Lecture 8: Male genital system (testis and scrotum) Flashcards
Male genital system
- Internal genital organs
Testes
Epididymis
Ductus deferens Seminal glands Ejaculatory ducts Prostate Bulbourethral glands
Male genital system
- External genital organs
Scrotum Penis
Male external genitalia is located in
Urogenital triangle
Why are testis and epididymis considered as internal genitalia?
because of embryology.
The testes are the male
gonads
The testes produce
sperm and hormones (testosterone).
Location of the testes
in the scrotum, suspended by the spermatic cords
Surface of testis covered by
tunica vaginalis
tunica vaginalis:
double layer of peritoneum.
* Visceral layer closely applied to testis, epididymis, and inferior part of ductus deferens.
* Parietal layer extends onto distal part of spermatic cord.
* Cavity with fluid in between – allows movement of testis in scrotum.
Tunica albuginea: of testes
- Tough fibrous outer layer of testis.
- Forms mediastinum of testis: thickened ridge on internal, posterior aspect.
- From mediastinum, fibrous septa extend between seminiferous tubules of testis.
Seminiferous tubules: of testes
- Highly coiled tubes, where sperm are produced.
- Joined by straight tubules to the rete testis (in mediastinum)
- Retes testis connected to epididymis by efferent ductules.
Arterial supply of the testes
- Testicular artery:
➢Arises from abdominal aorta
inferior to renal arteries.
➢Pass retroperitoneal, cross over ureters and inferior parts of the external iliac arteries to reach deep inguinal ring.
➢Enter inguinal canal through deep ring.
➢Exit through superficial ring & enters spermatic cord.
➢Anastomoses with artery of the ductus deferens.
Venous drainage of the testes
- Veins from testis and epididymis form the pampiniform plexus in spermatic cord.
➢8-12 veins lying anterior to ductus deferens & surrounding testicular artery.
➢Thermoregulatory function: keep testis at optimal temperature for spermatogenesis. - Pampiniform plexus veins form the testicular veins:
- right testicular vein drains into inferior vena cava.
- left testicular vein drains into left renal vein
Innervation of testis
- Autonomic nerves:
➢Testicular plexus of nerves
on the testicular artery.
➢Contains sympathetic and visceral afferent fibers from T10(-T11); parasympathetic from Vagus nerve.
Lymphatic drainage of testis
Right and left lumbar (caval/aortic) and pre- aortic lymph nodes.
The epididymis is an
Elongated structure on the posterior surface of testis
Efferent ductules (of the epididymis) function
transport sperm from rete testis to epidiymis.
The epididymis is composed of
of a tightly packed convoluted duct
The epididymis consists of
➢ Head: superior expanded part.
➢ Composed of lobules from the coiled ends of 12-14 efferent ductules.
➢ Body: major part, convoluted duct.
➢ Tail: continues as the ductus deferens (duct that transports sperm to the ejaculatory duct).
Vas (ductus) deferens structure:
Thick-walled muscular tube, thin lumen
Vas (ductus) deferens course
- originates from tail of epididymis at inferior pole of testis.
- Ascends posterior to testis, medial to epididymis.
- Travels through spermatic cord.
- Passes through anterior abdominal wall in the inguinal canal.
- Courses over external iliac vessels & enters pelvis.
- Passes on lateral wall pelvis, underneath parietal peritoneum.
- Crosses superior to ureter near posterolateral angle of bladder → joins duct of seminal vesicle to form ejaculatory duct.
- Ampulla: enlarged part before its termination.
Seminal vesicles/glands is an _______ structure
Elongated
Seminal vesicles/glands located
between fundus of bladder and rectum
Seminal vesicles/glands orientated
obliquely superior to the prostate gland
Superior ends of the seminal vesicles/glands are
posterior to ureters & covered by peritoneum.
Superior ends of the seminal vesicles/glands separated from the rectum by
rectovesical pouch
Inferior ends of the seminal vesicles/glands are closely related to
ectum, separated by rectovesical septum.
Seminal vesicles/glands produces
alkaline fluid with fructose (nutrition) and coagulating substance.
Forms ejaculatory duct
Duct of seminal vesicle joins ductus deferens
Ejaculatory ducts Arise from
the union of seminal vesicle & ductus deferens:
Near neck of bladder, pass through posterior part of prostate gland.
➢Open into urethra on seminal colliculus, lateral to prostatic utricle (refer to prostate lecture).
Scrotum is a
Cutaneous fibromuscular sac containing testes and epididymi.
The scrotum consists of 2 layers:
skin & dartos fascia (continuous Scarpa’s fascia of anterior abdominal wall) which contains dartos muscle
dartos muscle function (of scrotum)
Contracts to wrinkle skin (thermoregulation)
Scrotum location
Posteroinferior to penis and inferior to pubic symphysis.
Scrotum is divided into two compartments by
the septum (derived from dartos fascia)
Midline scrotal raphe
is external marking of septum– continuous with penile raphe and perineal raphe.
- Line of fusion of labioscrotal swellings
Lymphatic drainage of scrotum
to superficial inguinal nodes.
Spermatic cord begins at
deep inguinal ring, passes through inguinal canal, exits via superficial inguinal ring ends scrotum at posterior border of testis
Spermatic cord contains
structures running to or coming from testes, suspends testes in scrotum.
Contents of spermatic cord
- Ductus deferens.
- Arteries (testicular, ductus deferens, cremasteric).
- Veins (pampiniform plexus, testicular, cremasteric).
- Nerves (sympathetic & parasympathetic, genital branch of genitofemoral, ilioinguinal).
- Lymphatic vessels.
Lymphatic drainage of testis
lymphatic drainage into right & left lumbar and pre-aortic nodes (travel with testicular artery and vein).
Lymphatic drainage of scrotum
drain into superficial inguinal nodes.
Bulbourethral glands location
Posterolateral to urethra, embedded in the external urethral sphincter
Bulbourethral glands ducts
pass through perineal membrane and open into spongy urethra at the bulb of the penis.
Bulbourethral glands ducts functions
Mucous secretion into urethra during sexual arousal.
