Lecture 21: Male Reproductive System Flashcards
Remainder of mesonephric duct becomes?
the ductus (Vas) deferens and ejaculatory duct.
The proximal mesonephric duct in a embryo becomes what?
epididymis
Maculinisation of external genitalia ONLY in presence of?
testosterone
Testicular descent: 7 months: testosterone stimulates?
descent of testes from pelvis to scrotum.
Testicular descent:
Descent guided by what?
gubernaculum extending from testis to floor of scrotal sac.
Testicular descent:
Drags supplying blood vessels and nerves along behind, this forms what?
spermatic cord
The penis is made up of three major structures, what are these?
• Root (crura, bulb, ischiocavernosus and bulbospongiosus
muscles)
• Body.
• Glans.
The penis has three cylinders of cavernous tissue, what are these?
2x corpora cavernosa (dorsal*)
1x corpus spongiosum (ventral*).
What is the blood supply, venous drainage and Innervation of the penis?
Blood supply: internal pudendal arteries, external pudendal arteries, deep arteries, arteries of the bulb (mainly dorsal arteries).
Venous drainage: deep and superficial dorsal veins
Innervation: dorsal nerve of the penis ( branch of pudendal)
Venous drainage of the penis?
deep and superficial dorsal veins.
Why is he dorsal vein of the penis names this when it sits on the ventral aspect?
Because when the penis is erect, the vein sits on the dorsal surface
What are the layers of the scrotum?
- Skin
- Dartos fascia and dartos muscle
- External spermatic fascia
- Cremaster muscle
- Cremasteric fascia
- Internal spermatic fascia
- Tunica vaginalis (parietal)
- Tunica vaginalis (visceral)
- Tunica albuginea (innermost layer covering testis)
The testis are suspended in the scrotum by what structure?
Spermatic cord
What is tunica vaginalis?
visceral & parietal layers of peritoneum around testes
What is tunica albuginea?
“white coat” tough fibrous outer surface of testis.
Tunica albuginea forms what inside testis?
Septa
What is the route of mature spermatozoa?
Mature spermatozoa move from seminiferous tubules through rete testis and efferent ductules to be stored in the epididymis awaiting ejaculation
Blood supply of testes?
- Testicular arteries
* Artery of ductus deferens
Venous drainage of testes?
- Pampiniform plexus to right testicular vein to IVC
* Pampiniform plexus to left testicular vein to Left renal vein.
Spermatic cord contains what structures?
- Ductus deferens
- Testicular artery
- Artery of ductus deferens
- Cremasteric artery
- Pampiniform plexus
- Sympathetic nerve fibres
- Genitofemoral nerve
- Lymphatic vessels
The spermatic cord has three coverings, what are these?
- Internal spermatic fascia
- Cremasteric fascia
- External spermatic fascia
The cremasteric fascia is derived from what?
Derived from fascia of internal obliques and contains loops of cremaster muscle
The internal spermatic fascia is derived from what?
derived from transversalis fascia
The external spermatic fascia is derived from what?
derived from external oblique aponeurosis and fascia
Cremaster muscle innervated by?
genitofemoral nerves (L1-L2)
Spermatic Cord begins where?
deep inguinal ring lateral to inferior epigastric vessels.
The spermatic cord exits at?
superficial inguinal ring.
The spermatic cord ends where?
in scrotum at posterior pole of testis
The vas deferens crosses over what structure to enter the pelvis?
External iliac vessels
Seminal VESICLE is located where in relation to the bladder, rectum and prostate?
Posterior to bladder
Anterior to rectum
Superior to prostate
What do the seminal VESICLE secrete?
thick alkaline fluid with fructose and coagulating agent that
mixes with sperm as they enter the ejaculatory duct and urethra
Ejaculatory Ducts formed by union of what two structures?
ducts of seminal vesicles with ductus deferens
Prostatic secretions join seminal fluid in prostatic
urethra AFTER what?
ejaculatory ducts have terminated
Prostatic secretion secretes what structure?
1/3 of semen volume; milky, slightly acidic contains citrate and
enzymes that activates sperm.
Prostatic secretion goes where?
Enters prostatic urethra via ducts when prostatic smooth muscle contracts during ejaculation.
Name a condition of the prostate?
Benign hypertrophy of the prostate (BHP) is common after middle
age.
Enlarged prostate projects into urinary bladder and distorts
prostatic urethra impeding urination
What happens to urination due to an inflamed prostate?
Enlarged prostate projects into urinary bladder and distorts prostatic urethra impeding urination
What is a TURP and what does it involve?
Transurethral resection of prostate. Involved sectioning and removing parts of the prostate through the penis with no external incision
Bulbourethral Gland Innervation?
Under parasympathetic stimulation: Secrete clear mucous-like fluid during sexual arousal which neutralises traces of acidic urine in the urethra and lubricates glans penis.
Name the four parts of the male urethra?
- Intramural
- Prostatic part [3-4 cm]
- Intermediate
- Spongy urethra [15cm]
Innervation of internal genital organs of the male? Sympathetic and parasympathetic
• Pre-synaptic sympathetic fibres originating from T12-L3
to sympathetic trunk to lumbar splanchnic nerves/hypogastric and pelvic plexuses.
• Pre-synaptic parasympathetic fibres originate from S2-S3 to
pelvic splanchnic nerves to inferior hypogastric/pelvic plexuses.
Synapses with post-synaptic sympathetic/parasympathetic neurons occur within plexuses.
Ductus deferens, seminal vesicles, ejaculatory ducts and prostate richly innervated by what type of fibres?
Sympathetic fibres
What is the processes of erection?
• Parasympathetic stimulation ↓ • Nitric oxide release ↓ • Relaxation (dilation) of vascular smooth muscle ↓ • Engorgement of erectile bodies with blood (compresses drainage veins -> retards blood outflow)
What is the processes of ejaculation?
• Ducts and glands contract to empty secretions—>internal urethral sphincter closes(sympathetic via lumbar splanchnic nerves) —-> bulbospongiosus muscles contracts from pudendal nerves—->peristaltic-like contractions of ductus deferens via sympathetic stimulation
What is the Innervation of the testes?
Posterior scrotal nerve
