Male Reproductive Anatomy - BGDA Flashcards
Where do the testes initially develop?
High in the abdominal cavity near the kidneys
What is the gubernaculum?
A process that the testes follow as they descend
- bring with them part of the aponeuroses and fascia of the abdominal muscles
What are the surfaces of the testes?
Superior and inferior end, medial and lateral surface, and posterior and anterior margin
Where are the testes and epidydmis located?
Within the scrotum. Supported by the spermatic cord and the smooth dartos muscle of the scrotum
What covers the posterior margin of the testes?
Epididymis and lower part of spermatic cord
What is the tunica albuginea?
Fibrous outer covering of the testes that sends septa into the testes and divides it into lobules
What do the lobules do in testes?
Converge to form the mediastinum tests, which is a fibrous tissue continuous with the tunica albuginea
What is contained within each lobule?
1-4 seminiferous tubules which converge to straight tubules as they approach the mediastinum
What is rete testis?
This is a convoluted network formed by the straight tubules in the mediastinum. From the rete testis, efferent ductules project to the head of the epididymis
What is the tunica vaginalis?
- Closed sac
- remnant of the foetal processus vaginalis
- has both visceral and parietal layers
- fluid filled space between them is the sac of the tunica vaginalis
- visceral layer covers the tunica albuginea + parts of the epididymis
- parietal layer lines the internal spermatic fascia
What is the scrotum?
A cutaneous, fibromuscular sac containing the testes, epididymis and lower parts of the spermatic cord
What divides the scrotum into two halves?
Scrotal raphe
What is the skin of the scrotum like?
Thin and pigmented and overlies the dartos muscle, which sends a septum between the testes.
What are the layers deep to the dartos muscle?
External spermatic fascia, cremasteric fascia and internal spermatic fascia.
What is the cremasteric muscle?
Longitudinal muscle associated with the cremasteric fascia - it is involved in thermoregulation of the testes as they need to be kept cooler than the body.
What is the spermatic cord?
Conduit between testes and abdominal cavity
- contains vessels - testicular, cremasteric arteries and the artery of ductus deferens, testicular vein: pampiniform venous plexus and lymph vessels
- nerves - genital branch of genitofemoral nerve and its cremasteric nerve branch - supplies the cremaster muscle, testicular sympathetic and ductus deferens autonomic plexuses
What is the inguinal canal?
A passage through the abominal wall containing deep and superficial inguinal rings
What passes through the inguinal canal?
Ductus deferens, testicular and other small arteries, testicular veins (pampiniform plexuses), testicular lymph vessels and somatic and autonomic nerves
Where is the deep inguinal ring?
In the midinguinal point - halfway between the ASIS and the midline of the body
Where is the superficial inguinal ring?
1cm superior and 1cm lateral to the pubic tubercle.
What is the ductus deferens?
A continuation of the tail of the epididymis
- starts off torturous and becomes straighter
What is the course of the ductus deferens?
Goes through the inguinal canal, over the lateral pelvic wall, crosses the ureter and passes between the posterior surface of the bladder and the upper pole of the seminal vesicle.
What happens at the ampulla of the ductus deferens?
Sperm can collect here prior to ejaculation
How does the ductus deferens form the ejaculatory ducts?
By entering the prostate and joining with the duct of the seminal vesicle to form the ejaculatory ducts.
What are the ejaculatory ducts?
Short and open into the prostatic urethra on the colliculus seminalis of the urethra crest
What are the seminal vesicles?
Coiled tubular glands that produce fructose, fibrinogen and prostaglandins.
- do not store sperm
- lie lateral to the ampulla of the ductus deferens, posterior to the base of the urinary bladder and anterior to the rectum
What is the prostate?
A gland which surrounds the neck of the urinary bladder and upper urethra
- produces an alkaline solution
What is the structure of the prostate?
2 lateral lobes, a median lobe, posterior lobe and anterior segment
What are bulbourethral glands?
Two pea-shaped glands enclosed by fibres of the sphincter urethrae
- lie lateral to the membranous urethra
- opens on the intrabulbar fossa of the spongy urethra
What are key features of the penis?
- two crura covered by ischiocavernosus muscle
- bulb of penis lies between crura and covered by bulbospongiosus - spongy urethra passes through the bulb
- body of penis supported by two ligaments - fundiform and suspensory
Outline the corpora cavernosa
- continuous with the crura and enclosed in a fibrous tunica albuginea
- interior composed of numerous trabeculae arising from the fibrous sheaths of the corpora cavernosa
- between trabeculae are penile cavernous spaces or sinuses which fill with blood during erection
Where does blood enter the penis during an erection?
Central and helical arteries and leaves via peripheral veins
What is the corpus spongiosum?
Continuous with the bulb of the penis
- expands distally as the glans penis which has a ride known as the corona glandis
What is the glans of the corpus spongiosum covered by?
Prepuce and a frenulum
What lies on the corona glandis and penile neck?
Small preputial glands which secrete smegma
What is the physiological pathway of an erection?
Parasympathetic stimulation –> vasodilation of penile arteries –> inrush of blood into cavernous sinuses –> increase in intracavernous pressure –> compression of peripheral veins –> decrease in venous outflow –> increase in intracavernous pressure
What is the path of the testicular arteries?
Arise from the abdominal aorta just below renal arteries –> run through inguinal canal along spermatic cord
What do the testicular arteries supply?
Testes, cremaster muscles, iliac lymph nodes and other structures
What is the path of the inferior epigastric artery?
Forms the lateral umbilical fold, divides into numerous branches that anastomose with the superior epigastric and posterior intercostal arteries
What does the inferior epigastric artery supply?
Anterolateral abdominal wall muscles and parietal peritoneum
What does the inferior epigastric artery give rise to?
Cremasteric artery which supplies the cremasteric muscle and the scrotum.
How is the femoral artery formed?
External iliac artery passes under the inguinal ligament to become the femoral artery.
What does the femoral artery give rise to?
The external pudendal artery which supplies the scrotum.
Outline the superior vesicle arteries.
Several branches arising from the foetal umbilical artery
- supply the ureters and urinary bladder
- give rise to the arteries of the ductus deferens
Outline the inferior vesicle artery.
Arises from the internal iliac artery
- supplies the seminal vesicles, prostate gland and ejaculatory ducts (also ureters and urinary bladder)
Outline the middle rectal artery.
Arises from the internal iliac and supplies the seminal vesicles, prostate and rectum
What is the path of the internal pudendal artery?
Leaves the pelvis between the piriformis and coccygeus muscles to enter the pudendal canal.
What are the brances of the internal pudendal artery?
1) Muscular branches - supplies muscles of the pelvic diaphragm
2) Inferior rectal artery - supplies ischiorectal fossa and anal canal
3) Perineal artery - supplies muscles of the urogenital diaphragm
4) Urethral artery - supplies the urethra
5) Scrotal branches - supplies the scrotum
6) Artery of the bulb of the penis
7) Deep artery of the penis - supplies the sinuses of the penile crura and cavernosa via central and helical branches
8) Dorsal arteries of the penis - supplies the glans penis and the glans clitoris in females
What do the testicular veins do?
Drain the testes and epididymis - unite to form the pampiniform plexus that ascends along the testicular artery
Where do the testicular veins drain into?
R - IVC
L - renal veins
What are the key branches of the external iliac vein?
Inferior epigastric vein and femoral veins (external pudendal vein and superficial dorsal vein of the penis)
What does the inferior epigastric vein drain?
Lower anterolateral abdominal wall, peritoneum, spermatic cord and scrotum
What does the femoral vein receive?
Tributaries from the lower limb and lower abdominal wall
- also receives:
- external pudendal vein - draining the scrotum in males
- superficial dorsal vein of the penis - drains the penis into the great saphenous vein, and then into the femoral vein
Describe the lumbar ventral rami and plexus
Lumbar plexus arises from L2-4. L4-5 contribute to the sacral plexus via the lumbosacral trunk
What does the ilioinguinal nerve do?
Arises from L1 ventral ramus through the inguinal canal
- transmits sensory information from the scrotum and root of penis
What does the genitofemoral nerve do?
Arises from L1-2 ventral rami
- transmits sensory information from the scrotum via its genital branch
What is the sacral ventral rami and plexus?
Ventral rami of sacral spinal nerves join with lumbosacral trunk to form sacral plexus
- greater sciatic nerve arises from this
What does the posterior femoral cutaneous nerve do?
Arises from S1-3 ventral rami
- transmits sensory information from the scrotum via its perineal branch
Where does the pudendal nerve arise from?
S2-4 ventral rami
What does the dorsal nerve of the penis do?
Transmit sensory information from the corpora cavernosa, corpus spongiosum and glans penis
What does the perineal nerve do?
Sensory information from scrotum, spongy urethra
- motor signal to the muscles of the pelvic and urogenital diaphragms
What does the inferior rectal nerve do?
Sensory information from anal canal
- motor signals to the external anal sphincter
What are the main lymph nodes concerning the male reproductive system?
Lumbar lymph nodes, common iliac nodes, external iliac nodes and internal iliac and sacral nodes
What do the lumbar lymph nodes do?
Drain the testes, suprarenal glands, kidneys, abdominal ureter and posterior abdominal wall.
What do the common iliac nodes do?
Drain the rectum, external and internal iliac and sacral nodes
What do the external iliac nodes do?
Drain the prostate, seminal vesicles. Drain the scrotum and penis via the superficial and deep inguinal nodes
What do the internal iliac and sacral nodes do?
Drain the prostate and seminal vesicles as well as the scrotum and anal canal.
