09 The Lymphatic and Immune Systems Free Online FlashCards

What are the two main functions of the lymphatic system?

It returns excess tissue fluid to the blood and helps defend the body against infection.

When does interstitial fluid become lymph?

Interstitial fluid is the fluid around cells. Once it enters a lymphatic vessel, it is called lymph.

How are lymphatic capillaries structured to collect material from tissues?

They begin as tiny, blind-ended vessels in tissues. Overlapping endothelial cells allow fluid, proteins, particles, and some immune cells to enter.

What do intestinal lacteals absorb and transport?

Lacteals absorb dietary fats in the small intestine and carry them in lymph.

What helps move lymph when it has no central pump?

Skeletal-muscle contractions, breathing movements, and contractions of vessel walls help propel lymph toward the chest.

Which regions do the thoracic and right lymphatic ducts drain?

The thoracic duct drains most of the body; the right lymphatic duct drains the right upper region. Both empty into veins near the jugular and subclavian vein junctions.

Where do B cells and T cells mature?

Bone marrow produces blood cells and is where B cells mature; T cells mature in the thymus.

Name examples of secondary lymphoid organs and tissues.

Lymph nodes, the spleen, tonsils, and gut-associated lymphoid tissue such as Peyer’s patches are secondary lymphoid organs or tissues.

How do lymph nodes support immune responses?

They filter lymph from tissues. Immune cells can capture foreign material there, while B and T lymphocytes encounter antigens and may become activated.

What does the spleen monitor and filter?

The spleen filters blood and helps immune cells respond to blood-borne threats; it is not a filter along lymphatic vessels.

What characterizes innate immune defenses?

Innate defenses respond rapidly and broadly. Barriers, phagocytic cells, natural killer cells, and inflammation contribute to this defense.

What can B cells become, and what do those cells produce?

B cells can become plasma cells that produce antibodies, which bind specific targets.