15-03-23 - Male reproductive Organs 1 and 2 Flashcards
Learning outcomes
- Describe how the layers of the abdominal wall contribute to the fascial layers of the spermatic cord
- Describe the spermatic cord and state its contents
- Describe the anatomies (appearance, structure, function, neurovascular supply and lymph drainage) of male internal reproductive organs
- Describe the anatomies (appearance, structure, function, neurovascular supply and lymph drainage) of male external reproductive organs
- Describe the anatomy (position, structure, function, blood, nerve supply and lymph drainage) of the male urethra
- List the major constituents of seminal fluid and ejaculate and know where they are formed
- Discuss the clinical conditions that affect the male internal and external reproductive organs, as well as inguinal hernias
Review: Processus Vaginalis.
What cells do testes develop from?
Where do the testes originally develop?
Where do they migrate to?
What 4 structures do the tastes take with them when migrating?
What position do the testes sit in after birth?
- Review: Processus Vaginalis.
- Primoridal germ cells migrate from the endoderm of the yolk sac and meet with Sertoli support cells for testes development
- The testes develop in the lower thoracic region in the posterior abdominal wall
- During embryonic development, the testes migrate from the posterior abdominal wall through the anterior abdominal wall, through the inguinal canal & into the scrotum
- 4 Structures do the tastes take with them when migrating:
1) Ductus deferens
2) Testicular vessels
3) Loop of parietal peritoneum known as the processus vaginalis
4) Thoracic nerves - After birth, the tastes should lie as a closed potential space around the testes known as the tunica vaginalis
What is the role of the gubernaculum?
What can lead to an indirect inguinal hernia or a hydrocele?
- The gubernaculum shrinks to draw the testes down the posterior abdominal wall (outside the peritoneum) to the inguinal canal & then through the inguinal canal during the 8th & 9th months so that the testes are in the scrotum by birth
- If the proximal part of the tunica vaginalis stays open, it can lead to an indirect inguinal hernia or a hydrocele
What is the inguinal canal created by?
What is the inguinal canal?
- Inguinal canal (“tunnel”) created by the descent of the testes “pushing” through “some” of the layers of the abdominal wall
- 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 2 layers of tissue on the superficial abdominal wall?
When will these layers change names?
- 2 layers of tissue on the superficial abdominal wall:
1) Skin (Epidermis+dermis)
* Attached to subcutaneous tissue loosely except at umbilicus
2) Subcutaneous tissue (Superficial fascia, SF)
* Subcutaneous fatty layer (Camper’s fascia)
* Deep membranous layer (Scarpa’s fascia)
- These layers will continue over the perineum/scrotum and change names
Describe the parts of the male reproductive organs (in picture)?
What are the 2 types of parts in the male reproductive organs?
- Parts of the male reproductive organs (in picture)
- There are internal and external parts of the male reproductive organs
- The external part is the penis
What is the role of the scrotum?
Why does it do this?
Describe 3 features of the skin of the scrotum.
What type of muscle is the dartos muscle?
What is it supplied by?
How is the scrotum divided?
- The scrotum suspends the testes outside the body allowing for optimal thermoregulation with temperatures lower that the body core for normal spermatogenesis
- 3 features of the skin of the scrotum:
1) Rugose (wrinkly)
2) Has no fat
3) Contains the dartos muscle - The dartos muscle is smooth muscle, and causes the skin of the scrotum to be rugose
- It is supplied by sympathetic fibres in the genital branches of the genitofemoral nerves
- The scrotum has a midline raphe & is divided by a septum
What is the scrotum lined by?
What do these layers form?
What are the 6 layers of the scrotum from superficial to deep?
What layers are missing from the scrotum?
- The scrotum is lined by layers that surround/invest the testis & combine in the midline to form the scrotal septum
- 6 layers of the scrotum from superficial to deep:
1) Skin
2) Dartos muscle and fascia
3) External spermatic fascia: from fascia of external oblique muscle
4) Cremasteric muscle and fascia: Fibres and fascia of internal oblique muscle
5) Internal spermatic fascia: from transversalis fascia
6) Tunica vaginalis (visceral & parietal layers): from peritoneum
- There are no fascia or muscle fibres of the transverse abdominis in the scrotum
Scrotum diagram
How is the scrotum divided up in terms of neurovascular supply.
For the anterior and posterior scrotum, what is the:
1) Blood supply
2) Venous drainage
3) Nerve supply
4) Lymphatic drainage
- The scrotum is roughly divided into an anterior 1/3 & a posterior 2/3 in relation to its neurovascular supply
- For the anterior and posterior scrotum:
1) Blood supply
* Anteriorly: External pudendal branches of the femoral artery
* Posteriorly: Branches of the internal pudendal branch of the internal iliac
2) Venous drainage (mirrors arterial supply)
* Anteriorly: External pudendal veins to the great (long) saphenous vein
* Posteriorly: Internal pudendal veins to the internal iliac vein
3) Nerve supply
* Anterior 1/3: L1 with ilioinguinal & genital branch of 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!
4) Lymphatic drainage
* Lymphatic drainage is to the superficial inguinal nodes
What are hydrocoeles?
Where do they form?
How can they be aspirated?
- Hydrocoeles are a swelling in the scrotum
- They form between layers of the tunica vaginalis
- Aspirated by anterior or lateral approach to avoid posteriorly situated epididymis
What type of glands are the testes?
Where are they located, suspended and tethered by?
Which testis sits lower?
What is the role of the testes?
- The testes are ovoid glands
- The testes sit in the scrotum, suspended by spermatic cord, tethered by gubernaculum
- Left testis lower than right by about 1cm
- The roles of the testes are to produce spermatocytes & secrete testosterone (by Leydig cells) and inhibin (by Sertoli cells)
What are the 3 coats/tunics of each testis.
What is each layer like?
What is the role of each layer?
- 3 coats/tunics of each testis:
1) Tunica vaginalis
* Visceral & parietal layers
* A potential space for movement of testis
* Hydrocele if fluid accumulates
2) Tunica albuginea
* Tough & fibrous
* Maintains internal pressure to help sperm transport
* Forms mediastinum & septae
3) Tunica vasculosa with branches of the testicular vessels
Where does spermatogenesis take place?
Describe the movement/development of spermatocytes through the testes
- The testes are packed with seminiferous tubules in which spermatogenesis takes place
- Spermatocytes develop into spermatozoa while passing through the seminiferous tubules (that total about 500m in length) to the rete testis in its mediastinum & then via the efferent ductules to the epididymis
Describe the following supplies in the testes:
1) Blood supply
2) Venous drainage
3) Lymphatic drainage
4) Nerve supply
Where is testicular pain referred to?
- Supplies in the testes:
1) Blood supply
* Testicular artery from aorta at L 2 (plus anastomosis with cremasteric artery & artery to ductus deferens)
2) Venous drainage
* Testicular vein starting as a pampiniform venous plexus (converge as left testicular vein draining into left renal vein & right testicular vein draining into the inferior vena cava)
3) Lymphatic drainage
* Lymph to para-aortic (lumbar) nodes
4) Nerve supply
* Sympathetic lesser splanchnic nerve, T10-11, with referred pain being periumbilical
What is Cryptorchidism.
When should it be treated?
How often can re-ascent of testicles occur?
What 3 things can Cryptorchidism be treated with?
What complications can Cryptorchidism lead to?
- Cryptorchidism is the absence of at least one testicle from the scrotum due to not descending
- It should be treated when the patient is approximately 6 months old
- Re-ascent can occur in up to 25% of treated children
- 3 things can Cryptorchidism be treated with:
1) Human chorionic gonadotropin (hCG)
2) Gonadotropin-releasing hormone
3) Orchiopexy
* Surgery that moves an undescended testicle into the scrotum
- Cryptorchidism can lead to testicular cancer and infertility
What are retractile testes?
What are they caused by?
When can the problem be resolved?
- Retractile testes are when a testicle can move back and forth between the scrotum and the groin
- It is due to an overactive cremaster muscle
- For most boys, the problem goes away sometime before or during puberty
What is the epididymis?
What are the 3 parts of the epididymis?
What does it continue as?
What occurs in the epididymis?
How long are spermatozoa stored?
How is this done?
What occurs in the epididymis during ejaculation?
- The epididymis is an approximately 6m long highly coiled tube on the posterolateral aspect of each testicle
- 3 parts of the epididymis:
1) Head
2) Body
3) Tail - The epididymis continues as the ductus deferens
- Maturation and acquisition of motility of the spermatozoa take place in the epididymis
- Spermatozoa are stored up to 20 days
- This is done through CO2 being produced, which makes the environment acidic and reduces the spermatozoa’s motility
- During ejaculation, contractions of the smooth muscle on the wall of the epididymis expel mature spermatozoa into the ductus deferens
What is the ductus (vas) deferens?
Where is it found?
Describe the vas deferens route from the scrotum to the abdominal cavity.
Where does it lie in the pelvis?
- The ductus (vas) deferens is a Thick-walled, cord-like tube about 45cm long that carries spermatozoa from the testis & epididymis
- It is found posterior to the testis & medial to the epididymis
- The vas deferens leaves the scrotum & passes through the abdominal wall within the spermatic cord in the inguinal canal
- It emerges into the abdominal cavity lateral to the inferior epigastric artery
- It lies on the lateral wall of the pelvis
Where do the ductus (vas) deferens lie in relation to the pelvic vessels?
Where does it join with to form the ejaculatory duct?
- The ductus (vas) deferens lies medial to the pelvic vessels before passing antero-medially to the ureter (anterior to the rectum)
- It joins with duct of the seminal gland to form the ejaculatory duct
What are the 3 arteries and accompanying veins of the spermatic cord?
- 3 arteries and accompanying veins of the spermatic cord:
1) Testicular artery (& pampiniform venous plexus)
* Testicular artery (from aorta at L2)
* Pampiniform venous plexus (converge as left testicular vein draining into left renal vein & right testicular vein draining into the inferior vena cava)
2) Artery to ductus deferens (& accompanying vein)
* from inferior vesical artery
3) Cremasteric artery (& vein)
* From inferior epigastric artery
* Supplying the cremasteric fascia & muscle
What are the 3 tubes of the spermatic cord?
- 3 tubes of the spermatic cord
1) Ductus deferens
* Conveys spermatozoa from the epididymis to the ejaculatory duct
2) Lymphatic vessels from testes
* From testes to para-aortic [lumbar] nodes
3) Vestige (obliterated tube) of processus vaginalis
What are the 3 nerves of the spermatic cord?
Where does referred pain from the testes go to?
Why is testes pain carried alongside the sympathetics?
What is the cremasteric reflex?
- 3 nerves of the spermatic cord:
1) Genital branch of genitofemoral (L1/2)
* Supplying cremaster muscle
2) Sympathetics
* Derived from the lesser splanchnic nerve, T10-T11
3) Visceral afferents of the testes
* Referred pain is to the periumbilical region
- Testes pain is carried alongside the sympathetics because the testes develop above the pelvic pain line
- Cremasteric reflex (tests L1 – ilioinguinal nerve): Ipsilateral testicular retraction on stroking superior medial thigh
- The cremasteric muscle will contract and pull the testes towards the inguinal canal
Where can dilated & tortuous vessels in the testes occur?
What side foes it tend to occur on?
What kind of pain does it lead to?
What complications can dilated, tortuous veins lead to?
- Dilated & tortuous vessels in the testes can occur in the pampiniform venous plexus (feeling a bag of worms)
- Occurs almost always on the left side due to the almost right angle at which the left testicular vein drains into the left renal vein
- It can lead to dull, aching, or throbbing pain in the testicle
- Dilated and tortuous veins may lead to infertility
What is a vasectomy?
- A vasectomy is bilateral bisection of the ductus deferens
Where are the seminal glands (vesicles found)?
What is their role?
What forms the ejaculatory duct?
Where does the ejaculatory duct pas through?
- The left & right seminal glands (vesicles) lie just above the prostate gland between the bladder & rectum
- Their role is to secrete seminal fluid (contains fructose) to nourish sperm
- The dilated ampullary end of the ductus deferens unites with the duct from the seminal gland to form the ejaculatory duct that passes through the prostate gland to enter the urethra
What is the prostate?
What are the 4 surrounding structures of the prostate?
Where does the prostatic urethra descend through?
What does the prostate secrete at the time of ejaculation?
What else does it secrete?
- The prostate is a fibromuscular glandular organ that surrounds the urethra
- 4 surrounding structures of the prostate:
1) Inferior to the neck of the bladder
2) Posterior to the pubic symphysis
3) Anterior to the rectum
4) Superior to the urogenital diaphragm - The prostatic urethra descends through anterior prostate
- The prostate secretes, at the time of ejaculation, acidic cloudy fluid containing:
1) Prostaglandins
2) Acid phosphatase (PAP)
3) Proteolytic enzymes - The prostate also secretes prostate-specific antigen (PSA)
How many prostatic ducts are there?
Where do prostatic ducts open into?
What does the prostatic utricle open into?
What is on each side of the prostatic utricle?
- There are 20-30 prostatic ducts
- The prostatic ducts 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 centre of the seminal colliculus (remnant of female reproductive organs)
- On each side of the prostatic utricle is the openings of the Ejaculatory ducts
How is the prostate divided up into lobes?
What are the 5 lobes of the prostate?
Where are they each located?
Why are lobes often not used by clinicians?
- The prostate is Incompletely divided into 5 lobes
- 5 lobes of the prostate:
1) Median (middle) lobe: between urethra and ejaculatory ducts
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
- Lobes are often not used by clinicians because they are indistinct, so often zones are used
What are the 4 MacNeal’s Zones of the prostate?
How do these zones correspond to lobes of the prostate?
Where can BPH and prostate cancer occur in these zones?
- 4 MacNeal’s Zones of the prostate:
1) Transitional zone
* Corresponds to part of the anterior lobe
* Around urethra
* Anterior to ejaculatory ducts
* BPH (benign prostatic hyperplasia) commonly occurs here
2) Central zone
* Roughly corresponds to median lobe
* Posterior to transitional zone
* Contains ejaculatory ducts
3) Peripheral zone
* Corresponds to partially median, partially anterior, and big chunks of left and right lobes
* around transitional & central zones
* 70% of prostate cancer occurs here
4) Anterior zone
* BPH can occur here
MacNeal’s Zones diagram
BPH and prostate cancer diagram
What is the pH of semen (ejaculate)?
What does fructose provide for the spermatozoa?
What is the role of acid phosphatase in the semen?
- The pH of semen (ejaculate) is neutral and slightly alkaline
- Fructose provides fuel for anaerobic energy metabolism in the spermatozoa
- Acid phosphatase in the semen is mainly secreted by the prostate and cleaves choline from glycerophosphorylcholine
What is another name for the bulbo-uretheral gland?
Where is it located?
What is it surrounded by?
Where does it drain into?
What does it secrete?
- The bulbo-uretheral gland are known as Cowper’s gland
- It is a tiny gland located in the deep perineal pouch, postero-lateral to the membranous urethra
- Surrounded by transverse fibres of external urethral sphincter muscle
- The bulbo-urethral gland drains into the spongy urethra
- It secretes mucus before ejaculation and neutralize the pH of the urethra and lubricates the urethra
What is the penis?
What is the skin on it like?
What structure surrounds the whole penis?
How is the foreskin formed?
- The penis is the male organ of sexual intercourse
- It has dark and loose skin with no fat
- Superficial (Dartos) fascia (indistinct merging of Camper’s & 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
What is the foreskin?
What is it continous with?
How is smegma formed?
Where is there a frenulum on the penis?
Where is the ventral midline penile raphe?
What is it a remnant of?
What is balanitis? What is phimosis?
- The foreskin (or prepuce) is a fold of skin continuous with the glans & therefore also with the mucous membrane of the urethra
- Secretions of sebaceous glands in the foreskin form smegma
- There is a small frenulum ventrally between the foreskin & glans with increased sensation either side
- The skin & glans show a ventral midline penile raphe, which is a remannt of urethral folds fusing in the midline during devlopment
- Balanitis: Inflammation of the glans, which can occur due to lack of cleanin of smegma
- Phimosis: Prepuce that is too tight to retract
What parts does the penis consist of?
What does the body of the penis contain?
- The penis consists of a root and a free body that ends in an enlarged tip called the glans penis
- The body contains the spongy urethra and 3 long cylindrical bodies
What are the 3 long cylindrical bodies on the penis?
What are these cylindrical bodies surrounded by?
- 3 long cylindrical bodies on the penis:
1) 2 Corpora cavernosa (Cavernous bodies)
* Divided by a septum that is complete proximally, but pectiniform distally
* Each surrounded by thick tunica albuginea
* Has small caverns that are filled with blood during erection
2) Corpus spongiosum (Spongy body)
* Transmits the urethra
* Forms the glans as a cap over the Cavernous bodies
* Surrounded by thinner tunica albuginea
- Cavernous and spongy bodies are surrounded by deep penile (Buck’s) fascia
What does the Ischiocavernosus muscle surround?
What does the Bulbospongiosus surround?
What 2 structures does the Bulbospongiosus compress?
What is the role of the Ischiocavernosus and Bulbospongiosus muscles?
What are the 2 supportive ligaments of the penis?
- Ischiocavernosus muscle surrounds each root (crus)
- Bulbospongiosus surrounds the bulb of penis
- 2 structures the Bulbospongiosus compress:
1) Compresses the urethra during ejaculation
2) Compresses the urethra to expel urine - The Ischiocavernosus and Bulbospongiosus muscles support the penis & contribute to erection
- 2 supportive ligaments of the penis:
1) Fundiform ligament
2) Suspensory ligament
What are the 4 parts of the urethra?
Where are the internal and external urethral sphincters located?
- 4 parts of the urethra:
1) Preprostatic
* In bladder neck (part of bladde that surrounds the urethra
* Surrounded by internal urethral sphincter (smooth muscle; involuntary) – prevents retrograde ejaculation (ejaculate moving to bladder) through sympathetic mediated contraction
2) Prostatic
* Ejaculatory ducts opens
3) Membranous
* In deep perineal pouch
* Surrounded by external urethral sphincter (voluntary)
4) Spongy
* In bulb of penis (bulbar urethra) or
* Spongy body (penile urethra)
How narrow is the membranous part of the urethra?
What 2 structures is it located within?
Why is this?
- The membranous part of the urethra is the second narrowest part (first part is external meatus)
- 2 structures the membranous part of the urethra is located within:
1) The striated external urethral sphincter (slow twitch)
2) Pubourethral or puboprostatic part of levator ani (mixed slow & fast twitch) - This is to resist surges of raised intra-abdominal pressure
What does the spongy part of the urethra consist of?
What is the navicular fossa?
What are the 2 curvatures of the spongy part of the urethra when flaccid?
When do these curvatures disappear?
What must happen to these ureteral curvatures when passing a catheter?
- The spongy part of the urethra (longest part of urethra) consists of bulbourethral glands plus many scattered glands especially in navicular fossa (lacuna magna)
- The navicular fossa is the expansion of the urethra in the glans of the penis
- 2 curvatures of the spongy part of the urethra when flaccid:
1) Infrapubic curvature: Between membranous & bulbar urethra
2) Prepubic curvature: In the spongy urethra - These curvatures disappear during erection
- Urethral curvatures must be straightened when passing a catheter
What is the arterial supply of the prostate gland & proximal male urethra?
What does the prostatic venous plexus drain?
What does it also have connection with?
What does this mean in relation to prostate cancer?
- The prostate gland & proximal male urethra receive arterial supply via the Inferior vesical artery
- The prostatic venous plexus drains into internal iliac vein, and has connections with vertebral veins as well
- This means the first metastasis in prostate cancer is usually to the vertebrae
What is the lymphatic drainage of the urethra?
Where might the prostate lymph drain to?
- The lymphatic drainage of the urethra are the Internal iliac lymph nodes
- Prostate lymph may drain to presacral nodes too
Describe the following nerve supplies to the male reproductive organs:
1) Somatic motor control of external urethral sphincter
2) Autonomic
3) Visceral afferents (except testes)
4) Somatic afferents
- Nerve supplies to the male reproductive organs:
1) Somatic motor control of external urethral sphincter
* Pudendal nerve (S2-4) and its perineal branches
2) Autonomic
* Parasympathetics: from S2-4 to pelvic splanchnic nerves to inferior hypogastric plexus
* The parasympathetics are mainly for erection
* Sympathetics: from L1-2 to superior hypogastric plexus to inferior hypogastric plexus
* The sympathetics are for ejaculation, but also control the internal urethral sphincter to prevent retrograde ejaculation.
* Both come together to form a plexus
3) Visceral afferents (except testes)
* Via sacral parasympathetics (S2-4)
* Pain sensation for the internal male genitalia is carried alongside the parasympathetics
* Pain sensation for the testes is carried alongside the sympathetics, due to developing in the lower thoracic/lumbar region (above pelvic pain line)
4) Somatic afferents
* Pudendal nerve (S2-4) and its perineal branches
* Controls external genitalia and voluntary external urethral sphincter
Urethra diagram
