Rapid Revision: Lymphatic System

Overview

• Secondary Circulatory System: Made up of lymphatic vessels leading into lymph nodes.
• Lymphatic Organs: Spleen, tonsils, thymus are included.

Lymphatic Vessels

• Structure: Blind-ending (have a dead end) and similar to veins.
• Valves: Present in larger vessels to prevent backflow of lymph.
• Movement of Lymph: Requires contraction of skeletal muscles.
• Main Vessels:
  • Right lymphatic duct
  • Thoracic duct

Lymph

• Composition:
  • Similar to tissue fluid or extracellular fluid.
  • Mostly water.
  • Contains proteins, waste products (e.g., CO2, bacteria, cancer cells).
  • White blood cells and products of fat digestion.
• Color Change: Turns white and creamy with fat digestion products.

Lymph Nodes

• Function: Filter lymph to trap pathogens and cancer cells.
• Components:
  • House white blood cells (lymphocytes, B cells, T-cells, macrophages).
  • Lymphocytes proliferate and produce antibodies.

Functions of the Lymphatic System

• Return Excess Fluid: To the blood.
• Return Proteins: Maintains osmotic balance.
• Defense: Against infection or disease.
• Transport Lipids: From small intestine to the blood (left subclavian vein).

Study Recommendations

• Watch detailed videos and use textbooks for comprehensive understanding.
• Practice exam paper questions on this topic.

Note: This is a rapid overview; deeper study is recommended.