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
What are the main functions of the epididymis ?
During ejaculation, contractions of the smooth muscle on the wall of the epididymis expel mature spermatozoa into the ductus deferens
Maturation (in addition to in the semineferous tubules) and acquisition of motility (motility absent prior to epididymis) of the spermatozoa occurs here.
How long does sperm remain in the epididymis ?
Between 18 hours and 20 days
Describe the anatomical path of the ductus deferens.
Lies posterior to the testis and medial to the epididymis
Leaves the scrotum and passes through the abdominal wall within the spermatic cord in the inguinal canal
Emerges into the abdomen lateral to the inferior epigastric artery and lies on the lateral wall of the pelvis
Lies medial to the pelvic vessels before passing antero-medially to the ureter (anterior to the rectum)
Joins with duct of the seminal gland to form the ejaculatory duct
What is another name for ductus deferens ?
Vas deferens
How long is the ductus deferens ?
Thick-walled, cord-like tube about 45cm long
What is the main function of the ductus deferens ?
Carries sperm from the testis and epididymis to the ejaculatory duct
Identify the contents of the spermatic cord.
3 arteries (with accompanying veins/venous plexuses)
- Testicular artery and pampiniform venous plexus
- Artery to ductus deferens
- Cremasteric artery and vein
3 tubes
- Ductus deferens
- Lymphatic vessels from testes to para-aortic [lumbar] nodes
- Vestige (obliterated tube) of processus vaginalis
2 nerves
- Genital branch of genitofemoral (L1/2)
- Sympathetics (efferents and afferents to testes)
Identify the origin of each of the main vessels of the spermatic cord.
− Testicular artery (from aorta at L2)
− Artery of ductus deferens (from inferior vesical artery)
− Cremasteric artery (from inferior epigastric
artery)
Identify the accompanying veins/veinous plexus of the arteries in the spermatic cord.
1) Testicular artery
− Pampiniform venous
plexus (converge as left testicular vein draining into left renal vein and right testicular vein draining into the inferior vena cava)
2) Cremasteric artery
- Cremasteric vein
What does the cremasteric artery supply ?
Supplies the cremasteric fascia and muscle
State what each nerve in the spermatic cord innervates.
1) Genital branch of genitofemoral nerve
− supplying cremaster muscle
2) Sympathetic efferents and afferents
− to and from the testes
− derived from the lesser splanchnic nerve, T10-T11
Where does pain from the testes refer ? Why ?
Referred pain from the testes is to the periumbilical region, because sympathetic efferents and afferents to and from them are derived from T10-T11
Define cremasteric reflex. What nerve is involved with this ?
Cremasteric reflex (L1): Ipsilateral testicular retraction on stroking superior medial thigh
Identify and describe a condition which may affefct the Pampiniform venous plexus.
Varicose veins (dilated and tortuous vessel) (like feeling a bag of worms).
- Almost always on the L side due to the almost right angle at which the testicular vein drains into the L renal vein.
- Symptoms: Dull, aching or throbbing pain in the testicle. May lead to infertility
Define vasectomy.
Bilateral dissection of the ductus deferens.
Describe the anatomical location of the seminal glands. What is their function ?
R and L seminal glands AKA seminal vesicles, lie just above the prostate gland between the bladder and rectum.
Function: Secreting seminal fluid (contains fructose and choline) to nourish sperm
How does seminal fluid join sperm ?
The dilated ampullary end of the ductus deferens (containing sperm) unites with the duct from the seminal gland (containing seminal fluid) to form the ejaculatory duct that passes through the prostate gland to enter the urethra.
Identify the main glands in the male reproductive system.
- Testes
- Seminal vesicles
- Prostate
- Bulbourethral glands
What type of gland is the prostate ?
Fibromuscular glandular organ
Describe the anatomical location of the prostate.
- Surrounds the urethra
- Inferior to the neck of the bladder, posterior to the pubic symphysis, anterior to the rectum and superior to the urogenital diaphragm
- Prostatic urethra descends through anterior prostate
What are the main functions of the prostate ?
1) Secretes, at the time of ejaculation, alkaline fluid containing
− prostaglandins
− acid phosphatase
− proteolytic enzymes
2) Secretes prostate-specific antigen (PSA)
How many prostatic ducts are there ? Where do they open ?
20 to 30
-Open chiefly into the prostatic sinuses that lie on either side of the seminal colliculus (verumontanum) on the posterior wall of the prostatic urethra
- Prostatic utricle opens onto the center of the seminal colliculus
- On each side of the prostatic utricle is the opening of the Ejaculatory ducts
Identify the main parts of the prostate. State which of these is more likely to be affected by a pathology.
♠ Incompletely divided into 5 lobes (but no histological boundary):
1) Median (middle) lobe: between urethra and ejaculatory ducts
− usually where prostate affected by BPH
2) Posterior lobe: Behind urethra, inferior to ejaculatory ducts
3) Anterior lobe: Anterior to urethra.
−Has no glandular tissue
4) Left and right lobes: On both sides of the urethra
♠ Also divided into MacNeal’s Zones:
1) Transitional zone, around urethra, anterior to ejaculatory ducts
- usually where prostate affected by BPH
2) Central zone, posterior to transitional zone, contains ejaculatory ducts
3) Peripheral zone, around transitional and central zones
- usually where prostate is affected by cancers
4) Anterior zone
Identify the main pathologies affecting prostate. Which parts of the prostate is affected by each of these ?
- Inflammation (anywhere)
- BPH (transitional zone)
- Cancer (peripheral zone)
Patient diagnosed with BPH, treated for that, then a few years later comes back with cancer. Is it doctor’s fault ?
No, different zones of the prostate are involved so not his fault
Identify any other names given to BULBO-URETHRAL GLANDS.
Cowper’s gland
Describe the anatomical location of bublo-urethral glands.
Located in the deep perineal pouch, postero-lateral to the membranous urethra.
Surrounded by transverse fibres of external urethral sphincter muscle
What are the main functions of the bulbo-urethral glands ?
Secretes mucus before ejaculation and neutralize the pH of the urethra and lubricates the urethra
Where does the bulbo-urethral glands drain ?
Drains into the spongy urethra
What is the penis ?
Male organ of sexual intercourse
Describe the skin and fascia of the penis.
- Dark and loose skin with no fat
- Superficial (Dartos) fascia (indistinct merging of Camper’s and Scarpa’s) surrounds whole penis
- The skin “doubles back on itself” to form the foreskin or prepuce that is continuous with the glans at the corona
Describe the main structural features of the penis.
- Consists of a root and a free body that ends in an enlarged tip called the glans penis
- Body contains the spongy urethra and 3 long cylindrical bodies
- The foreskin or prepuce is a fold of skin continuous with the glans and therefore also with the mucous membrane of the urethra
- There is a small frenulum ventrally between the foreskin and glans with increased sensation either side
- The skin and glans show a ventral midline penile raphe
Identify any glands in the penis.
Secretions of sebaceous glands in the foreskin form smegma
Identify pathologies of different parts of the penis.
Balanitis: Inflammation of the glans
Phimosis: Prepuce that is too tight to retract
Identify the cylindrical bodies making up the body of the penis.
1) Corpora cavernosa (Cavernous bodies)
− Divided by a septum that is complete proximally, but pectiniform distally
− Each surrounded by thick tunica albuginea
− Filled with blood during erection
2) Corpus spongiosum (Spongy body)
− Transmits the urethra
− Forms the glans as a cap over the Cavernous bodies
3) Cavernous and spongy bodies are surrounded by deep fascia (Buck’s)
Identify the muscles and ligaments of the penis.
• Ischiocavernosus muscle surrounds each root (crus)
− support the penis and contribute to erection
• Bulbospongiosus surrounds the bulb of penis
− support the penis & contribute to erection
− compressing the urethra during ejaculation
− compressing the urethra to expel urine
• Fundiform ligament and suspensory ligament are the supportive ligaments
Identify the main parts of the urethra, noting the main feature of each.
1) Preprostatic (internal urethral sphincter)
− In bladder neck
− Surrounded by internal urethral sphincter (smooth muscle; involuntary)
• Prevents retrograde ejaculation
2) Prostatic
− Ejaculatory ducts opens
3) Membranous
− Surrounded by external urethral sphincter (voluntary)
4) Spongy
− In bulb of penis (bulbar urethra) or
− Spongy body (penile urethra)
What are the main features of the spongy urethra ?
♦ Bulbourethral glands plus many scattered glands especially in navicular fossa (lacuna magna)
♦ Navicular fossa is the expansion of the urethra in the glans of the penis
♦ Has 2 curvatures when flaccid
− Infrapubic curvature: Between membranous and bulbar urethra
− Prepubic curvature: In the spongy urethra (disappears during erection)
What is the significance of urethral curvatures clinically ?
Urethral curvatures must be straightened when passing a catheter
Which of the parts of the urethra is the narrowest ?
Membraneous urethra (except for urinary meatus, so technically membraneous urethra second narrowest part)
What are the main features of the membraneous urethra ?
- Second narrowest part of the urethra
- Within the striated external urethral sphincter (slow twitch) and pubourethral or puboprostatic part of levator ani (mixed slow and fast twitch) to resist surges of raised intra-abdominal pressure
- The external urethral sphincter is actually shaped like an inverted pear with its base on the perineal membrane and its apex pushing up into the prostatic urethra
Describe the arterial supply and veinous drainage of the prostate and urethra.
- Prostate gland and proximal male urethra received arterial supply via the Inferior vesical artery
- Prostatic venous plexus drains (prostate) into internal iliac vein (has connections with vertebral veins as well)
Describe the lymphatic drainage of the prostate.
- Internal iliac lymph nodes
- Prostate may drain to presacral nodes too
Describe the nerve supply of the penis.
1) Somatic motor for control of external urethral sphincter
− Pudendal nerve (S2-4) and its perineal branches
2) Autonomic
− Parasympathetics: from S2-4 to pelvic splanchnic nerves to pelvic plexus
− Sympathetics: from L1-2 to superior hypogastric plexus to pelvic plexus
3) Somatic sensation
− Pudendal nerve (S2-4) and its perineal branches
Identify the male reproductive organs.
Penis Ductus Deferens Testes Epididymis Scrotum Bublourethral gland Prostate Seminal gland
