GS Histology of the male reproductive system

Question 1

Explain the process of spermatogenesis

Answer 1

The testes interstitial tissue produce testosterone, which is under the control of GnRH from the hypothalamus. GnRH stimulates LH and FSH release from the anterior pituitary gland
3 stages of spermatogenesis: Spermatocytogenesis, meiosis, spermiogenesis

1. Spermatocytogenesis
   The process of spermatogenesis begins with mitotic proliferation of the spermatogonia. These cells lie in contact with the BM of the seminiferous tubule. Spermatogonia –> Type A –> Intermediate type I –> Type B. Type B enter prophase of meiosis 1 and become primary spermatocytes (2n).
2. Meiosis
   Meiosis of the Type B spermatocytes resumes to form 4 spermatid gametes (n). These are commonly seen histologically.
3. Spermiogenesis
   The metamorphisis from a simple spermatid into a complex sperm is controlled by Sertoli cells. Sperm which have been produced are structurally complete but are immotile and infertile. They complete their physiological maturation in the epididymis. Sperm are transported through the seminiferous tubules and accessory ducts to the epididymis by the testicular fluid produced by Sertoli cells.

Question 2

Recognise spermatogonia

Answer 2

Found close to BM

Spherical

Question 3

recognise spermatocytes

Answer 3

As prophase is elongated, easy to identify
Numerous in sections of the seminiferous tubules
Large nuclie
Thick, prominent chromosomes

Question 4

recognise spermatids

Answer 4

Numerous but difficult to identify

Close to lumen

Question 5

Distinguish between the different regions of the accessory ducts and understand their functions

Answer 5

1. Rete testis
   A system of irregular channels located in the connective tissue of the mediastinum testis. Testicular fluid secreted by the Sertoli cells washes sperm from the seminiferous tubules into the rete testes.
   Function: Collecting system linking the seminiferous tubules with the efferent tubules
2. Efferent ductules
   Emerge from the rete testis and fuse to form a single highly coiled duct inside the epididymis.
   Lumen is scalloped due to tall ciliated cells (1) alternating with shorter non-ciliated cells (2). Ciliary current draws testicular fluid produced by Sertoli cells of the seminiferous tubules towards the epididymis.
3. Epididymis
   Highly convoluted single tubule that starts in superior pole and continues inferiorly as the vas deferens.
4. Vas deferens
   Lies within spermatic cord along with testicular artery, the plexus of veins, smooth muscle fibres of the cremaster muscle and lymphatics.
   Joins seminal vesicle to for ejaculatory ducts which enter the prostate.

Question 6

list the accessory glands and explain the function of their secretions

Answer 6

1. Seminal vesicle
2. Prostate gland
3. Bulbo-urethral glands (Cowper’s glands)

Function:

• secrete fluids which provide physical and nutrient support for spermatozoa which are ejaculated at orgasm.
• The bulbo-urethral glands together with the paraurethral glands of the penis, lubricate the penile urethra