Male reproductive system LECTURE FOR MEDICAL STUDENTS DEPARTMENT OF HISTOLOGY, CYTOLOGY AND EMBRYOLOGY KhNMU 2012

The internal male genitalia: the testes the testes the epididymis, the epididymis, the vas deferens the vas deferens the accessory sex glands - the seminal vesicles, the accessory sex glands - the seminal vesicles, the prostrate and the prostrate and the bulbourethral glands the bulbourethral glands

Functions: Reproductive --- produce the male gametes or spermatozoa, and Reproductive --- produce the male gametes or spermatozoa, and Endocrine --- produce male sexual hormone (testosterone) Endocrine --- produce male sexual hormone (testosterone)

Testes

The structure of Testes Connective tissue a thick capsule - the tunica albuginea a thick capsule - the tunica albuginea the mediastinum testis, projects into the testis and give septae the mediastinum testis, projects into the testis and give septae Septae – divide testes on lobules Septae – divide testes on lobules

Each Lobule consist of: Connective tissue -- Interstitium -- with Leidig cell Connective tissue -- Interstitium -- with Leidig cell Seminiferous tubules (1-4 per lobule) Seminiferous tubules (1-4 per lobule)

Leydig cells (15-20 µm) Leydig cells (15-20 µm) synthesise and secrete testosterone. synthesise and secrete testosterone.

The Convoluted Seminiferous Tubules Consists of two types of cells: spermatogenic cells spermatogenic cells Sertoli cells. Sertoli cells.

The Convoluted Seminiferous Tubules Consists of two general types of cells: spermatogenic cells spermatogenic cells Sertoli cells. Sertoli cells.

Spermatogenic cells Spermatogonia - Type A spermatogonia - Type B spermatogonia Spermatogonia - Type A spermatogonia - Type B spermatogonia Primary spermatocytes Primary spermatocytes Secondary spermatocytes Secondary spermatocytes Spermatids Spermatids Spermatozoa Spermatozoa

Spermatogenesis Type A spermatogonia are stem cells Type A spermatogonia are stem cells which divide to form new generations of spermatogonia. which divide to form new generations of spermatogonia.

Spermatogenesis Type B spermatogonia --- Type B spermatogonia --- their final mitosis always results in the formation of Primary spermatocytes

Primary spermatocytes appear larger than spermatogonia. Primary spermatocytes appear larger than spermatogonia. They immediately enter the prophase of the first meiotic division, which is extremely prolonged (about 22 days!). They immediately enter the prophase of the first meiotic division, which is extremely prolonged (about 22 days!).

The completion of the first meiotic division results in the formation of Secondary spermatocytes The completion of the first meiotic division results in the formation of Secondary spermatocytes

Secondary spermatocytes, are smaller than primary spermatocytes. Secondary spermatocytes, are smaller than primary spermatocytes. They rapidly enter and complete the second meiotic division. They rapidly enter and complete the second meiotic division.

Their division results in the formation of Spermatids, which lie in the luminal part of the seminiferous epithelium. Their division results in the formation of Spermatids, which lie in the luminal part of the seminiferous epithelium.

The terminal phase of spermatogenesis is called spermiogenesis The terminal phase of spermatogenesis is called spermiogenesis and consists of the differentiation of the newly formed spermatids into Spermatozoa and consists of the differentiation of the newly formed spermatids into Spermatozoa

Spermatogenesis Cell divisions are incomplete. The cells remain connected by bridges of cytoplasm. Cell divisions are incomplete. The cells remain connected by bridges of cytoplasm.

Structure of spermatozoa

Sertoli cells - provide mechanical support for the spermatogenic cells. - provide mechanical support for the spermatogenic cells. -- provide blood- testis barrier. -- provide blood- testis barrier. --- have a nutritive function. --- have a nutritive function.

Eccurrent ducts MRS consists of DUCTS MRS consists of DUCTS

epididymis - anatomy The head of the epididymis receives the efferent ductules. The head of the epididymis receives the efferent ductules. The tail of the epididymis leads into the vas deferens. The tail of the epididymis leads into the vas deferens. vas deferens vas deferens

epididymis The epididymis is essentially a long, highly coiled tube. The epididymis is essentially a long, highly coiled tube.

efferent ductules

Epididymis ductus epididymidis It is lined by a very tall pseudostratified columnar epithelium: principal cells, (have long stereocilia) principal cells, (have long stereocilia) basal cells basal cells

ductus epididymis The epididymal duct is extremely long (4 to 5 meters) but is highly convoluted The epididymal duct is extremely long (4 to 5 meters) but is highly convoluted It is surrounded by smooth muscle and embedded within a loose, vascular stroma. It is surrounded by smooth muscle and embedded within a loose, vascular stroma.

Vas deferens mucosa mucosa muscularis muscularis adventitia adventitia

the accessory sex glands - the seminal vesicles, - the seminal vesicles, the prostrate and the prostrate and the bulbourethral glands the bulbourethral glands

Male Accessory Reproductive Glands Seminal Vesicles

Seminal Vesicles functions: the formation of the sperm coagulum, the formation of the sperm coagulum, the regulation of sperm motility and the regulation of sperm motility and

Male Accessory Reproductive Glands

Prostate is the largest accessory sex gland in men (about 2 x 3 x 4 cm). is the largest accessory sex gland in men (about 2 x 3 x 4 cm). The secretion contains citric acid, the enzyme fibrinolysin, acid phosphatase, a number of other enzymes and lipids. The secretion contains citric acid, the enzyme fibrinolysin, acid phosphatase, a number of other enzymes and lipids.

Male Accessory Reproductive Glands It contains tubuloalveolar glands, which empty into independent excretory ducts. These ducts open into the urethra. It contains tubuloalveolar glands, which empty into independent excretory ducts. These ducts open into the urethra.

the peripheral zone contains large, so- called main glands, whose ducts run posteriorly to open into the urethra. the peripheral zone contains large, so- called main glands, whose ducts run posteriorly to open into the urethra. the internal zone consists of the so- called submucosal glands, whereas the internal zone consists of the so- called submucosal glands, whereas the innermost zone contains mucosal glands. the innermost zone contains mucosal glands.

Male Accessory Reproductive Glands The glands are embedded into a fibromuscular stroma, which consists of smooth muscle and connective tissue rich in collagenous and elastic fibres. The glands are embedded into a fibromuscular stroma, which consists of smooth muscle and connective tissue rich in collagenous and elastic fibres.

Male Accessory Reproductive Glands The epithelium is cuboidal or columnar. The epithelium is cuboidal or columnar. Prostate

Prostate A characteristic feature of the prostate is the appearance of corpora amylacea in the secretory alveoli.

Prostate They are rounded eosinophilic bodies. Their average diameter is about 0.25 mm (up to 2 mm). They appear already in the seventh month of foetal development. Their number increases with age - in particular past 50. They may undergo calcification. Corpora amylacea may appear in semen.

Male Accessory Reproductive Glands Prostate