Question

What is the male reproductive system of histology
Give full information?

Answer 1

Testis Histology

Convoluted Seminiferous Tubules

tubules are enclosed by a thick basal lamina and surrounded by 3-4 layers of smooth muscle cells (or myoid cells).tubules are lined with seminiferous epithelium consisting of two cell types: spermatogenic cells and Sertoli cells.

Spermatogonia

first cells of spermatogenesis.originate in week 4 of fetal development in the endodermal walls of the yolk sac and migrate to the primordium of the testis, where they differentiate into spermatogonia.Spermatogonia remain dormant until puberty. They are always in contact with the basal lamina of the tubule.Two types of spermatogonia can be distinguished in the human seminiferous epithelium:


** Type A spermatogonia have a rounded nucleus with very fine chromatin grains and one or two nucleoli. They are stem cells which divide to form new generations of both type A and type B spermatogonia. 
** Type B spermatogonia have rounded nuclei with chromatin granules of variable size, which often attach to the nuclear membrane, and one nucleolus. Although type B spermatogonia may divide repeatedly, they do not function as stem cells and their final mitosis always results in the formation of primary spermatocytes.

Primary spermatocytes

lie in the cell layer luminal to the spermatogonia.appear larger than spermatogonia.immediately enter the prophase of the first meiotic division, which is prolonged (about 22 days).large number of primary spermatocytes is always visible in cross-sections through seminiferous tubules.cell divisions, from the formation of primary spermatocytes and onwards, to the production of the spermatocytes, are incomplete.cells remain connected by bridges of cytoplasm.completion of the first meiotic division results in the formation of secondary spermatocytes

Secondary spermatocytes

smaller than primary spermatocytes.rapidly enter and complete the second meiotic division (seldom seen in histological preparations).division results in the

Answer 2

!!

The main functions of the male reproductive system, are to produce spermatozoa, androgens (sex hormones - principally testosterone) and to facilitate fertilisation, by introducing spermatozoa into the femal genital tract (copulation). The male reproductive system includes the testis, genital ducts, accessory sex glands and penis.

Δ Testis

• The pair of testes produces spermatozoa and androgens. Several accessory glands produce the fluid constituents of semen. Long ducts store the sperm and transport them to the penis.
• The male reproductive system consists of paired testes and genital ducts, accessory sex glands and the penis. The testes and ducts are shown in this diagram.

Δ Epidymis

• The looped seminiferous tubules in the testes are connected to the genital duct system which transports the spermatozoa and fluid component of the semen to the outside.
• This duct system is made up of the tubuli recti (short straight tubules connected to the seminiferous tubules), the rete testis - which is found in the mediastinum testis. The rete testis empties into the ductuli efferentes that lead into the ductus epididymus.
• The ductus epididymus empties into the vas deferens, which empties into the ejaculatory duct, which empties into the urethra and passes to the outside.

Δ Penis

• A pair of corpora cavernosa, and the corpus spongiosum that surrounds the urethra, ending in the glans penis.
• Penile skin moves freely over the underlying tissues due to the loose hypodermis - can you identify this? Unless circumcised, it extends over the glans as the prepuce (foreskin) a retractable protective fold of skin.
• The coprora contain irregular vascular spaces, lined by endothelium. Errection of the penis follows parasympathetic stimulation. Smooth muscle in the thick walled distributing arteries relaxes, and the vascular spaces fill with blood. As the corpora distend, they press against the inextensible tunica albuginea, compressing the veins, so blood is less able to drain away. The corpus spongiosum has a more extensible tunica albuginea, and so becomes less turgid, avoiding compression of the penile urethra.

Δ Seminal vesicle

• 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.
• There is a prominent layer of muscle, arranged into inner circular and outer longitudinal.
• During ejaculation, sympathetic stimulation causes contraction of the muscle, to force secretions into the urethra.

Δ Prostate Gland

• This section is taken from the peripheral zone of the prostate.
• The glands are branched, and the epithelium is folded. The secretory product , which makes up part of the seminal fluid, is thin and milky, rich in citric acid, and hydrolytic enzymes, including fibrinolysin, which liquefies coagulated semen after deposition in the female genital tract. The stroma lying between the secretory units is fibromuscular, and contracts to expel the secretions, during ejaculation.

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