Detail of a human plasma cell from the pharyngeal tonsil (Tonsilla pharyngea)
(for unlabelled original image click here,
please!)
C = cytoplasm of the
plasma cell (cellular fluid with organells);
Ci = cisterns of the Golgi-Apparatus
(dictyosoms);
cis = cis-side of the Golgi-Apparatus;
Cmv
= Corpusculum multivesiculare (multivesicular
body);
Clv = clathrin coated
vesicle (endocytotic vesicle);
Cri = Crista mitochondrialis (mitochondrial
crista = infolding of the inner mitochondrial membrane);
Ec = euchromatin; Ed
= endocytosis; G =
Golgi-Apparatus;
Hc = heterochromatin;
(free and partly associated to the nuclear
membrane); Hc* = nucleolus
associated heterochromatin;
Ic = Invaginatio cellularis (infolding of the extracellular
Sfa into the cytoplasm);
Mam = Matrix mitochondrialis (mitochondrial
plasma); Mi =
mitochondria (crista-type);
Mm = Membrana mitochondrialis (mitochondrial
membranes);
Mne = Membrana nuclearis externa (outer nuclear
membrane);
Mni = Membrana nuclearis interna (inner nuclear
membrane);
N = nucleus; Nc
= nucleolus (nuclear body);
P = Plasmalemma (cell membrane);
Pa
= Pars amorpha nucleoli (amorphous part of the nucleolus);
Pf = Pars fibrosa nucleoli (fibrous part of the nucleolus);
Pg = Pars granulosa nucleoli (granular part of the nucleolus);
Pnu
= Porus nuclei (nuclear pore);
PR = Polyribosomae (Polyribosomes = grouped ribosomes);
RER = rough endoplasmic reticulum
(in active plasma cells typically dilated
but not here);
SER = smooth endoplasmic reticulum
(in continuity with the RER but free of ribosomes);
Sfa = Substantia fundamentalis amorpha (amorphous
fundamental substance consisting mainly of water);
Spn = Spatium perinucleare (perinuclear
space; space between Mni and Mne);
t = trans-side of the Golgi-Apparatus;
Vs
= Vesicula secreta (secretory vesicle
= Golgivesicle);
# = autophagolysosom
of which wtaer and ions are extracted in the left marginal area; therefore
small vesicles are secreted here.
Plasma cells produce antibodies
(immunglobulins) in their abundant, typically dilated RER. These
immunglubulins are transported via transmenbrane proteins through the cell
membrane into the Sfa. These cells are most important for humoral
defense, i.e. antibody based immune defense. They derive from activated
B-lymphocytes and are usually characterized
by nucleus showing a "spokes of a wheel"
structure, i.e. a large central nucleolus
with euchromatin running like spokes
of a wheel to the nuclear membrane
between the nuclear pores. Plasma
cells are usually seen in connective tissues
and only very rarely free floating in blood.
As free connective tissue cells they
are able to migrate through connective tissues
using their small pseudopods. The
ovoid plasma cells are not surrounded
by a basement menbrane and have diameters of 10 to over 20 µm.
--> plasma cells, free
connective tissue cells, fundamental
substance
--> Electron microscopic atlas Overview
--> Homepage of the workshop
Image, page & copyright H.
Jastrow.
