Lymphatic System and Lymphoid Organs and Tissues

This set of flashcards covers key concepts and facts about the lymphatic system and lymphoid organs, including their structures, functions, and clinical significance.

What are the three main parts of the lymphatic system?

Network of lymphatic vessels, lymph, and lymph nodes.

What is lymph?

Fluid in lymphatic vessels.

What is the primary function of lymphatic vessels?

To return fluids leaked from blood vessels back to the blood.

What is the role of lymph nodes?

To cleanse lymph by trapping and destroying foreign objects.

What are the key structures of the lymphatic system?

Spleen, thymus, tonsils, lymph nodes, and other lymphoid tissues.

Where are lymphatic capillaries absent?

Bones, teeth, and bone marrow.

What special structures are found in lymphatic capillaries?

More permeable endothelial cells and minivalves.

What do lacteals do?

Specialized lymph capillaries that absorb digested fat and deliver fatty lymph to the blood.

What are the two large lymphatic ducts?

Right lymphatic duct and thoracic duct.

How is lymph propelled through the lymphatic system?

By skeletal muscle action, pressure changes during breathing, and contractions of smooth muscle.

What is lymphedema?

Severe localized edema caused by the obstruction of normal lymph return to blood.

What are the two main types of lymphocytes?

T cells (T lymphocytes) and B cells (B lymphocytes).

What is the function of T cells?

Manage immune response and attack infected cells.

What do B cells produce?

Plasma cells that secrete antibodies.

What are the primary lymphoid organs?

Red bone marrow and thymus.

What are the secondary lymphoid organs?

Lymph nodes, spleen, MALT (mucosa-associated lymphoid tissue), and diffuse lymphoid tissues.

What are the functions of lymph nodes?

Cleansing lymph and offering a site for lymphocyte activation.

What is the germinal center in a lymph node?

Area in the cortex containing dividing B cells.

What is the spleen’s role in the immune system?

Site of lymphocyte proliferation and immune surveillance.

What occurs in the red pulp of the spleen?

Destruction of old blood cells and bloodborne pathogens.

What are the components of the thymus?

Outer cortex with lymphocytes and inner medulla with fewer lymphocytes and thymic corpuscles.

What is the role of Peyer’s patches?

Destroy bacteria and generate memory lymphocytes.