The prostate gland is a conglomerate of 30 to 50 tubular or saclike glands that secrete fluids into the urethra and ejaculatory ducts. The secretory ducts and glands are lined with a moist, folded mucous membrane. The folds permit the tissue to expand while storing fluids. Beneath this layer is connective tissue composed of a thick network of elastic fibres and blood vessels. The tissue that surrounds the secretory ducts and glands is known as interstitial tissue; this contains muscle, elastic fibres, and collagen fibres that give the prostate gland support and firmness. The capsule enclosing the prostate is also of interstitial tissue.
Encyclopædia Britannica
prostate gland (anatomy) -- Encyclopedia Britannica