Connective tissue cells in lamina propria.
680; inset approximately
An example oF cells in loose connective tissue is shown.
are the predominant cells in connective tissue, where they
produce procollagen and other components oF the extracellu-
lar matrix (±ig. 4-7A).
arise From activated B lym-
phocytes and are responsible For producing antibodies.
have small, ovoid nuclei and contain numerous cytoplas-
mic granules. When stained with toluidine blue, these granules
are metachromatically stained and appear purple (±ig. 4-4A).
Mast cells are involved in allergic reactions.
From hematopoietic stem cells and are generally character-
ized by bilobed nuclei and numerous eosinophilic cytoplasmic
granules; they are attracted to sites oF inﬂ ammation by leuko-
cyte chemotactic Factors where they may deFend against a par-
asitic inFection or moderate an allergic reaction.
are phagocytes oF bacteria; each cell has a multilobed nucleus
and some granules in its cytoplasm. ±or more details on
leukocytes, see Chapter 8, “Blood and Hemopoiesis.”
A representation of the cells found in loose
(These cells are not drawn to scale.)
are spindle-shaped cells with ovoid or elliptical
nuclei and irregular cytoplasmic extensions. (2)
have irregular nuclei. The cytoplasm contains many lysosomes;
cell size may vary depending on the level oF phagocytic activ-
contain large lipid droplets, and their nuclei
are pushed to the periphery. They are usually present in aggre-
gate (see ±ig. 4-18). (4)
have centrally located ovoid
nuclei and numerous granules in their cytoplasm. (5)
have eccentric nuclei with peripheral distribution oF het-
erochromatin (clock Face) within the nuclei; a clear Golgi area
is present within the cytoplasm. (6)
nuclei and coarse cytoplasmic granules. (7)
are also Found in connective tissue, and their
numbers may increase in cases oF inﬂ ammation.
is an allergic reaction that may range
From mild to severe and is characterized by increased
, and exudates in the loose connective tissue.
ushing, shortness oF breath, and shock. Anaphylaxis
results From the activation and release oF
inﬂ ammatory mediators
Some drugs can cause IgE-mediated anaphylaxis and
non–IgE-mediated anaphylactoid reactions. Previous
exposure to a suspect antigen is required For the For-
but anaphylactoid reactions can occur
even upon f rst contact in rare cases. Some antibiotics,
such as penicillin, can cause severe allergic reactions.
Immediate administration oF epinephrine, antihista-
mine, and corticosteroids is the f rst option oF emer-
gency treatment, along with endotracheal intubation
to prevent the throat From swelling shut, iF necessary.
Active mast cell
Dilated blood vessel