Session 1 - The Male Reproductive System Flashcards
What are the functions of the penis?
Sexual intercourse - erection, ejaculation, remission
Micturation - contains the urethra, expels urine from the body
The penis ca be anatomically divided into what three parts?
Root - proximal, fixed part of the penis. Not visible externally.
Body - free part of the penis,suspended from pubic symphysis.
Glans - distal, has external urethral orifice
The glans is a distal expansion of what?
The corpus spongiosum
What three cylinders of erectile tissue are found in the penis?
Two corpus cavernosa
Corpus spongiosum
What are the corpora cavernosa and the corpus spongiosum called in the root of the penis?
Left and right crura (corpora cavernosa)
Bulb (corpus spongiosum)
During erection, why does the corpus spongiosum fill to a reduce pressure compared to the corpus cavernosa?
To prevent the urethra becoming occluded during erection.
What are the four muscles located in the root of the penis?
Bulbospongiosus (x2)
Ischiocavernosus (x2)
The root of the penis is supported by what two ligaments?
Suspensory ligament
Fundiform ligament
Each mass of erectile tissue has what two fascia coverings?
Deep fascia of the penis (continuation of deep perineal fascia). Binds erectile tissues together.
Tunica albuginea, forms an individual capsule around each cavernous body.
What is the prepuce?
Foreskin. Double layer of skin and fascia, located at the neck of the glans. It covers the glans to a variable extent.
What connects the prepuce to the skin of the glans?
Frenulum (a median fold of skin on the ventral surface of the penis).
What is the preputial sac?
The potential space between the glans and prepuce
What arteries supply the penis? These are all branches of what artery?
Dorsal arteries of the penis
Deep arteries of the penis
Bulbourethral artery
These are all branches of the internal pudendal artery.
What vessel does the internal pudendal artery arise from?
Internal iliac artery
Venous blood drains from the penis through what two veins?
Deep dorsal vein of the penis (drains cavernous spaces). Empties into prostatic venous plexus.
Superficial dorsal veins (drains superficial structures, e.g. skin and cutaneous tissue).
Sensory and sympathetic innervation of the skin and glans penis is supplied by what nerve?
Dorsal nerve of the penis, a branch of the pudendal nerve.
Parasympathetic innervation of the penis is supplied by what nerves?
Carried by cavernous nerves from the prostatic nerve plexus
What is hypospadia?
A congenital condition in which patients are born with the opening to their urethra on the ventral aspect of the penis. Can be corrected with surgery.
What is phimosis?
A condition where the prepuce fits tightly over the glans and cannot be retracted. It an cause irritation when smegma (oily secretions) accumulate in the preputial sac.
What is paraphimosis?
A more severe variant of phimosis, where retraction of the prepuce constricts the neck of the glans, interfering with venous and lympathic drainage. This may cause the glans to enlarge to the extent that the prepuce cannot be drawn over it.
What is Peyronie’s disease?
An abnormal curvature of the shaft of the penis caused by a build up of scar tissue. May cause pain on erection. Surgical correction needed in severe cases.
What is erectile dysfunction?
The inability to maintain an erection
What are the causes of erectile dysfunction?
Most commonly due to vascular aetiology - hypertension, hypercholesterolaemia or diabetes. Possible psychological causes include anxiety and depression.
What is priapism?
An erection that persists for more than four hours despite a lack of sexual stimulation. It is often painful and results from blood becoming trapped in the erectile bodies. If untreated may lead to scarring and erectile dysfunction.
Where in the testes does spermatogenesis occur?
Seminiferous tubules
What is the function of the testes?
Site of sperm production and hormone synthesis.
What is the function of the epididymis?
Storage of sperm
Where is the epididymis located in relation to the testes?
On the posterolateral aspect of each testicle.
The testes are suspended from the abdomen by what?
The spermatic cord
What is the spermatic cord?
Collection of vessels, nerves and ducts that supply the testes.
What are the three parts of the epididymis?
Head - proximal, formed by the efferent tubules of the testes
Body - heavily coiled duct of the epididymis
Tail - distal, marks the origin of the vas deferens
What is the function of the vas deferens?
Transports sperm from the epididymis to the urethra
What is the testicular plexus?
A network of nerves derived from the renal and aortic plexi. Supply autonomic and sensory fibres to the testes and epididymis.
What are the most common causes of scrotal swelling?
Inguinal hernia Hydrocoeles Haematocoele Varicocoele Epididymitis
What is a hydrocoele?
A collection of serous fluid within the tunica vaginalis. It is most common due to a failure of the processus vaginalis to close.
What is a haematocoele?
A collection of blood in the tunica vaginalis.
How can a hydrocoele be distinguished from a haematocoele?
Transillumination (shine a light through the testicular swelling). Due to the dense nature of blood light is unable to pas through a haematocoele, but will be able to pass through a hydrocoele.
What is a varicocoele?
A gross dilation of the veins draining the testes. The left testicle is more commonly affected. A large varicocoele can look and feel like a bag of worms within the scrotum.
What is epididymitis?
Inflammation of the epididymis, usually caused by bacterial or viral infection.
What is testicular torsion?
When the testicle rotates, twisting the spermatic cord and possibly occluding the testicular artery. Causes sudden severe pain and swelling.
Why can the testicles not swap sides?
Septum of the scrotum
How does the spermatic fascia come to surround the testis and its vessels?
During development, the testes evaginate the abdominal wall as they are pulled through by the gubernaculum, forming the spermatic fascia that surrounds the testis and its vessels.
What three major (paired) structures are contained in scrotum?
Testis - the site of spermatids production
Epididymis - situated at the head of each testicle, it functions as a storage reservoir for sperm
Spermatic cord - a collection of muscle fibres, vessels, nerves and ducts that run to and from the testes
What is the function of the darts muscle in the scrotum?
Regulates the temperature of the scrotum by wrinkling the skin - this decreases surface area decreasing heat loss.
What is the spermatic cord?
A collection of vessels, nerves and ducts that run to and from the testes.
Describe the anatomical course of the spermatic cord.
Spermatic cord starts at the the deep inguinal ring, passes through the inguinal canal and enters the scrotum via the superficial inguinal ring. It continues into the scrotum, ending at the posterior border of the testes.
What are the three fascia layers of the spermatic cord?
External spermatic fascia
Cremasteric fascia
Internal spermatic fascia
What arteries are found in the spermatic cord?
Testicular artery
Artery to the vas deferens
Cremasteric artery
What veins are found in the spermatic cord?
Testicular vein (pampiniform plexus) Vein from the vas deferens Cremasteric vein
What nerves are found in the spermatic cord?
Ilioinguinal nerve
Genital branch of genitofemoral nerve (nerve to cremaster muscle)
Autonomic nerves
What is pampiniform plexus?
A network of veins responsible for the venous drainage of the testes. Wraps around the testicular artery. Acts as heat exchanger, cooling the arterial blood before it reaches the testes.
How can a diagnosis of testicular torsion be confirmed?
Ultrasound
Colour Doppler scanning
What is the prostate? What is its function?
The prostate is the largest accessory gland i the male reproductive system. It secretes proteolytic enzymes into the semen, which act to break down clotting factors in the ejaculate. This allows the semen to remain in the fluid state.
Where is the prostate located?
Inferior to the neck of the bladder and superior to the external urethral sphincter. Anterior to the ampulla of the rectum.
The anatomical relation of the rectum to the prostate is significant for what examination?
Digital Rectal Examinations (DRE). Ampulla of the rectum lies posteriorly to the prostate gland, allows the prostate to be examined by DRE.
What are the three zones of the prostate?
Central zone - surrounds the ejaculatory ducts
Transitional zone - located centrally and surrounds the urethra
Peripheral zone - makes up main body of the gland and is located posteriorly
What are the embryological derivatives of the different zones of the prostate?
Central zone - derived from the Wolffian duct
Transitional zone - derived from the urogenital sinus
Peripheral zone - derived from the urogenital sinus
Benign prostatic hyperplasia typically affects what zone of the prostate?
Transitional zone
Prostate cancers typically affect what zone of the prostate?
Peripheral zone
What is Benign Prostatic Hyperplasia (BPH)?
Increase in size of the prostate without the presence of malignancy. Much more common with advancing age.
How will men with Benign Prostatic Hyperplasia present and why?
The enlarging prostate compresses on both the bladder and the urethra, resulting in urinary frequency, urinary urgency and difficulty in initiating micturition.
Where is the origin of the testicular arteries?
Abdominal aorta
Describe the venous drainage of the right and left testis.
Testicular veins form from the pampiniform plexus. Left testicular vein drains into the left renal vein. Right testicular vein drains directly into the inferior vena cava.
What is the difference in lymphatic drainage of the scrotum compared to the testes?
Lymphatic drainage of the testis goes to the paired lumbar and para-aortic nodes, located at L1 vertebral level. This is in contrast to the scrotum, which drains into nearby superficial inguinal nodes.
What is the cremasteric reflex?
Reflex where stroking in superior and medial part of the thigh produces an immediate contraction of the cremaster muscle. This elevates the testis on the side that has been stimulated.
What are the afferent and efferent limbs of the cremasteric reflex?
Afferent (sensory) limb - ilioinguinal or genitofemoral nerve
Efferent (motor) limb - genital branch of the genitofemoral nerve
From which layers of the abdominal wall are the fascia coverings of the spermatic cord derived?
External spermatic fascia - derived from the aponeurosis of the external oblique
Cremasteric muscle and fascia - derived from the internal oblique
Internal spermatic fascia - derived from transversalis fascia
List the accessory glands of the male reproductive system.
Prostate gland
Seminal vesicles
Bulbourethral glands
Identify the substances secreted by the accessory glands of the male reproductive system.
Prostate gland - proteolytic enzymes
Seminal vesicles - alkaline fluid, fructose, prostaglandins, clotting factors
Bulbourethral gland - mucus
Which part of the prostate gland is felt on rectal examination?
Peripheral zone
Which part of the urethra is least distensible?
Membranous urethra
Why is a varicocoele almost always in the left testis?
The left testicular vein drains into a smaller vessel, the left renal vein, at a perpendicular angle.
