Sarcoplasm

Part of speech: noun

Definitions

1. The cytoplasm that fills the interior of a muscle cell, surrounding the myofibrils and containing mitochondria and other organelles
2. The gel-like substance within a muscle fiber that lies between the contractile filaments and contains the cell's metabolic machinery
3. The protoplasmic material of a muscle cell that occupies the space around the contractile elements and supports the fiber's metabolic functions

Etymology: Sarcoplasm is a compound built from two Greek elements. "Sarx" meant "flesh," and "plasma" meant "something formed or molded," which in English came to mean the fluid part of a living cell. Put together, the term names the cytoplasm of a muscle cell, the substance that surrounds its fibres. The "sarco-" part is the same Greek root that appears in "sarcophagus," literally "flesh-eater," a stone coffin once thought to consume a corpse's flesh. Its use in biology is a more recent scientific coinage built from classical roots rather than a term the ancient Greeks themselves used for muscle cells. Because the word is a technical formation from two Greek parts, it carries no folk story behind it; its meaning is simply the flesh-substance of muscle. Its specific sense, though, depends on the modern understanding of muscle as a tissue made of fibres, each one a single elongated cell.

Synonyms: sarcoplast, cytoplasm