4) Anatomy of the Male Reproductive System Flashcards
What is the scrotum?
Cutaneous fibro-muscular sac for the testes and associated structures
Where is the scrotum located?
Posteroinferior to the penis
Inferior to the pubic symphysis
What does the mid-line scrotal raphe indicate?
The bilateral embryonic formation of the scrotum
What are the testes?
Male gonads
Paired, ovoid reproductive glands
Produce spermatozoa & male hormones
The tunica albuginea of the testes has a thick ridge posteriorly, what is this called & what is its function?
Mediastinum of the testis
Allows fibrous septums to extend inwards between lobules of seminiferous tubules
How do the testes arise?
Mesonephric ridge, upper lumbar regions, lower pole of kidneys
Tethered to labioscrotal folds (genital swellings, future scrotum) by the gubernaculum
Describe the descent of the testes
Move caudally
Musculo-fascial layer evaginates into scrotum as it develops + peritoneal membrane = Processus vaginalis
Testes cross the inguinal canal
Exit the anterolateral abdominal wall
What does the spermatic cord in males contain?
Fascial layers Processus vaginalis Vas deferens Lymphatics Testicular vessels & nerves
Where does the spermatic cord run?
Deep inguinal ring
Lateral to inferior epigastric vessels
Within the inguinal canal
Through superficial inguinal ring to posterior border of testis
What is the scrotal ligament a vestigial remnant of?
The gubernaculum
What is the arterial supply to the testes?
Abdominal aorta > Testicular arteries
Describe the course of the testicular arteries
Testicular a. arise from the abdominal aorta just inferior to the Renal a.
Pass retroperitoneally, cross over ureters & inferior part of external iliac arteries to reach deep inguinal rings
Pass through inguinal canal, superficial inguinal ring
Enter spermatic cords
What is the venous drainage of the testes?
Asymmetrical
Testes > Pampiniform Venous Plexus > Right testicular vein > IVC
Testes > Pampiniform Venous Plexus > Left testicular vein > Left Renal vein
The testicular vein wraps around the testicular artery. What is the significance of this?
Blood from abdominal aorta is cooled as it passes through the testicular artery
What are the 3 parts of the epididymis and what is its function?
Head (caput)
Body (corpus)
Tail (caudal)
Sperm transport, maturation (become motile) & storage
What is the innervation to the testes & scrotum?
Lumbar plexus - anterior surface
Sacral plexus - posterior & inferior surfaces
Why is the lymphatic drainage of the testes & scrotum different?
Linked to the different locations in which they developed
What is the lymphatic drainage of the testes & scrotum?
Testes - Drain to paraaortic nodes
Scrotum - Drain to superficial inguinal nodes
What is the function of the vas deferens?
Straight muscular tube within spermatic cord
Transports sperms rapidly to prostatic urethra
(autonomic innervation to smooth muscle permits rapid contractions)
During ejaculation which ducts dilate to facilitate sperm & semen secretions to the prostatic urethra?
Ejaculatory duct
Seminal vesicle
Describe the course of the ductus deferens
Ascends in spermatic cord Transverses inguinal canal Tracks around pelvic side wall Passes between bladder & ureter Forms a dilated ampulla & opening into ejaculatory duct
What neurovasculature is contained within the spermatic cord?
Testicular artery, cremasteric artery, artery to vas
Pampiniform plexus
Genital branch of Genitofemoral nerve
What are the 3 covering of the spermatic cord and where do they come from?
Anterolateral abdominal wall:
- External spermatic fascia (aponeurosis of external oblique)
- Cremasteric muscle & fascia (internal oblique & transversalis)
- Internal spermatic fascia (transversalis fascia)
Where do the seminal vesicles lie?
Posterior to the prostate
Between bladder & rectum
Describe the seminal vesicles
Small glands
Gland body - single highly convoluted tube, joins ampulla of ductus deferens to form ejaculatory duct
What is the function of the seminal vesicles?
Produce coagulated secretions
comprise 70-80% of volume of ejaculate
What are the borders of the prostate gland?
Base - Neck of bladder
Apex - Urethral sphincter & deep perineal muscles
Anterior surface - muscular urethral sphincter
Posteriorly - Ampulla of rectum
Inferio-lateral - Levator Ani
What important structure does the prostate gland surround?
Prostatic urethra
What secretions does the prostate gland produce?
Secretions contain:
Prostaglandins, proteolytic enzymes & citric acid
Form ~30% of volume of ejaculate
What is the location & function of the bulbourethral glands?
Located within urogenital diaphragm
Contain tubular & alveolar-type glands
Produce clear water secretion prior to ejaculation that may lubricate the urethra
Describe the structure of the penis
Root, body & glans
Internal structure:
Pair of corpora cavernosa dorsally
Single corpus spongiosum ventrally
What is the arterial supply to the penis?
Abdominal aorta > Common Iliac > Internal iliac > Anterior division of Internal Iliac > Internal Pudendal artery
What venous drainage supplies the penis?
Venous plexus of the Penis > Deep dorsal vein of the penis > Prostatic venous Plexus > Internal Iliac vein > Inferior Vena Cava
What are the 2 superficial muscles of the perineum?
Bulbospongiosus
Ischiocavernosus
What is the function of the bulbospongiosus?
Helps to expel last drops of urine & maintain erections
What is the function of the ischiocavernosus?
Compresses veins, helps maintain erections
The male urethra is divided into how many parts?
What are their names?
4 Pre-prostatic Prostatic Membranous Spony (penile)
Which is the least distensible part of the male urethra?
Membranous part
Passes through perineum & pelvic floor
Has greastest risk of trauma due to catheterisation
What is a hydrocoele?
Serous fluid in tunica vaginalis of scrotum
What is a haematocoele?
Blood in the tunica vaginalis of the scrotum
What is a varicocoele?
Varicosities of the pampiniform plexus in the scrotum
What is a spermatocoele?
Retention cyst within the epididymis
a.k.a. epididymal cyst
What is epididymitis?
Inflammation of the epididymal cyst
What is an indirect inguinal hernia?
Hernia indirectly into inguinal area, via inguinal canal, through deep inguinal ring
Lateral to inferior epigastric vessels
Reopening of processus vaginalis gives potential continuity between peritoneal cavity & tunica vaginalis
What is a direct inguinal hernia?
Hernia directly into inguinal area
Medial to inferior epigastric vessels
What is testicular torsion?
Twisting of the spermatic cord
Risk of necrosis of testis
Usually occurs above upper pole of testis
Why does cancer of the prostate often present later than benign prostatic hyperplasia (BPH)?
No urinary symptoms
Cancer cells more peripheral
Only occlude urethra at later stage
Which location does benign prostatic hyperplasia usually occur?
Central zone of prostate
What are the symptoms of benign prostatic hyperplasia?
Dysuria
Nocturia
Urgency
Where do prostatic malignancies usually occur?
Peripheral zone of prostate
Where do prostatic malignancies commonly metastasise?
Via lymphatics
Internal iliac & sacral nodes
& Venous drainage
Internal venous plexus to vertebrae & brain
Which antigen is elevated in prostatic disorders?
Blood levels of Prostatic-Specific Antigen
produced by abnormal prostatic epithelial cells
How can the prostate be examined?
Digital rectal examination (DRE)
Exploits anatomical relationship of prostate to rectum
