The pair of seminal vesicles secrete up to 85% of the total volume of seminal fluid. The lumen of each vesicle is highly irregular, giving a honeycomb appearance at low magnification, as shown here. There is a prominent layer of muscle, arranged into inner circular and outer longitudinal. Can you identify it?
During ejaculation, sympathetic stimulation causes contraction of the muscle, to force secretions into the urethra.
Can you identify the epithelium of the seminal vesicles in this magnified image of a seminal vesicle? It is a pseudostratified tall columnar type. It contains secretory cells with lipid droplets in the cytoplasm.
The fluid produced is yellow, viscid and alkaline, and contains fructose, fibrinogen, vitamin C and prostaglandins.