Lymphatic System: Anatomy, Flow, and Lymphocytes

Quiz-style flashcards covering lymphatic capillaries, vessels, nodes, ducts, flow direction, lymphedema, and lymphocyte types (T, B, NK) within the lymphatic system.

Where do lymphatic capillaries begin and what do they collect?

They begin as lymphatic capillaries that collect interstitial fluid (lymph) from tissues.

What structural feature of lymphatic capillaries allows large particles to enter?

Overlapping endothelial cells forming one-way flaps that let large molecules and cells in.

How does lymph move through lymphatic vessels and why is movement unidirectional?

Lymph moves via one-way valves and skeletal muscle contractions toward the heart; valves prevent backflow.

What are the levels after capillaries in the lymphatic network, from smallest to largest?

Lymphatic vessels, then lymphatic trunks, then lymphatic ducts.

What is the function of lymph nodes in the lymphatic system?

Purification centers that filter and clean lymph as it passes.

What are the two main lymphatic ducts and what areas do they drain?

Thoracic duct (drains roughly ¾ of the body) and right lymphatic duct (drains the upper right quadrant).

Into which veins do the thoracic duct and the right lymphatic duct drain lymph back into the bloodstream?

Thoracic duct drains into the left subclavian vein; right lymphatic duct drains into the right subclavian vein.

What happens to lymph as it passes through multiple nodes on its way back to the blood?

It is purified repeatedly by successive nodes, becoming very clean.

What condition results from blocked lymph flow and why is it potentially dangerous?

Lymphedema — swelling from lymph accumulation, with risk of infection due to trapped waste.

Where do lymphatic vessels run relative to arteries and veins, and what drives their movement?

They run alongside arteries and veins and rely on one-way valves and skeletal muscle movement to push lymph forward.

What is the final step of the lymphatic path called—the end point before the heart?

Purified lymph returns to the bloodstream via the subclavian veins, joining the blood near the heart.

What are the three main types of lymphocytes?

T cells, B cells, and Natural Killer (NK) cells.

What is the role of cytotoxic T cells?

Cell-mediated killing; they destroy infected or abnormal cells.

What is the role of B cells?

Produce antibodies that target pathogens and help eliminate them.

What are Natural Killer (NK) cells and how do they function?

Innate killers that destroy infected or abnormal cells without antibodies; patrol tissues.

Where do natural killer cells mature?

In the red bone marrow.

Where do T cells mature?

In the thymus after leaving the bone marrow.

Where do most lymphocytes reside and what is acquired immunity?

Most are in lymphatic tissue; acquired immunity is the adaptive response involving T and B cells developed after exposure.

What is the origin of all lymphocytes?

Hematopoietic stem cells in the red bone marrow.

How is lymph drainage divided between the thoracic duct and the right lymphatic duct?

The thoracic duct drains the majority (about ¾) of the body; the right lymphatic duct drains the upper right quadrant.