Male reproductive System Part 1 Flashcards
Function of Testes
- Produce sperms and the male hormone – testosterone.
- Transport of sperms by a series of ducts - epididymis, vas deferens and ejaculatory ducts into the prostatic part of the urethra.
Presenting parts of testes:
Upper pole
* Directed forwards and laterally
* Overlapped by head of the epididymis
* Connected to the head by efferent ductules
* Near the upper pole it gives attachment to a sessile fibro-fatty body – appendix of testis: remnant of paramesonephric duct [Mullerian duct]
Lower pole
* Directed backwards and medially
* It is attached to the scrotal wall by scrotal ligament – a remnant of gubernaculum testis
Anterior border - rounded and convex. Covered by tunica vaginalis
Posterior border – broad and flat, not covered by tunica vaginalis.
* Gives attachment to spermatic cord in the upper part
* Related to epididymis postero-laterally and vas deferens postero-medially
Medial surface: smooth and convex
Lateral surface: smooth and convex, overlapped posteriorly by the epididymis, which is separated from the
Coverings of the testis: Three coverings which collectively form its capsule.
- Tunica vaginalis
Derived from processus vaginalis.
* Both the testis and epididymis are covered by the two layers of tunica vaginalis except the posterior aspect of the testis.
* Consists of 2 layers – parietal layer and visceral layer.
* Parietal layer lines the innermost layer of the scrotal wall.
* Visceral layer covers the front and sides (medial and lateral surfaces) of the testis and epididymis.
* Between the two layers is a potential space containing a thin film of fluid - Tunica albuginea
Thick layer of fibrous tissue made up of dense collagen fibres.
* It projects from the posterior margin of the testis into the interior of the testis as a septum called mediastinum testis.
* This septum is traversed by blood vessels, lymph vessels and an intercommunicating network of channels called rete testis.
* A no. of fibrous septae called septulae testis extend forwards and laterally – divide the testis into 200 to 300 compartments called lobules of the testis.
* Each lobule contains 2 to 3 convoluted seminiferous tubules – where sperms are produced.
* Near the mediastinum the convoluted tubules join to form straight seminiferous tubules.
* These enter the mediastinum testis to form rete testis - Tunic vasculosa
Arterial supply of Testes:
branch of abdominal aorta, arises at the level of L2.
* Entersthedeepinguinalring.
* Runswithinthespermaticcord
* At the posterior border of the testis it divides into branches.
* Branches enter the mediastinum testis and then form tunica vasculosa.
* Testis is also supplied by (a) artery to the vas deferens – branch of superior vesical or inferior vesical arteries (b) cremasteric artery – branch of inferior epigastric artery.
Venous drainage of Testes:
- Many testicular veins emerge from the testis – form a venous network called pampiniform plexus which forms the bulk of the spermatic cord.
- At the superficial inguinal ring 4 veins are formed from the plexus. At the deep inguinal ring the four veins join to form 2 veins. Further up the 2 veins unite to form one vein.
- On the right side testicular vein drains into the IVC.
On the left side the vein drains into the left renal vein.
What is Varicocele?
- Is a condition in which pampiniform plexus of veins become tortuous and dilated.
- On palpation, the spermatic cord feels like a “bag of worms”.
- Common on the left side.
Anatomical factors responsible for the more common
1. Left testicular vein longer than the right.
2. Left vein opens into the left renal vein at right angle (right vein opens into IVC at an acute angle).
3. Left testicular vein passes posterior to descending colon. Therefore when there is constipation it can compress the left testicular vein.
4. Tumors of the left kidney may grow along the left renal vein and may block the opening of left testicular vein. - The rise in scrotal temperature due to varicocele may sometime interfere with spermatogenesis.
Lymphatic drainage of Testes:
Preaortic and para- aortic (lateral aortic) lymph nodes on the posterior abdominal wall (from both testis and epididymis)
* At times enlargement of these lymph nodes may be the only sign of testicular cancer.
Nerve supply of Testes:
Sympathetic efferent fibres through coeliac and testicular plexuses from T10 and to T11 segments of the spinal cord
* Afferent fibres travel in the same plexuses to lesser and least splanchnic nerves which carry them to the same segments of the spinal cord.
* The testicular pain is referred to the umbilical region due to same segmental innervations (T10)
Importance of Testicular thermoregulation:
Factors responsible for maintaining the temperature of scrotum:
* Scrotal sweat glands are numerous and subcutaneous fat is absent in the scrotal skin.
* Contraction of dartos muscle - in cold condition reduces the surface area of scrotal skin.
* Countercurrent heat exchange mechanism is said to exist between the testicular artery and pampiniform plexus of veins in the spermatic cord. The artery is entwined in venous plexus so that heat is absorbed from the artery into the veins. In this way pre-cooled blood reaches the testis.
Microanatomy of Testis:
- Supporting (Sertoli) cells:
* They provide mechanical support and protection for developing germ cells.
* They also participate in the nutrition and maturation of spermatozoa. - Spermatogenic cells:
The arrangement of spermetogenic cells from the basement membrane towards the lumen is as follows.
* Spermetogonia cells
* Primary spermatocytes
* Secondary spermatocytes
* Spermatids
Torsion of the testis or spermatic cord:
It is twisting of the spermatic cord or rotation of the testis around the spermatic cord within the scrotum.
What is Hydrocele:
- Presenceofexcessoffluidinthepersistentprocessesvaginalis
- Congenital anomaly, may be associated with indirect inguinal
hernia. - Accumulation results from the secretion of abnormal amount of serous fluid from the visceral layer of tunica vaginalis.
- Size of hydrocele depends on how much of processes vaginalis persists.
- Hydrocele of testis - confined to scrotum, distends the tunica vaginalis.
- Hydroceleofthecord-confinedtospermaticcord
- Congenital hydrocele of the cord and testis may communicate
with the peritoneal cavity.
Detection of hydrocele by transillumination – bright light applied to
the side of scrotal enlargement in a darkened room. Transmission of
light as a red glow indicates excess of serous fluid in the scrotum.
What is HEMATOCELE:
- Collection of blood in the tunica vaginalis due to rupture of branches of testicular artery or trauma to testis.
- Blooddoesnottransilluminate.
- Therefore transillumination can differentiate hydrocele
from hematocele.
CARCINOMA of testis is called:
seminoma.
Arises from germ cells.
* Subsequent spread may be to mediastinal and supraclavicular nodes.
Cancer of scrotum – spreads to superficial inguinal nodes.
* Metastasis of testicular cancer may also occurs by hematogenous spread to the – lungs, liver, brain and bone.
WHat is Epididymal cyst ?
collection of fluid anywhere in the epididymis. Incidentally found and it is asympatamatic. Treated surgically
WHat is Orchiectomy:
surgical removal of testes to treat prostate cancer
WHat is Ectopy:
- Testis has not followed normal path of descent.
- Most common site is superficial inguinal ring.
What is Cryptorchidism:
- Arrest of testicular descent.
- Cryptorchidism is common,
especially unilaterally. - At birth, it affects 3.4% boys (30% in prematurity). Half of these descend by the end of first month of life.
What is Hypogonadism:
- Small testes with lack of development of secondary sexual characteristics, lack of libido and potency.
- Characteristically, patients are tall with long extremities.
- Also associated with Klinefelter’s syndrome.
- Also associated with physiological problems
and low intelligence.
What is Spermatocele [retention cyst]:
- Painless cystic mass found just above or
posterior to the testis. - Contain milky fluid and are generally
asymptomatic.
What are Vestigial remnants of embryonic genital ducts :
- Appendix of the testis – a vesicular remnant of the cranial end of the paramesonephric duct [Mullerain duct] (In the female the two paramesonephric ducts form uterine tubes, uterus and upper part of vagina)
- Appendix of the epididymis – remnant of the cranial end of mesonephric duct [Wolffian duct]
Course of the vas deferens in the pelvis:
- As it runs backwards and somewhat downwards along the lateral wall, it crosses medial to:
1) obliterated umbilical artery and superior vesical artery
2) obturator nerve and vessels
3) inferior vesical artery - Then it crosses the ureter from above and in front from lateral to medial side.
- Runs downwards and medially behind the base of the urinary bladder.
- Here it lies medial to the seminal vesicle and in front of the rectum.
- The part lying behind the base of the bladder is dilated and is called ampulla.
- The terminal part joins the duct of the seminal vesicle to form the ejaculatory duct.
Arterial supply of the ductus deferens:
- Artery to the ductus deferens – branch of superior vesical (sometimes) or inferior vesical artery. This artery terminates by anastomosing with the testicular artery near the posterior border of the testis.
Venous drainage of ductus deferens:
- From most of the ductus into the testicular vein including the distal part of pampiniform plexus.
- Its terminal part drains into vesical or prostatic venous plexus.
Lymphatic drainage of ductus deferens:
into the external iliac lymph nodes
Development of ductus deferens:
from mesonephric duct
Microanatomy of Ductus deferens:
Mucous coat
* It has a narrow fan-shaped lumen lined by ciliated columnar epithelium or pseudo-stratified epithelium.
* The lamina propria contains an extensive elastic network, which is responsible for the folds of epithelium.
Muscle coat:
*It has a thick muscle coat made up of smooth muscle fibers , which are arranged in 3 layers
* They are inner and outer longitudinal and middle circular layers
Adventitia:
* It is made up of a thin layer of connective tissue and blood vessels and nerves
