Male Reproductive Organs Flashcards
Describe how processus vaginalis forms.
- During embryonic development, the testes migrate from the posterior abdominal wall through the anterior abdominal wall and into the scrotum
- Each testis takes with it the ductus deferens, the testicular vessels and a loop of parietal peritoneum known as the processus vaginalis that after birth should lie as a closed potential space around the testes known as the tunica vaginalis
Describe the process of testes descent.
The gubernaculum (“fetal, retroperitoneal, mesenchymal cord that extends between the caudal pole of the fetal testis and the scrotum”) shrinks to draw the testes down the posterior abdominal wall (outside the peritoneum) to the inguinal canal and then through the inguinal canal during the 8th and 9th months so that the testes are in the scrotum by birth
Identify possible abnormalities arising from defect in the tunica vaginalis.
If the proximal part of the tunica vaginalis stays open, it can lead to an indirect inguinal hernia or a hydrocele
How does the inguinal canal arise ?
Inguinal canal (“tunnel”) created by the descent of the testes “pushing” through the 3 layers of muscle
Define inguinal canal.
The inguinal canal is an oblique passage, about 4 to 6cm long (variable!), through the anterior abdominal wall connecting the abdominal cavity to the scrotum in males or the labia majora in females.
What are the contents of the inguinal canal ?
Contains:
- Spermatic cord (biological males only)
- Round ligament (biological females only)
- Ilioinguinal nerve
- Genital branch of the genitofemoral nerve
Identify the main function of the scrotum.
The scrotum suspends the testes outside the body allowing for optimal thermoregulation with temperatures lower that the body core for normal spermatogenesis
Describe the skin of the scrotum.
The skin of the scrotum is
− rugose
− has no fat
− contains the dartos muscle (smooth muscle)
State the innervation of the dartos muscle (present in the scrotum).
Supplied by sympathetic fibres in the genital branches of the genitofemoral nerves
Describe the main structural features of the scrotum.
1) The skin of the scrotum is
− rugose
− has no fat
− contains the dartos muscle (smooth muscle)
2) Has a midline raphe and is divided by a septum
3) The scrotum is lined by layers that surround/invest the testis and combine in the midline to form the scrotal septum
Identify the layers surrounding/investing the testes and combining in the midline to form the scrotal septum.
From superficial to deep:
- Skin
- Subcutaneous tissue (Superficial fascia): dartos muscle and fascia
- External spermatic fascia: from fascia of external oblique muscle
- Cremasteric muscle and fascia: Fibres and fascia of internal oblique muscle
- Internal spermatic fascia: from transversalis fascia
- Tunica vaginalis (visceral and parietal layers): from peritoneum
What are the main divisions of the scrotum ?
The scrotum is roughly divided into an anterior 1/3 & a posterior 2/3 in relation to its neurovascular supply.
Describe the innervation of the scrotum. What is the clinical significance of this ?
- Anterior 1/3: L1 with ilioinguinal and genitofemoral nerves
- Posterior 2/3: S2-3 via scrotal branches of the perineal branches of the pudendal nerve
This is significant if operating under regional anaesthesia!
Describe the arterial supply of the scrotum.
Anteriorly: External pudendal branches of the femoral artery
Posteriorly: Branches of the internal pudendal branch of the internal iliac
Describe the veinous drainage of the scrotum.
Veinous drainage mirrors arterial supply
Anteriorly: External pudendal veins to the great (long) saphenous vein
Posteriorly: Internal pudendal veins to the internal iliac vein
Describe the lymphathic drainage of the scrotum.
Lymphatic drainage is to the superficial inguinal nodes
Define hydrocele. How do we treat this ?
Fluid accumulation within the potential space present in the scrotum (between the layers of tunica vaginalis)
Drain the fluid, through aspiration using anterior or lateral approach to avoid.
What is the function of the testes ?
Ovoid glands which produces sperm and secretes testosterone (by Leydig cells) and inhibin (by Sertoli cells)
What is the function of the testes ?
Ovoid glands which produces sperm and secretes testosterone (by Leydig cells) and inhibin (by Sertoli cells). Also packed with seminiferous tubules in which spermatogenesis takes place.
Describe the coverings of the testes.
Each testis has a series of coats/tunics, from superficial to deep:
1) Tunica vaginalis
− visceral and parietal layers
− a potential space for movement of testis
− hydrocele can occur here
2) Tunica albuginea
− tough and fibrous
− maintains internal pressure to help sperm transport
− forms mediastinum and septae
3) Tunica vasculosa with branches of the testicular vessels
Describe the coverings of the testes.
Each testis has a series of coats/tunics, from superficial to deep:
1) Tunica vaginalis
− visceral and parietal layers
− a potential space for movement of testis
− hydrocele can occur here
2) Tunica albuginea
− tough and fibrous
− maintains internal pressure to help sperm transport
− forms mediastinum and septae
3) Tunica vasculosa with branches of the testicular vessels
Describe the path of sperm.
Sperm pass from the seminiferous tubules (that total about 500m in length) to the rete testis in its mediastinum and then via the efferent ductules to the epididymis
Define rete testis.
” anastomosing network of delicate tubules located in the hilum of the testicle (mediastinum testis) that carries sperm from the seminiferous tubules to the efferent ducts”
Describe the arterial supply of the testes.
Testicular artery from aorta at L2 (plus anastomosis with cremasteric artery and artery to ductus deferens)
Describe the veinous drainage of the testes.
Testicular vein starting as a pampiniform venous plexus (converge as left testicular vein draining into left renal vein and right testicular vein draining into the inferior vena cava)
Describe the lymphatic drainage of the testes.
Lymph to para-aortic (lumbar) nodes
Describe the innervation of the testes.
Sympathetic lesser splanchnic nerve, T10-11, with referred pain being peri- umbilical
Define cryptorchidism. When should we treat it ? How is it treated ? How likely is it to recur ? Why should we treat it ?
- Undescended testes.
- Should be treated when the patient is approximately 6 months old (because may descend by itself without interventions)
- Medical treatment, human chorionic gonadotrophins (hCG), or GnRH.
- Surgical treatment, orchiopexy (if medical treatment unsuccessful)
- Re-ascent can occur in up to 25% of treated patients
- Should treat it because risk of testicular cancer, and infertility.
Define retractile testes. What is the mechanism for this ? Should you be concerned for patient if he has this ?
A testicle that may move back and forth between the scrotum and the groin
- Mechanism: overactive creamaster muscle
- For most boys, the problem goes away sometime during or before puberty
How long is the epididymis ? What are the main parts of it ? What does it continue as ?
Approximately 6m long highly coiled tube
Head, body and tail
Continues as the ductus deferens