FIGURE 22.28 • Photomicrograph of human prostate gland. a. This Mallory-azan–stained specimen shows the tubuloalveolar glands (Gl) and the fibromuscular tissue that forms the septa between glandular tissue. Within the lumina, various-sized prostatic concretions can be seen. The stain used for this specimen readily distinguishes the smooth muscle component (stained red) from the dense connective tissue component (stained blue) of the stroma. 60. b. This higher magnification shows an area where the glandular epithelium is pseudostratified. The round nuclei adjacent to the connective tissue (arrowheads) belong to the basal cells. Those nuclei that are more elongate and further removed from the base of the epithelium belong to the secretory cells. Note the terminal bars (arrows) that are evident at the apical region of these cells. The red-stained sites within the dense connective tissue represent smooth muscle cells. 635.
on the functional state of the gland, is under the control of testosterone.
The clear, mucus-like glandular secretion contains considerable amounts of galactose and galactosamine, galacturonic acid, sialic acid, and methylpentose. Sexual stimulation causes release of this secretion, which constitutes the major portion of the preseminal fuid and probably serves to lubricate the penile urethra.
Semen contains fluids and sperm from the testis and secretory products from the epididymis, ductus deferens, prostate, seminal vesicles, and bulbourethral glands. It is alkaline and may help to neutralize the acid environment of the urethra and the vagina. Semen also contains prostaglandins that may influence sperm transit in both the male and female reproductive ducts and that may have a role in implantation of a fertilized ovum.
The average ejaculate of semen has a volume of about 3 mL and normally contains up to 100 million sperm per milliliter. It is estimated that 20% of the sperm in any ejaculate are morphologically abnormal and nearly 25% are immotile.
Erection of the penis involves the filling of the vascular spaces of the corpora cavernosa and corpus spongiosum.
The penis consists principally of two dorsal masses of erectile tissue, the corpora cavernosa, and a ventral mass of erectile
FIGURE 22.29 • Photomicrograph of human bulbourethral gland. This photomicrograph shows an H&E–stained section of the compound tubuloalveolar bulbourethral gland. The epithelium consists of columnar mucus-secreting cells. The nuclei are displaced to the base of the cells by the accumulated secretory material that they contain. The cytoplasm has an appearance similar to typical mucus-secreting cells. Note several ducts (D) lined by a simple columnar epithelium. The ducts will merge to form a single excretory duct. In some sites the ducts contain mucus-secreting cells (arrows). 40.
tissue, the corpus spongiosum, in which the spongy part of the urethra is embedded. A dense, fibroelastic layer, the tunica albuginea, binds the three together and forms a capsule around each (Fig. 22.30). The corpora cavernosa contain numerous wide, irregularly shaped vascular spaces lined with vascular endothelium. These spaces are surrounded by a thin layer of smooth muscle that forms trabeculae within the tunica albuginea interconnecting and criss-crossing the corpus cavernosum. Irregular smooth muscle bundles are observed frequently as “subendothelial cushions” surrounding irregular vascular spaces (Fig. 22.31). The interstitial connective tissue contains many nerve endings and lymphatic vessels. The vascular spaces increase in size and rigidity by filling with