4.8 Lymphoid tissues and lymphatics Flashcards
what are the primary and secondary lymphatic organs?
Primary: bone marrow, thymus
secondary: lymph node, spleen
______ produces all multipotential lymphoid stem cells. ______ cells mature here and ____ cells migrate to the thymus
Bone marrow
B-cells
T-cells
The _____ is the site of T lymphocyte maturation
Thymus
When epithelial reticular cells die, they become _____
Hassells corpsucles
does final maturation occur in the thymus?
no, final maturation occurs in secondary organs
_____ is the only route by which cells enter and exit the thymus
blood
The ________ filters substances that travel through the lymphatic fluid, and contain lymphocytes (white blood cells) that help the body fight infection and disease.
lymph nodes
the _____ is the largest secondary lymphoid organ and is posterior to stomach
spleen
how does the spleen have a dual function?
It has both red and white pulp
- Red- filters blood of aged or abnormal RBC
- White- site of immune response for blood borne antigens
difference between lymphatic system and general circulation?
- The Blood vascular system pumps and carries blood with O2, CO2, electrolytes, hormones and metabolites.
IT also carries lymphocytes to spleen - The Lymph vascular system filters tissues fluid (lymph) through lymph nodes and returns lymph to BVS via thoracic duct
_____ are similar, but thinner than same size veins. They are often found next to circulatory vessels
lymph vessels
You can see lymphocytes but not RBC in lymph vessels. Lymph vessels stain blue with eosin.
First true second false
First false second true
both true
both false
First true, second false
Lymph vessels stain pink with eosin
______ have very thin endothelium and begin as close ended vesicles
lymphatic capillaries
Lymphatic capillaries have Zona Occludens between cells. They also have a discontinuous basal lamina and microfibers that anchor vessels to surrounding CT
first false second true
first true second false
both false
both true
BOTH false
Lymphatic capillaries do NOT have zona occludens between cells. They do have a discontinuous basal lamina, but microFIBRILS attach to surrounding CT, not microfibers
What are the two different sections of a lymph node?
Cortex, medulla
What does the outer cortex consist of?
- Network of reticular cells/fibers, meshwork populated by B-cells
- spherical structures called nodules (follicles)
- primary and secondary nodules
Primary nodules have naive T lymphocytes, while secondary nodules have germinal centers with B cells differentiating into plasma cells
First true, second false
First false, second true
both true
both false
First false, second true
Primary nodules have naive B cells, not T cells. but second is true!
The _____ cortex is rich in lymphocytes with few nodules
primary
recognize outer vs Inner cortex
left is outer, right is inner
The ____ consists of cords interspersed with sinuses
medulla
Medullary _______ are irregular extension of the inner cortex containing B lymphocytes and some plasma cells, while medullary ______ are irregular dilated spaces containing lymph
Cords, sinuses
Medullary sinuses secrete medullary cords. Medullary sinuses are partially lined by reticular cells and macrophages
First true, second false
First false, second true
Both false
both true
Both are true
How does lymph travel from tissues to hilum?
Afferent lymphatic vessels receive lymph from tissues → lymph passes through trabecular sinuses and reaches medullary sinuses → lymph is collected by efferent lymphatic vessels at the hilum
_____ is the dense CT that surrounds lymph nodes. The ______ is the loose network of macrophages, reticular cells and fibers that Communicates with medullary sinuses through trabecular sinuses
capsule, subscapular sinus
What are the MALTs?
Adenoids, tonsils
*you drink a MALT after you get your tonsils removed!*
____ are aggregates of incompletely encapsulated lymphoid tissue, usually associated with the epithelium
tonsils
what are the different types of tonsils?
palatine, lingual, pharyngial
What are the GALTs?
Peyers patches, appendix
_______ are groups of well-organized lymphoid follicles located in the lamina propria and submucosa of the distal portion of the small intestine
peyers patches
______ is the small finger-shaped pouch of intestinal tissue located between the small intestine (cecum) and large intestine (colon), fxn unknown
the appendix
what are the arrows in this pic pointing at? Where is this located?
Peyers patches (in small intestines)
What are the arrows in this picture pointing at?
lymphatic nodules of appendix
______ are unencapsulated lymphoid tissues and lymphoid aggregates (nodules) that monitor for foreign substance between the internal and external environment
MALTs (mucosa associated lymphoid tissue)
