Male reproductive system Flashcards
What are the three parts of the male urethra?
Prostatic part
Membranous part
Penile part
What are the sites of spermatozoa production?
Coiled seminiferous tubules
What part of the epididymis is connected to the superior part of the testis?
Head
Where do the coiled seminiferous tubules drain?
Rete testis
Where does the rete testis drain?
Tubules - vasa efferentia
Where do the vasa efferentia drain?
Coiled duct of epididymis
What does the epididymis become as it moves away from the testis?
Vas deferens
How does the vas deferens reach the urethra?
Enters spermatic cord, passes through inguinal canal.
Which surface of abdominal wall do the testes develop in the embryo?
Posterior
What occurs the the developing testis during development?
The descend obliquely
As testis descend what do they pass through?
Muscle layers of anterior abdominal wall
What anatomical feature does the testicle descent form?
Inguinal canal
When do testes complete their descent?
A few weeks before birth
What is the initial out-pouching initiating the descent of testes called?
Processus vaginalis
What layers does the testicle acquire as it descends?
Processus vaginalis
Transversalis fascia
Internal oblique muscle
Aponeurosis of external oblique
Why does the transversus abdominus not contribute to the layers acquired by the descending testicle?
Processus vaginalis passes below the arch formed by these muscle fibres.
What guides the testes in their descent?
Gubernaculum
In the adult, what four layers cover the testis and epididymis and what are they derived from?
Tunica vaginalis (as embyro)
Internal spermatic fascia (transveralis fascia)
Cremaster muscle (internal oblique)
Outer external spermatic fascia (from apopneurosis of external oblique)
What innervates the cremaster muscle ?
Genital branch of he genitofemoral nerve
What is the role of the outer muscular fascia of the testicle?
Work in concert to regulate the temperature of the testis, which needs to be slightly cooler than body temperature for optimum spermatogenesis.
They also draw the testes close to the body as a protective response.
What divides the scrotum internally into left and right compartments?
Dartos fascia
What artery supplies each testis?
Testicular artery, a branch of abdominal aorta
How does blood drain from the testicles into one single vein (on each side)?
Testicular veins form a convoluted pampiniform plexus, which forms three or four veins in the inguinal canal which then ultimately unite to form a single vein.
Where does the left testicular vein drain?
Left renal vein
Where does right testicular vein drain?
Directly to IVC
What nerves supply the smooth muscle of the vessels in spermatic cord?
Sympathetic
What spine roots to the sympathetic nerves come from that innervate the spermatic cord?
L1-L2
What spinal level do visceral afferents from the spermatic cord reach?
T-10
What nerve innervates the motor of cremaster and sensory of anterior scrotum?
Genital branch of Genitofemoral
Level of gential branch of genitofemoral nerve?
L1-L2
What fibres innervates the dartos muscle?
Sympathetic fibres
What nerve travels through part of the inguinal canal, but is not contained within the spermatic cord?
Ilioinguinal nerve (L1)
What is the embryological origin of the vas deferens?
Mesonephric duct
How does the vas deferens enter the pelvic cavity?
Deep inguinal ring
What is the ejaculatory duct?
Where the seminal vesicle joins the vas deferens
Where do the ejaculatory ducts feed into?
The prostatic part of the urethra
What supplies the smooth muscle in the walls of the ducti deferentes, seminal vesicles and ejaculatory ducts in order for contractions?
Sympathetics
Why is contraction of the vas deferens, and seminal vesicle essential?
Allows normal ejaculation of semen
Do seminal vesicles store sperm?
No
What do seminal vesicles store?
Thick alkaline fluid containing fructose
Why do seminal vesicles store fructose?
Energy source for sperm
What % of seminal fluid are the seminal vesicles responsible for secreting?
70%
Is the prostate superior or inferior to the bladder?
Inferior
What part of the urethra does the prostate surround?
The prostatic part
Where do the ducts of the gladular parts of the prostate open into?
The prostatic ureter
What are the glandular components of the prostate are surrounded by?
A fibromuscular stroma, a composite of smooth muscle and fibrous connective tissue
What innervates the prostate?
Sympathetic stimulation
What does contraction of the smooth muscle of the prostate cause?
Contraction adds the prostatic secretions to the ejaculate
What % of seminal fluid is the prostate responsible for?
30%
Why is seminal fluid alkali?
Neutralise the acidity of the vagina
What anchors the prostate anteriorly?
Puboprostatic ligaments
What anchors the prostate laterally?
Condensations of the pelvic fascia
Where does lymph drain from the testis?
Para-aortic nodes
Where does Lymph drain from seminal vesicles, prostate, ducti deferentes and deep / proximal structures of the penis ?
Internal iliac lymph nodes.
Where does Lymph drain from the superficial penis (e.g. skin) and scrotum ?
Superficial inguinal lymph nodes
Where does lymph drain from the glans of the penis and distal spongy urethra?
Deep inguinal nodes
What is the corpora cavernosa?
Mass of erectile tissue that runs left and right laterally in penis
Where are the crus of the corpus cavernosa of the penis attached to ?
Ischiopubic ramus
What is the proximal corpus spongiosum attached to ?
The perineal membrane
What forms to root of the penis?
The bulb and crura
What is the proximal part o f the corpus spongiosum known as?
The bulb
What are the proximal parts of the corpus cavernosum known as
The crura
What lies at the distal end of the corpus spongiosum?
The glans
What covers each crus?
Ischiocavernosus muscle
What does the ischiocavernosus muscle do?
Force blood from the crura into the distal parts of the corpus cavernosum, increasing the distension of the penis during erection and compressing the veins leaving the crus of the penis, restricting venous outflow, maintaining erection.
What muscle covers the bulb?
Bulbospongiosus muscle
What does bulbospongiosus do?
Assists in the emptying of the spongy urethra of residual urine or semen.
What are the three main superficial perineal muscles?
Superficial transverse perineal muscles
Ischiocavernosus muscle
Bulbospongiosus muscle.
What three cylinders of erectile tissue does the body of the penis contain ?
Two corpora cavernosa lying adjacent to each other
Corpus spongiosum lying ventrally
Which mass of erectile tissue surrounds the urethra?
Corpus spongiosum
Where is the foreskin attached?
The junction between the glans and the body
What separates the blood spaces in erectile tissue?
Trabeculae of fibrous tissue and smooth muscle
What artery supplies the erectile tissue of the penis?
Deep branch of the pudenal artery
What artery supplies the superficial tissues of the penis?
Dorsal branch of the pudenal artery
What veins drain the deep and superficial tissues of the penis?
Dorsal veins
In the relaxed state does blood flow through the helicine arteries and blood sinuses?
No
What nervous stimulation leads to eretion?
Parasympathetic (not pudendal) S2-S4
What does the parasympathetic innervation do in the penis?
Causes muscular walls of the spiral arteries relax, resulting in increased blood flow to the vascular spaces in the corpora.
What does increased blood flow in the penis cause?
Increasing pressure not only generates turgidity of the tissue, but also impairs venous return and results in further distension.
As a result of the increased blood in the corpora and the arrangement of fibrous tissue around them, the penis becomes erect (tumescence).
What innervation leads to the contraction of the bulbospongiosus and ischiocavernosus muscles?
Somatic pudenal nerve
What innervation causes the peristaltic contraction of vas deferens (emission)?
Sympathetic L1-L2
What nerve control triggers ejaculation?
Primarily somatic pudenal S2-S4
What occurs in ejaculation?
Rhythmic contraction of the bulbospongiosus muscle, the action of which is to expel semen from the bulb of the penis, along the spongy urethra and through the external urethral orifice.
What prevents backflux of semen into the bladder during ejaculation?
The internal urethral sphincter closes
What branches does the internal iliac artery (anterior branch) give in males?
Umbilical artery
Superior vesical arteries
Obturator artery
Internal pudendal artery
The inferior vesical artery (supplies the bladder, seminal vesical and prostate)
How does the internal pudenal artery gain access to the perineal region?
Enters the lesser sciatic foramen
What 3 branches does the internal pudenal artery give off?
Supply the superficial anal region
The inferior rectal artery
Perineal artery supplies the superficial musculature of the perineum as well as the posterior scrotum.
What artery supplies the anterior scrotum?
External pudenal artery
Is the testis attached to the scrotal sac? If so where?
yes, Posterior wall
Describe scrotal blood supply?
Posterior - internal pudenal
Anterior - exterior pudenal
Where does testis lymph drain?
Testis lymph drains to para-aortic nodes around the origin of the testicular arteries from the aorta at L2.
Are the epididymis and testis fully surrounded by tunica vaginalis?
No, the tunica vaginals covers only the anterior and lateral aspects of the testis and epididymis; their posterior aspect is attached to the posterior wall of the scrotum.
What is the ‘appendix of the testis’ a remnant of?
The paramesonephric duct
Describe the nerve supply of Scrotal skin
Supplied anteriorly by L1 fibres (ilioinguinal), posteriorly by S3, 4 fibres (pudendal)
What stimulates the seminal vesicles?
Testosterone
What stores spermatozoa prior to emission?
Vas deferens
Transition zone of the prostate
Anterolateral to the proximal urethra, benign hyperplasia often occurs here
Peripheral zone of the prostate
Surrounds the more distal urethra accounting for ~70% of volume - cancer commonly occurs here
Nerve supply of testis, vas deferens and epididymis
Sympathetic T1-L1
Nerve supply of the outer testis, tunica vaginalis and anterior scrotum
Somatic L1-L2 genitofemoral (Cremaster) and ilioinguinal
Nerve supply of the rest of the scrotum
S2-S3 somatic
Where does congenital hydrocele gather?
Between the pareital and visceral layers of tunica vaginalis
What is a varicoele?
Abnormal dilation of testicular veins of pampiniform plexus
What side is a testicular varicoele more common on and why?
Left due to the angle at which the left testicular vein drains into the left renal vein and lack of valves
Testicular torsion cause
Spermatic cord twists within the tunica vaginalis
Normal descent of testes timing
28 weeks reach inguinal canals, 28-40 weeks they descend to scrotum
Vasectomy process
Ligation of vas deferens
