6.0.0 MALE ORGANS: INTRODUCTION
The masculine tract is divided in the following compartments:
6.1 - images: Testis (production of sperm). Under the influence of the Y-chromosome in seven-weeks old testes the primary sex cords have become seminiferous cords. These develop into seminiferous tubules without a lumen and of two types of cells: spermatogonia and sustentacular cells. The adult testis encapsulated by a dense tunica albuginea is found covered by a serous tunic (=epiorchium) within the scrotum (=a cutaneous fibromuscular sac). The tunica albuginea is absent at the hilum creating a passage for tubules, vessels and nerves. From the hilum radially arranged connective tissue septa (septula testis) divide the testis in about 200-250 pyramid-like lobuli testis. Each pyramid contains 2-5 tubuli seminiferi contorti (30-70 cm long) in a stroma with clusters of Leydig cells. The tortuous tubules run towards the hilum, become straight tubules that form the anastomosing network of the rete testis. Subsequently they connect with the efferent tubules of the epidydimis. Sperm and testicular fluid production occurs in the germinal epithelium of the seminiferous tubules. Spermatogenesis and spermiogenesis are present in the enveloping processes of the Sertoli cells and are dependent on the testosterone concentrations produced by interstitial cells (Leydig). Spermatozoa that are released in the lumena of seminifous tubules are non-motile, they moved toward the tubuli recti by the flow of testicular fluid and some peristalsis of the seminiferous tubules. The smooth muscles and ciliated epithelium of the efferent tubules move the spermatozoa into the caput of the epididymis. Testicular fluid is absorbed in the efferent tubules and in the proximal part of the epididymis.
See: 6.1 POJA-L2662 et al; 6.1 POJA-L2677 et al; 6.1 POJA-L2678 et al.; 6.1 POJA-L2954 et al; 6.1 POJA-L4238 et al; 6.1 POJA-L4240 et al.
6.2 - images: Epididymis (store) / Deferent duct (transport). The 5 cm long epidydimis is divided in a caput, corpus and cauda. About 20 cm long efferent tubules (10-20) are predominantly found in the caput, the caudal part contains the 4-5 m long tortuous epidydimal duct. The latter is provided with a circular oriented smooth muscle wall that is reinforced by a longitudinal oriented smooth muscle cell at the caudal end. The various segments of the epididymis control/regulate/activate the fertilization capacity of the spermatozoa (capacitation). Sperm is stored in the caudal epididymis with its thick muscular wall. There is a gradual transition towards the strongly developed muscular deferent duct. Muscular contraction of the cauda in coordination with the wall of the deferent duct empty stored sperm into the prostatic urethra. The deferent duct runs towards the area of the glands (seminal vesicles and prostate), and inside the prostate it loses the muscular wall and is now known as ejaculatory duct.
See: 6.2 POJA-L2709 et al; 6.2 POJA-L2717 et al; 6.2 POJA-L2744 et al; 6.2 POJA-L4240 et al.
6.3 - images: Seminal vesicle (glands). The seminal vesicle is a tortuous duct of 15 cm long with secretory cells. It develops as an outgrowth of the deferent duct behind the prostate. It has a muscular wall and an adventitia with additional connective tissue functions as a capsule. The alkaline secretion serves as a liquid vehicle for spermatozoa, is clear brown-yellowish and contains a.o. fructose, globulins, drains via the ejaculatory duct.
See: 6.3 POJA-L2734 et al; 6.3 POJA-L4242+La0202; 6.3 POJA-L4243 et al.
6.4 - images: Unpaired Prostate (gland). The unpaired prostate is a ca. 4 cm large gland consisting of 30-50 branched small tubulo-alveolar glands embedded in stroma with bundles of smooth muscle cells. The glands drain via 15-30 small prostatic ductuli close to the outlet of the ejaculatory duct (so-called colliculus seminalis) in the urethra.
Upon stimulation of androgens the gland cells produce a weakly acid secretion containing a.o. acid phosphatase, protease, citric acid, fibrolysine. The secretion is milky in appearance with a characteristic odour and stimulates spermatozoa motility as well. With ageing prostatic calculi or corpora amylacea are regularly present as concentric calcifications.
See: 6.4 POJA-L2723 et al; 6.4 POJA-L4244 et al; 6.4 POJA-La0205 et al.
6.5 -images: Unpaired urethra (drainage). The penis is composed of two cavernous bodies (=corpora cavernosa) and one corpus spongiosum encompassing the urethra. The bodies are wrapped by dense connective tissue (=tunica albuginea) and a thin loosely skin. The cavernous bodies are composed of networks of fibromuscular trabecles creating labyrinthine spaces lined with endothelial cells.
Nerve fibers, ganglion cells, elastic and collagen fibers, and small blood vessels (e.g. helicinae arteries) are present in these trabecles. In the functional circuit blood in the spaces (or sinuses) is derived directly from the helicinae arteries and due to enlarging of the cavernous tissues by loss of tonus in the smooth muscle cells of the trabecles and the deep arterial wall. The result is blocking of the draining via superficial venous marginal caverns (turgid state or intumescence). Detumescence (flaccid state) indicates unblocking of the draining via the caverns by increase in tonus of smooth muscles in the deep arterial media and in the lacunae. The inflow of blood is blocked and blood in the lacunae is slowly excluded.
See: 6.5 POJA-L2749 et al; 6.5 POJA-L4248B et al; 6.5 POJA-L4249 et al; 6.5 POJA-L4251+4252B.
6.6 - images: Pathology samples
Infertility: See: 6.6 POJA-L2705 et al; 6.6 POJA-L3340 et al.
Seminoma: See: 6.6 POJA-L3848+3849.
COPYRIGHTS
All rights reserves worldwide for the POJA collection are hold by L.G. Poels and P.H.K. Jap and Radboud University Medical Center (Radboud UMC Nijmegen). No one may modify, copy, distribute, transmit, display, or publish any materials contained in the POJA collection without prior written permission of the authors Poels and Jap or the UMC St Radboud. Any commercial use of the POJA collection is forbidden. POJA images are partly deposited in the Health Education Assets Library (HEAL database) as well as in the MedEdPortal/AAMC database).
All rights reserves worldwide for the POJA collection are hold by L.G. Poels and P.H.K. Jap and Radboud University Medical Center (Radboud UMC Nijmegen). No one may modify, copy, distribute, transmit, display, or publish any materials contained in the POJA collection without prior written permission of the authors Poels and Jap or the UMC St Radboud. Any commercial use of the POJA collection is forbidden. POJA images are partly deposited in the Health Education Assets Library (HEAL database) as well as in the MedEdPortal/AAMC database).