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Masses of lymphoid nodules comprising tonsils are collected in three general locations in the wall of the pharynx.
(a) Palatine tonsils are located in the posterior lateral walls of the oral cavity, and lingual tonsils are situated along the surface of the posterior third of the
tongue. Both are covered with stratified squamous epithelium. The pharyngeal tonsil is a single medial mass situated in the posterior wall of the
nasopharynx. It is usually covered by ciliated pseudostratified columnar epithelium, but areas with stratified epithelium can also be observed.
Hypertrophied regions of pharyngeal tonsils resulting from chronic inflammation are called adenoids.
(b) A sectionSource:
showing
several14.
lymphoid
nodules
(LN),&collectively
coveredJunqueira’s
by stratifiedBasic
squamous
epithelium
(E) on one side and a connective tissue
Chapter
The Immune
System
Lymphoid Organs,
Histology,
13e
capsule (CT)Citation:
on the other.
Some
nodules
show
lighter
staining
germinal
centers
(GC).
Infoldings
of
the
mucosa
in some
form crypts (C), along
Mescher AL. Junqueira’s Basic Histology, 13e; 2013 Available at: http://mhmedical.com/ Accessed:
Maytonsils
03, 2017
which nodules
are
especially
numerous.
Lumens
of
crypts
contain
desquamated
epithelial
cells,
live
and
dead
lymphocytes,
and
bacteria.
X140. H&E.
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(c) Epithelium (E) surrounding tonsillar crypts (C) often becomes infiltrated with lymphocytes and other leukocytes and can become difficult to recognize
histologically. Adjacent connective tissue at the top of the photo also contains numerous lymphocytes. X200. H&E.