CH. 24 Lymphatic System Flashcards
Brief overview of the antibody immune response to an antigen.
antigens are substances that bind to components of adaptive immunity and are often perceived as abnormal to the body; if antigens are discovered, lymphatic cells initiate a systematic defense against the antigens, called an immune response. soluble proteins called antibodies are then produced and bind to the foreign agents where they are damaged or identified for other elements of the immune system to attack it.
What is lymph? and describe the network of vessels of which they are composed of.
a liquid mixture that is a combination of interstital fluid, solutes, and sometimes foreign material enter the lymph vessels
(smallest to largest) - lymphatic capillaries, lymphatic vessels, lymphatic trunks, and lymphatic ducts
What are lymphatic capillaries?
microscopic vessels that are close ended tubes and are interspersed among most blood capillary networks;
Differentiate between afferent lymphatic vessels and efferent lymphatic vessels.
afferent lymphatic vessels transport lymph to a lymph node where it is filtered for foreign pathogenic material; efferent lymphatic vessels are where the lymph exits the lymph node once filtered
Explain how lymph is drained in the lymphatic trunks.
left and right lymphatic trunks form from merglng lymphatic vessels and each lymphatic trunk drains lymph from a major body region as follows:
■ Jugular trunks drain lymph from the head and neck.
■ Subclavian trunks drain lymph from the upper limbs, breasts,
and superficial thoracic wall.
■ Bronchomediastinal trunks drain deep thoracic structures.
■ Intestinal trunks drain most abdominal structures.
■ Lumbar trunks drain the lower limbs, abdominopelvic wall,
and pelvic organs.
Where do the lymphatic trunks drain into?
the largest lymph vessels known as the lymphatic ducts where they empty lymph back into the venous circulation
What are the different types of lymphatic cells?
work together to elicit an immune response
1) Macrophages: monocytes that have migrated from the blood into other body tissues; responsible for phagocytosis of foreign substances and may also present antigens to other lymphatic cells
2) Special epithelial cells (also known as nurse cells): occur in thymus and secrete thymus hormones
3) Dendritic cells: occur throughout body’s tissues and internalize antigens and present them to lymphocytes; main antigen presenting cell of the immune system
4) Lymphocytes: most abundant cells in the lymphatic system and migrate through the lymphatic system to search for antigens; three types (T-lymphocytes, B-lymphocytes, and natural killer cells
What are the three types and functions of lymphocytes?
1) T-lymphocytes: lymphocyte plasma membrane of a t-lymphocyte contains a coreceptor that can recognize a particular antigen (main two groups are helper T-lymphocytes and cytotoxic T-lymphocytes)
- Helper T-lymphocytes are needed to begin an effective defense against antigens
- Cytotoxic T-lymphocytes come in direct contact with infected or tumor cells and kill them; kill by secreting substances into abnormal cells that cause unregulated entry of material into the cell and directly triggers cell death
2) B-lymphocytes: contain antigen receptors that respond to one particular antigen and stimulate the production of immunoglobulins, or antibodies, that respond to that particular antigen (differentiates into plasma cells or memory B-lymphocytes)
3) Natural killer cells: tend to have CD16 receptors and can kill a wide variety of infected cells and some cancerous cells
What is lymphopoiesis?
process of lymphocyte development and maturation: lymphocytes can only particpate in immune response once it is immunocompetent, fully able to participate in immune response
What are lymphatic nodules? Further explain mucosa associated lymphatic tissue and tonsils)
ovoid clusters of lymphatic cells with some extracellular connective tissue matric that have a pale center called a germinal center (contains proliferatng B-lymphocytes and some macrophages); filter and attack antigens
MALT: large collections of lymphatic nodules that are located in the lamina propria of the mucosa of several tracts; detect antigens and initiate immune response in presense of certain substances like urine, food, etc in their respective tracts
Tonsils: large clusters of lymphatic cells and extracellular connective tissue matrix that are not completely surrounded by a connective tissue capsule; consist of multiple germinal centers and have invaginated outer edges called crypts that help trap material and facilitate its identification by lymphocytes
What are the main lymphatic organs?
1) Thymus: bilobed organ located in the anterior mediastinum; functions as a site for T-lymphocyte maturation and differentiation
2) Lymph nodes: small, round or ovoid structures located along the pathways of lymph vessels and typically occur in clusters that receive lymph from selected body regions; primary function is to filter antigens from lymph and intiate an immune response when necessary
3) Spleen: largest lymphatic organ in the body; filters blood and recycles aged erythrocytes and platelets; serves as a blood reservoir; houses lymphocytes; mounts immune response to foreign antigens in the blood
