Lymphatic Tissue and Organs Flashcards
function of the lymphatic system
to eliminate potentially harmful substances in the body
what are the classifications of the lymphatic tissues?
- primary lymphatic tissue- bone marrow, thymus- it is the site of development of lymphocytes into immunocompetent cells
- secondary- site of formation of immunological defense against antigens or pathogens- confrontation with them occur here - lymph nodes, MALT (mucosa associated lymphatic tissue), spleen
MALT
- mucosa associated lymphatic tissue
- GALT- gut associated
- BALT- bronchus associated
- Genital urinary tract
- Tonsils
what do lymphatic nodes do?
what does the spleen do?
what does MALT do?
- filters lymph
- filters blood
- surveillance
How is MALT set up?
- it’s simplest organization is that of a loose lymphatic tissue that is part of the lamina propria (first layer) of the wall of the GI tract, respiratory tract (BALT), or GU tract (genital urinary) where an infection may be present
- cells can be loosely scattered in the lamina propria or have a defined layer
- has reticular fibers that form a supporting framework to suspend cells
what kind of cells are in MALT?
lymphocytes, monocytes, macrophages, plasma cells
what are nodules? what are the two types of lymphatic nodules and how are they different?
-nodules are non-encapsulated. spherical dense aggregations of lymphocytes with some organization
-primary nodules- homogenous -has mostly small lymphocytes
-secondary nodules-has two distinct zones:
corona zone and the germinal center
what are the corona and germinal zones of secondary lymphatic nodules
- Corona (mantle) zone- outer, dark-staining zone containing mature, small sized lymphocytes (mnemonic-to drink corona in the sun, you get tan (dark) and you need to be mature (21))
- germinal center- inner, light staining zone containing IMMATURE (medium/large)
- encounter with an antigen causes the germinal area to swell
how do primary and secondary nodules appear? is this permanent?
- If they are solitary, they are temporary
- If there are a group of them, then they are permanent
Peyer’s Patches
- permanent lymphatic aggregates that contain B and T lymphocytes
- present in the ileum
lymphatic tissue in the appendix
-has permanent aggregations of lymphatic nodules in the lamina propria and the submucosa of the appendix
BALT
- permanent lymphatic aggregates present and in the wall of the bronchi
The pharyngeal, palatine, and lingual tonsils are aggregations of? what kind of lymphocytes reside here?
lymphatic nodules
B lymphocytes
pharyngeal tonsil
where?
type of epithelium?
special structural feature
- “adenoid”
- reside in nasopharynx
- covered by pseudostratified coloumnar epithelium with cilia
- has pleats instead of crypts
Palatine tonsils
where?
what kind of epithelium?
special structural feature?
-pair
-lateral wall of oropharynx
has a partial cap where the tonsil sits
-stratified squamous nonkertainized epithelium
-have multiple lymphatic nodules that have germinal center (where B lymphocytes produced)
lingual tonsils
where?
type of epithelium?
special structural feature?
- small bumps on dorsal posterior 1/3 of tongue
- covered by stratified squamous nonkeratinized epithelium
- has crypts
lymph nodes
- lymphatic organs located along the path of lymphatic vessels
- serve as a filter for lymph before it passes into the blood vascular system
- covered by thin capsule of dense connective tissue
what surrounds the lymph node?
capsule- has fenestrations called trabeculae that extend from the capsule into the lymph node carrying blood vessels and nerves