endoplasmic reticulum

reticulum /re·tic·u·lum/ (rĕ-tik´u-lum) pl. retic´ula   [L.]

1. a small network, especially a protoplasmic network in cells.

2. reticular tissue.

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endoplasmic reticulum  an ultramicroscopic organelle of nearly all higher plant and animal cells, consisting of a system of membrane-bound cavities in the cytoplasm; occurring in two types, rough-surfaced (granular r.), bearing large numbers of ribosomes on its outer surface, and smooth-surfaced (agranular r.) .

sarcoplasmic reticulum  a form of agranular reticulum in the sarcoplasm of striated muscle, comprising a system of smooth-surfaced tubules surrounding each myofibril.

stellate reticulum  the soft, middle part of the enamel organ of a developing tooth.

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endoplasmic reticulum

n. Abbr. ER

The membrane network in cytoplasm that is composed of tubules or cisternae. Some membranes carry ribosomes on their surfaces while others are smooth.

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endoplasmic reticulum

[-plaz′mik]

Etymology: Gk, endon + plassein, to mold

an extensive network of membrane-enclosed tubules in the cytoplasm of cells. The structure functions in the synthesis of proteins and lipids and in the transport of these metabolites within the cell.

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reticulum [rĕ-tik´u-lum] (L.)

1. a small network, especially a protoplasmic network in cells.

2. reticular tissue.

agranular reticulum smooth-surfaced endoplasmic reticulum.

endoplasmic reticulum an ultramicroscopic organelle of nearly all higher plant and animal cells, consisting of a system of membrane-bound cavities in the cytoplasm, occurring in two types: granular or rough-surfaced, bearing large numbers of ribosomes on its outer surface, and agranular or smooth-surfaced.

granular reticulum rough-surfaced endoplasmic reticulum.

sarcoplasmic reticulum a form of agranular reticulum in the sarcoplasm of striated muscle, comprising a system of smooth-surfaced tubules surrounding each myofibril.

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endoplasmic reticulum (ER),

n an extensive network of membrane-enclosed tubules in the cytoplasm of a cell.