Lymphatic Tissue and Organs Flashcards
Primary lympathic tissue
site of development of maturation of lymphocytes into immuncompetent cells
Two kinds of primary lymphatic tissues
bone marrow
thymus
3 kinds of secondary lymphatic tissue
lymph nodes
MALT
Spleen
Function of secondary lymphatic tissues
confrontation with antigens of pathogens occurs here
Lymph Nodes
filter lymph
MALT
surveillance
Spleen
filters blood
largest lymphatic organ
site of B and T lymphocyte proliferation
perpetual graveyard for cells
GALT
gut associated lymphatic tissue
in lamina propria of GI tract
BALT
bronchus associated lymphathic tissue
located in lamina propria of respiratory tract
GU tract
found in lamina propria of gentiourinary tract
Lamina Propria
latin for first layer
loose CT just inside epithelium
What cell types are seen in diffuse lymphatic tissue
lymphocytes
monocytes
macrophages
plasma cells
Solitary Lymphatic Nodules
are temporary
Aggregates of Lymphatic Nodules
are permanent. ex) peyer’s patches, appendix, BALT
Tonsils
aggregates of Lymphatic Nodules with B-lymphocytes
How can you tell it’s a palatine tonsil
- stratified, squamous, nonkeratinized epithelium
- secondary lymphatic nodules
- crypts
- cap made of dense irregular collagenous CT
Regions of lymph nodes
cortex and medulla
Convex surface of lymph vessel
where lymph vessels bring lymph to the lymph node
Concave surface of lymph vessel
bottom surface
has hilum
Sinuses
pathogens and toxins are filtered out here
Lymph node parechyma
cellular part
Where are B lymphocytes found
nodules/cortex
Where are T lymphocytes found
paracortex
2 sources of lymphocytes
high endothelial venules in paracortex (main source)
afferent lymph vessels
Where do T lymphocytes mature
thymus.
but originate in bone marrow
Where are the most immature cells found
outer layer of cortex
Where are the most mature cells found
inner layer of cortex
Medulla
innermost layer where mature, immocompetent lymphocytes reach after tehy travel through the cortex
What does the thymus NOT have?
- afferent lymphatic vessels
- 3D reticular fiber framework
- lymphatic nodules
- B-lymphocytes
- sinuses or sinusoids
Type I Epithelioreticular cells
create an antigen proof compartment for the T-lymphocytes in the cortex
Blood Thymus barrier
isolates T-lymphocytes of the cortex from macromolecules circulating in the blood
What is the blood thymus barrier made of?
cortical capillary endothelium
basal lamina
macrophages
type I epithelioreticular cells
Type VI epithelioreticular cells
form hassall’s corpuscles in the medulla
Type II epithelioreticular cells
form a 3D reticulum with their cell processes to suspend T-lymphocytes in the cortex
Type III epithelioreticular cells
isolate cortex from medula
Type IV epithelioreticular cells
similar to type III
found at corticomedullary junction, isolating cortex from medulla
Type V epithelioreticular cells
similar to type II
form a 3D reticulum with their cell processes to suspend T-lymphocytes in the medulla
DiGeorge’s Syndrome
developmental disorder
cannot produce T lymphocytes
death from infection
What is parenchyma of spleen divided into
red pulp (majority is this) and white pulp (smaller islands formed by lymphatic islands)
Red Pulp Cord (Cord of Billroth)
contains macrophages
Open circulation of spleen
arterial capillaries end near the sinusoids, and blood from these capillaries seeps into splenic cords and then into splenic sinus
