages)

·         All coagulation factors (but low level of fibrinogen)




·   Located in all tissues except bone, cartilage, brain

·   Three layers: intima, media, adventitia

·   Anti-reflux valves

·   Superficial lymphatics travel with veins

·   Deep lymphatics travel with arteries


·   Right lymphatic duct: drains RUL, R H&N, R hemithorax

·   Thoracic duct: drains everything else (N.B. Virchow’s node in supraclav fossa)

Lymph nodes

·   Large groups in axilla, inguinal, cervical regions (for UL, LL, H&N respectively), abdomen

·   Cisterna chyli: dilated sac at the lower end of the thoracic duct (for GIT)




·   Extrinsic pump: compression by skeletal muscle or arterial pulsation

·   Intrinsic pump: smooth muscle

·   Valves ensure unidirectional flow

·   Production: 8-12L/day (↑if exercise, capillary leak e.g. sepsis, anaphylaxis)

·   Reabsorption: 4-8L/day via LNs; 4L/day via ducts (↓ if lymphoedema, radiation, obstruction)

Role in health

·   Return extravasated fluid and protein to circulation, minimise oedema

·   Transport ingested fat to circulation (bypass liver -> prevent fatty liver)

·   Transport antigen-presenting cells to lymph nodes

·   Formation of concentrated urine: removal of protein-rich ISF from medulla, allows water to enter vasa recta, preserves osmotic gradient

Role in disease

·   Lymphoedema

o Destruction e.g. surgery, radiation

o Obstruction e.g. tumour




Feedback welcome at ketaminenightmares@gmail.com