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The sperm move into the vas deferens, and are eventually expelled through the urethra and out of the urethral orifice through muscular contractions. However, most fish do not possess seminiferous tubules. Instead, the sperm are produced in spherical structures called sperm ampullae. These are seasonal structures, releasing their contents during ...
The vas deferens (pl.: vasa deferentia), ductus deferens ... As in cartilaginous fish, the upper part of the duct forms the epididymis. In many species, the vas ...
In a male, they develop into a system of connected organs between the efferent ducts of the testis and the prostate, namely the epididymis, the vas deferens, and the seminal vesicle. The prostate forms from the urogenital sinus and the efferent ducts form from the mesonephric tubules .
The mesonephros persists and forms the anterior portion of the permanent kidneys in fish and amphibians, but in reptiles, birds, and mammals, it atrophies and for the most part disappears rapidly as the permanent kidney (metanephros) begins to develop [2] during the sixth or seventh week. By the beginning of the fifth month of human development ...
An unusual little skate specimen found off Fishers Island, New York contained a developed testis, vas deferens, and functional clasper on its left side and an adolescent ovary, shell gland, oviduct, and abortive clasper on its right.
The final category are those used for copulation, and deposition of the spermatozoa within the male, these include the penis, urethra, vas deferens, and Cowper's gland. Major secondary sex characteristics include larger, more muscular stature, deepened voice, facial and body hair, broad shoulders, and development of an Adam's apple.
Zangroniz said studies only use a few species of fish and don't represent the more than 30,000 fish species that exist. She added pain is measured in mammals on the grimace scale, often seen in ...
Each worm has reproductive organs such as vas deferens, testis, uterus, vitelline duct, ovary, and vitellaria. [2] They also have flame cells that function as a kidney and remove waste material. A short duct that opens to the outside on the dorsal surface is composed of four canals on each side, two posterior and two anterior, that come ...