Lympho- reticular system:
- Lymphatic system is auxillary to the venous system.
- It consists of closed system of vessels, the tissue fluid which enters lymphatic system is known as Lymph.
- Helps the venous system to drain colloid and particulate matters of the tissue fluid.
- Helps in absorption of the digested fat.
- Filtration of noxious agents.
- Produce lymphocytes by lymphatic follicles.
- Produce antibodies by plasma cells.
- Lymph vessels - Lymph capillaries, Lymph ducts.
- Lymphoid tissues - Primary lymphatic follicles, lymph nodes, thymus.
Lymph capillaries: These begin blindly in the tissue spaces around the blood capillaries and communicate freely with the adjacent lymph capillaries.·
- Valveless ,devoid of basal lamina and pericytes.
- Permeable to macromolecules, colloids.
- Lymph capillaries cannot collapse during increased pressure.
- This includes Thoracic duct and right lymphatic duct which finally drains into right and left brachiocephalic veins respectively.
- Thoracic duct drains the lymph from the entire body except right side of head and neck, right upper limb, right thoracic wall, right lung, right side of the heart and convex surface of liver.
- Rate of lymph flow is 100ml per hour.
Two type of cells are present:
Fixed cells or Reticular cells: Also known as Littoral cells ,that act as stem cells from which free cells are derived.
Free cells: Consists of lymphoblasts, lymphocytes and plasma cells.
Lymphocytes:
- Again they are of 2 types- thymus dependent cells ,T lymphocytes that are responsible for cell mediated immunity and delayed hypersensitivity reactions.
- And then we have thymus independent cells, B lymphocytes which produce humoral immunity.
- Primary lymph organs- Bone marrow, thymus Secondary lymph organs- Lymph node, Spleen and Tonsil.
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