Anatomy of the Male Reproductive Tract Flashcards
What is the male reproductive tract in anatomical relationship with?
The urinary tract
What is the scrotum?
A cutaneous sac
What does the scrotum contain?
- Testis
- Epididymis
- First part of spermatic cord
What is the testis surrounded by?
The tunica vaginalis
What is the tunica vaginalis derived from?
Processus vaginalis
What is testis enclosed by?
Tunica albuginea
Are the testes enclosed within the peritoneal membrane?
No, sit behin it enveloped in an outpouching
What is the testis organised into?
Lobules
How is the testis organised into lobules?
By fibrous septae
What is found within the lobules of the testis?
Functional tissue of the testis
What happens to the testes during development?
They descend
What are the testes developed from?
Labioscrotal folds
What are the labio scrotal folds derived from?
Outpouchings of the anterolateral abdominal wall
Where do the gonads develop?
Within the mesonephric ridge, up in the abdomen in association with the kidneys
What course do the testes take during their descent?
- Descend through the abdomen, behind the peritoneum
- Cross the inguinal canal
- Exit the anterolateral abdominal wall
Are the testes palpable in the scrotum at delivery in a term pregnancy?
Yes
What is the arterial supply of the testes?
Direct branch of the abdominal aorta
Relates to their embryological origin
What is the venous drainage of the testes?
By the testicular vein, which drains into;
- IVC on right
- Renal vein on left
What is the innervation of the testes?
- Anterior surface by lumbar plexus
- Posterior and inferior surfaces by sacral plexuses
*
- Posterior and inferior surfaces by sacral plexuses
What does the lymphatics of the testes drain into?
The para-aortic nodes
Where does the lymphatics of the scrotum drain into?
The superficial inguinal nodes
Why is there a vast difference in the lymphatic drainage of the testes and the scrotum, despite them being close to each other geographically?
Because the testes develop on the posterior abdominal wall, and the drainage reflects that
What does the epididymis consist of?
- Head
- Body
- Tail
What does the epididymis do?
Connects to the seminiferous tubules via efferent ductules and rete testis
What does the spermatic cord contain?
Structures running to and from testes;
- Neurovascular structures
- Duct system
- Processus vaginalis
What neurovascular structures does the spermatic cord contain?
- Testicular artery
- Cremasteric artery
- Artery to vas
- Pampiniform plexus
- Genital branch of the genitofemoral nerve
What is the pampiniform plexus?
The beginning of the venous drainage, drains to testicular artery
What does the pampiniform plexus form?
A meshwork around the artery, ensuring optimum temperature for gametogenesis
What is the optimum temperature for gametogenesis?
Slightly lower than body temperature
How does the pampiniform plexus ensure optimum temperature for gametogenesis?
The veins form a heat exchange surface, so the blood that enters the testes is of a slightly lower temperature
Other than the pampiniform plexus, what else helps maintain the optimum temperature for gametogenesis?
The scrotum hanging lower than the body
What part of the duct system does the spermatic cord contain?
Vas deferens
What course does the vas deferens take?
- Ascends in the spermatic cord
- Transverses inguinal canal
- Tracks around pelvic side wall
- Passes between bladder and ureter
- Forms dilated ampulla
- Opens into ejaculatory duct
What is formed from specialisations of the dilated ampulla of the ductus deferens?
The seminal vesicles
What are the coverings of the spermatic cord?
- External spermatic fascia
- Cremasteric muscle and fascia
- Internal spermatic fascia
What is the external spermatic fascia?
The aponeurosis of the external oblique
Where does the cremasteric muscle and fascia come from?
The internal oblique and transversalis
Where does the internal spermatic fascia come from?
The transversalis fascia
What is the result of the oblique pathway of the spermatic cord through the inguinal canal?
There is a sequential building of the muscular and fascial layers
What path does the spermatic cord take?
The path that the testes take during development
From the deep inguinal ring and lateral to inferior epigastric vessels, to the posterior border testis, via the inguinal canal and superficial inguinal ring
What are the potential pathologies of the scrotum and its contents?
- Hydrocoele
- Haematocoele
- Spermatocoele
- Epididymitis
- Inguinal hernia
- Testicular torsion
What is a hydrocoele?
Serous fluid in the tunica vaginalis
How can a hydrocoele arise?
Becasue tunica vaginalis is derived from a serous peritoneal membrane, so normally produces a small amount of serous fluid. However, can get over production
What is a haemoatocoele?
Blood in the tunica vaginalis
What is a haematocoele typically a result of?
Trauma
What is a spermatocoele also known as?
An epididymal cyst
What is a spermatocoele?
A collection of developing spermatozoa
What is epididymitis?
Inflammation of the epididymis
What is epididymitis usually a consequence of?
Infection
What can be used to determine the type of swelling in the scrotum?
Transillumination
How can transillumination be used to determine the type of swelling in the scrotum?
- If swelling is fluid, allows light, so will transilluminate
- If swelling is solid, will not allow light, so won’t transilluminate
*
What are the types of inguinal hernias?
- Direct
- Indirect
Where does a direct inguinal hernia pass?
Through the inguinal wall
Where does an indirect inguinal hernia pass?
Through the inguinal canal, following the same pathway as the testes did during development
What is the developmental basis of an indirect inguinal hernia?
It is the reopening of the processus vaginalis, which should have nothing in it, but sometimes does and therefore can allow an intestinal loop to pass into the scrotum
What does a failure of closure of the tunica vaginalis produce?
A potential continunity between the peritoneal cavity and the tunica vaginalis, i.e. between the abdomen and the scrotum
What is testicular torsion?
Twisting of the testes around the spermatic cord
Where does testicular torsion most commonly occur?
Just above the upper pole
What can testicular torsion lead to?
May occlude the testicular artery, leading to ischaemia and risking necrosis of the testis
Where do the seminal vesicles lie?
Between bladder and rectum
Are the seminal vesicles a storage site?
No
What do the secretions of the seminal vesicles constitute?
70-80% of the ejaculate
What are the seminal vesicles formed from?
Diverticulum of the vas deferens
What does the duct of the seminal vesicle combine with?
The vas deferens
What is formed when the duct of the SV combines wih the VD?
The ejaculatory duct
What kind of gland is the prostate?
Fibromuscular
What important anatomical relationships does the prostate have?
- Base with neck of bladder
- Apex with urethral sphincter and deep perineal muscles
- Muscular anterior surface with urethral sphincter
- Posterior with ampulla of rectum
- Inferolateral with levator ani
What are the zones of the prostate?
- Central zone
- Peripheral zone
Where does the urethra run in relation to the prostate?
Through the centre of the body of the prostate
What can result from enlargement of the prostate?
Can compress the urethra
Why will varying states of enlargement compress the urethra?
Depends on where it is
Where does benign prostatic hypertrophy primarily affect?
The middle lobule
What does benign prostatic hypertrophy lead to?
Obstruction of the internal urethral orifice
What are the symptoms of benign prostatic hypertrophy?
- Dysuria
- Nocturia
- Urgency
Where do prostatic malignancies usually affect?
Outer lobes
What is the result of prostatic malignancies usually affecting the outer lobes?
They present later
How can prostatic malignancies metastasise?
- Lymphatic route
- Venous routes
What lymph nodes are involved in prostate cancer metastasise?
- Internal iliac
- Sacral
What veins are involved in prostate cancer metastases?
Internal vertebral plexus to vertebrae and brain
What does a digital rectal examination (DRE) allow?
Examination of the prostate gland
What does a DRE exploit?
The anatomical relationship of the prostate to the rectum
What does the penis consist of?
- Root
- Body
- Glans
What does the internal structure of the penis consist of?
- Pair of corpus cavernosa dorsally
- A single corpus spongiosum ventrally
What is the penis supplied by?
Branches of the internal pudendal arteries
What are the parts of the urethra?
- Pre-prostatic
- Prostatic
- Membranous
- Spongy
Which parts of the urethra are very short?
- Pre-prostatic
- Membranous
Which part of the urethra is the least distensible?
Membranous
Why is the membranous part of the urethra the least distensible?
Because the peritoneal membrane is a thick, membranous, fascial layer
When is the lack of distensibility of the membranous urethra important to consider?
Male catherisation
What is the blood supply to the male perineum?
Via the internal pudendal artery, which is a branch of the anterior divison of the internal iliac artery
What are the muscles of the male perineum?
- Bulbospongiosus
- Ischiocavernosus
What does the bulbiospongiosus do?
- Helps expel last drops of urine
- Helps maintain erection
What does the ischiocavernosus do?
Compresses veins, therefore helps maintain erection
