Lymphoid Tissue Histology 1 (non-encapsulated) Flashcards
the two kinds of classification of lymphoid tissue
1) functional 2) capsular
Capsular classification: Non-encapsulated
Diffuse and Nodular
Nodular Types
Single and Aggregate
Single (Nodular)
Primary and Secondary nodules
Aggregate (Nodular)
Tonsils, payer’s patches, vermiform appendex
Non-encapsulated – nodular aggregate – tonsils
Pharyngeal, Palatine, Lingual
Primary lymphoid organs produce
the cellular components of the immune system
Secondary lymphoid organs are where
immune responses occur
Non-encpasulated Diffuse lymphoid tissue is located where
diffusely scattered deep to the epithelium in connective tissue
strategically located in GI, genitourinary, respiratory tracts
Nonencapsulated –nodular single –primary
Far more infrequent than secondary
consists of only small lymphocytes, prenatal, does not possess a germinal center
Nonencapsulated– nodular single – secondary
far more prevalent than primary nodules
possess dark staining germinal center
i. germinal center lighter than mantle
ii. outer ridges darker (mantle), location of memory
cells, small lymphocytes
possesses clusters of lymphocytes
memory cells are located in the
outer ridges of the nonencapsulated single nodular secondary nodule lymphoid tissue
lymphoblasts are located in the
nonencapsulated single nodular secondary nodule germinal center lymphoid tissue
tonsils
non-encapsulated aggregate nodular lymphoid tissue
partially encapsulated aggregates of nodular tissue
Deep to the mucosa of the nasopharynx, oral cavity and oropharynx
lymphocytes penetrate the epithelium
tonsils (pharyngeal)
also called adenoids
non-encapsulated aggregate nodular lymphoid tissue
pharyngeal tonsil
characterized by pseudostratified ciliated columnar epithelia
possesses a germinal center
tonsils (palatine)
non-encapsulated aggregate nodular lymphoid tissue
characterized by stratified squamous epithelia
possesses germinal centers
possesses 10-15 epithelial invaginations called crypts
tonsils (lingual)
stratified squamous epithelium
no well defined capsule
posses germinal centers
one crypt/tonsil
Palatine tonsil
- location
- number per/person
- # of crypts/tonsil
- epithelium
- capsule type
- lateral walls of oral cavity
- 2
- 10-20
- non-keratinized stratified squamous epithelia
- thick, partial CT
Pharyngeal tonsil
- location
- number per/person
- # of crypts/tonsil
- epithelium
- capsule type
- posterior of oropharynx
- 1
- 0
- ciliated pseudostratified columnar epithelia
- thin, partial CT capsule
Lingual tonsils
- location
- number per/person
- # of crypts/tonsil
- epithelium
- capsule type
- posterior 1/3 of the tongue
- small/numerous
- 1
- stratified squamous
- no definitive capsule
MALT
what, where, cluster type
Non-encapsulated lymphoid tissue
aggregate nodular tissue
mucosa associated lymphoid tissue (MALT)
single OR clusters of lymphoid nodules
typically found in the gastrointestinal tract, respiratory tract, respiratory passageways and urinary tract
MALT: GALT
what, where, other names, characterization, single/cluster
epithelia traits
“gut associated lymphoid tissue”
in ileum they are called “peyer’s patches”
- characterized by an abundance of villi
- single or clusters of lymphoid tissues
- characterized by simple columnar epithelium with goblet cells
- crypts present
GALT in the vermiform appendix
No villi
characterized by crypts
characterized by simple columnar epithelium w/goblet cells
what’s the difference between GALT in the ilium and the vermiform appendix?
the GALT in the vermiform appendix lacks villi
so it’s simple columnar epithelium with goblet cells, crypts
GALT in the ilium is referred to as “peyer’s patches”
