Lymphoid Tissue Flashcards
What makes a lymphoid organ primary ?
When it produces lymphocytes
What are the two primary lymphoid organs
Thymus and red bone marrow
What are secondary lymphocytes?
Diffuse lymphoid tissue where lymphocytes are activated in response to antigens
__________________ cells are most common where the body meets the outside world
Non-encapuslated
Non-encapsulated diffuse tissue is found where?
GI tract, genitourinary tract, respiratory passages
What is the difference between primary and secondary nodules
Primary nodules are dark in the middle and have a high concentration of naive cells; secondary nodules have a germinal center which is a much paler color and forms a corona
What area are non-stratified squamous cells found in?
Mouth, anus, vagina, respiratory tract
How are germinal centers different than mantles?
Germinal center is pale while the mantle is more dense
Where do memory cells collect in secondary nodules?
Mantle
What cell type is not found in the germinal center?
T cells
What is one example of non-encapsulated lymphoid tissue aggregates?
The tonsils
From most distal to most proximal what are the order of the tonsils?
Pharyngeal, palatine, lingual
What do the tonsils do?
They protected against inhaled or ingested substances
What tonsil section is characterized by large number of stratified squamous cells and 10-20 deep tonsillar crypts?
Palatine
Which two sections of tonsils are most similar?
Lingual and palatine. They both have crypts, stratified squamous epithelium
What tonsils have pseudostratified columnar ciliated epithelium?
Phayngeal
What does MALT stand for? Where is it found?
Mucosa-associated lymphoid tissue
It is in the GI, respiratory airways, and urinary tract
Where is GALT found? What does it stand for?
Gut-associated lymphoid tissue
It is found in the SI particularly the ileum, and it is characterized bu abundance of villi
What are peyers patches associated with?
GALT
The appendix is similar to what?
The peyer’s patches
What are the primary lymph organs?
Thymus and red bone marrow
The thymus is a bilobed structure in the
Mediastinum
When does involution occur and what is it
The process of decreased thymus activity as it becomes filled with adipose tissue
Until puberty
The thymus is made of lobes called ________
Septa
The darker staining region in the thymus is the ______ __________ while the lighter staining area is the the _____ _______
Outer cortex, inner medulla
The ___________________ is the site of t-lymphocyte maturation
Thymic
What cells produce the cytoreticulum?
Cortical (stellate) cells
What cells form the cortical compartment of the thymus
Subcapsular (squamous)
What is tightly packed with whorls of TECs?
Hassall’s copuscles
Where do cytokines that finalize maturation of T cells come from?
Hassal’s copuscles
Where are mature T cells found right before they enter circulation?
Medulla
What are 2 major functions of the spleen?
Reservoir for platelets, recycling center for erythrocytes
Periarteriolar lymphoid sheaths are made of what?
T cells
The most dense zone outside of the GC is the __________
Corona/mantle zone
The transition from white to red pulp is called _______________
Marginal zone
The red pulp is perfused and is in charge of what function?
Blood filtration and erythrocyte turn over
What are splenic cords? What are sinusiods?
Splenic cords are branches of the splenic artery that just dead end.
Sinusiods are barrel like structures made of stave cells that allow blood to flow through
What cleans up the recycled cells that are left in the spleen?
Macrophages
What is swelling made of?
Lymph
What is the function of the hilum in lymph nodes?
The exit for lymph
The outer cortex does what?
Receives lymph from surrounding area
The central medulla is responsible for what?
Collecting lymph on its way to the hilum
Where does blood and lymph meet in the nodes?
Cortex
What are the canals that allow lymph to get deeper into the lymph nodes
Tabeculae
The ____________ ________ is in the lymph node cortex and allows space for lymph to flow
Subcapsular sinus
Where are high endothelial venules found? What cell type are they?
Paracortex, simple cuboidal (allow movement of lymphocytes)
