List of abbreviations
Vocabulary
of micros-
copic
anatomy
specialist terms
explained in
English +
German

Every attempt was made to provide correct information and labelling, however any liability for eventual errors or incompleteness is rejected!

dieser Seite

Editor:
Dr. med.
H. Jastrow


Conditions
of use
Overview pseudopods (Pseudopodia):
Pages with explanations are linked to the text below the images if available! (Labelling is in German)
neutrophilic granulocyte
with pseudopods (monkey)
B-lymphocytes with
small pseudopods (rat)
thrombocytes also
have pseudopods (rat)
a macrophage moves through connec-
tive tissue using its pseudopods (rat)
human mast cell with
long, thin pseudopods
monocyte in blood with
short pseudopods (rat)
human eosinophilic gra-
nulocyte with pseudopods
similar human eosino-
philic granulocyte
human neutrophil protrudes its
pseudopodfor phagocytosis
human mast cell with
thin pseudopods 1
human mast cell with
thin pseudopods 2

Pseudopods (Terminologia histologica: Pseudopodia) are foot-like elongate thin mobile processes of cells containing cytoplasm and actin filaments. They are no straight protrusions but much more irregularly formed than microvilli. Pseudopods may arise from cytoplasmwithinfew minutes and may also be retracted in similar time. Pseudopods are actively mobile since they contain actin as well as myosin filaments. Due to oriented polymerisation and depolymerisation of actin filaments in the anterior part of a pseudopod a short-time adhaesion of the cell membrane to extracellular structures and contraction of the posterior part of the cytoplasm in case of disattachment in the posterior part of established contact points of the cell to surrounding structures the whole cell is drawn forward by the pseudopod. Hereby myosin 1 binds the cytoskeleton to actin filaments which polymerise anteriorly, i.e. which further grow in this direction. In the intermediate part contractile stressfibres (Terminologia histologica: Fibrae tensionis) consisting of actin filaments and interposed myosin 2 bind to cell-matrix contacts. Contraction of the stress fibres then together with alterations of the cytoskeleton result in a shortening of the cell which anteriorly as mentioned is attached to adjacent matrix via outgrowing pseudopods which altogether results in anterograde movement. Thus pseudopods allow the cell to move actively whereby the velocity of this movement is influenced by  temperature, local concentration of ions and pH value changes as well as by chemotactic substances. Neutrophilic granulocytes can migrate with a speed of 20 to maximal 60 µm in a minute.
Occurrence:
The following cells are able to migrate via pseudopods: free cells in connective tissues: plasma cells, macrophages, eosinophilic granulocytes, mast cells; blood cells: all kinds of granulocytes, lymphocytes, monocytes.
Further, pseudopods are important for phagocytosis of macrophages: pseudopods protrude in direction of a foreign body, e.g. a bactrium, reach it, embrass it and finally by contraction draw it into the cell while the pseudopods fuse with each other before the phagocytosis is finished.

--> microvilli, kinocilia, stereovilli, cell surface structures, cell membrane
--> Electron microscopic atlas Overview
--> Homepage of the workshop


Dr. E. Schiller, Prof. H. Wartenberg and HSD Dr. Klinger kindly provided one image each; other images, page & copyright H. Jastrow.