from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Any of the cells of the gonads in male organisms that are the progenitors of spermatocytes.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. Any of the undifferentiated cells in the male gonads that become spermatocytes; a spermatoblast
from the GNU version of the Collaborative International Dictionary of English
- n. A primitive seminal cell, occuring in masses in the seminal tubules. It divides into a mass (spermosphere) of small cells (spermoblast), which in turn give rise to spermatozoids.
from The Century Dictionary and Cyclopedia
- n. In botany, same as pycnidium, 1.
- n. A primitive or formative seminal cell, forming a kind of sperm-morula, or spermosphere composed of spermatoblasts or spermatocytes, which in turn give rise to spermatozooids.
When a spermatogonium was observed to change to a primary spermatocyte-still diploid-it would be segregated and at the instant it divided into two secondary spermatocytes-haploids, one with an X chromosome and one with a Y chromosome-they would be again segregated and each would be encouraged to develop into spermatozoa. \par
Difference Between spermatogenesis and Spermiogenesis • Spermatogenesis is the complete process of formation of spermatozoon from a spermatogonium.
The symbols used are: spermatogonium (white pentagon); primary spermatocytes (white stars); round spermatids (white asterisk); elongated spermatids with high polarization, indicating the residual body or axonemal region (black asterisk) and the heads (white arrowheads).