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Purpose of the Lymphatic System

Maintains fluid balance, absorbs fats and vitamins from the digestive tract, and defends the body by housing immune cells.

Lymph

A clear, slightly yellowish fluid derived from interstitial fluid, containing water, proteins, lymphocytes, macrophages, cellular debris, and sometimes pathogens.

Lymphatic Vessels

Tubes that collect lymph, beginning with lymphatic capillaries and merging into larger vessels, including lymph nodes and ducts.

Lymphatic Capillaries

Microscopic, blind-ended tubes located in almost every tissue except some areas, allowing interstitial fluid entry but preventing exit.

Collecting Lymphatic Vessels

Larger vessels that collect lymph from capillaries and contain valves to prevent backflow.

Lymph Nodes

Small, bean-shaped structures that filter lymph as it flows through the lymphatic system.

Lymphatic Trunks

Larger vessels that drain lymph from specific body regions, such as jugular and subclavian trunks.

Right Lymphatic Duct

Drains lymph from the right upper limb, right side of the head and thorax into the right subclavian vein.

Thoracic Duct

Drains lymph from the rest of the body into the left subclavian vein and begins as the cisterna chyli in the abdomen.

Structure of Lymphatic Capillaries

Thin walls of overlapping endothelial cells without a basement membrane, allowing flexibility during tissue swelling.

Function of Anchoring Filaments

Connect lymphatic capillaries to surrounding tissue, pulling openings wider during tissue swelling.

Flow of Lymph

Moves in a one-way direction toward the heart, assisted by skeletal muscle contractions and breathing movements.