1. The Male Reproductive System Flashcards
What are 7 parts that the male reproductive system can be split into?
- penis
- testes and epididymis
- scrotum
- spermatic cord
- prostate gland
- bulbourethral glands
- seminal vesicles
Where are the testis found?
testes are suspended in the scrotum by the spermatic cords
Where are the male reproductive system found?
- the male reproductive system usually resides within the pelvis
- some tissues sit outside of the pelvis in the scrotum
Why are the testis found externally?
to allow spermatogenesis to occur at the optimum temperature, which is slightly cooler than core body temperature.
Which artery supplies the testes and where does it originate from?
Testicular artery which originates directly from the abdominal aorta, below renal arteries
What is the venous drainage of the testes and describe its structure?
Pampiniform plexus which surrounds the artery, they form the right and left testicular veins.
Where do the right and left testicular veins drain?
Right drains directly into the IVC, left drains into the left renal vein
What is the effect of the pampiniform plexus?
is thought to cool blood arriving to the testes further - heat from arteries transferred to cooler veins
Which veins are dilated in varicocoele and what does it feel like upon palpitaion?
Testicular veins in the pampiniform plexus, feels like a bag of worms
Which side is varicocoele more common in and why?
Left:
- angle of which left testicular vein enters left renal vein. - horizontally - gravity - pooling of blood
- lack of effective valves between testicular and renal veins
- increased reflux from compression of renal vein
What causes varicocoele?
If pampiniform plexus obstructed, for example due to renal or intra-abdominal pathology, this can enlarge leading to a varicocoele.
Where is the lymphatic drainage of the scrotum and testes to?
Scrotum: superficial/deep inguinal lymph nodes
testes: para-aortic lymph nodes
How do the testes descend into the scrotum?
They evaginate the abdominal wall as they are pulled through by the gubernaculum, forming spermatic fascia that surrounds the testis and its vessels
How is the inguinal canal formed?
In order to descend, the testes took layers of the abdominal wall to form the inguinal canal, a common point of hernias
Hows does the peritoneum form around the testis?
When descending from the abdominal cavity during development, the testis also took the peritoneum
with them, which envelopes the testes as the tunica vaginalis
What does the gubernalculum do?
connects scrotum to inferior aspect of testis and guides testis down through abdominal wall
What forms the spermatic fascia that surrounds the testes?
The layers of the abdominal wall form the spermatic fascia which becomes the wall of the spermatic cord
What are the different layers of the spermatic cord and what are they formed from?
- External spermatic fascia formed from external oblique muscle.
- Cremasteric fascia/muscle from the internal oblique muscle.
- Internal spermatic fascia from the trasnversalis fascia.
What is the rule of 3s?
Spermatic cord contains 3 arteries, 3 veins, 3 nerves (and vas deferens)
Where are the arteries/veins of within the spermatic cord form?
- Testicular artery and artery to vas deferens deep to the internal spermatic fascia.
- Cremasteric artery to cremaster muscle between inner 2 layers.
- Veins with the corresponding artery
Where are the nerves of within the spermatic cord form?
- Sympathetics to vas deep to internal spermatic fascia.
- Genital branch of the genitofemoral nerve (cremasteric nerve)between outer 2 layers.
- Ilioinguinal nerve outside the external spermatic fascia.
What is the function of the cremaster muscle and what is it innervated by?
Regulates height of the testes in the scrotum to maintain right temperature for spermiation. Innervated by genital branch of the genitofemoral nerve
What is the cremasteric reflex?
Elevation of the testicle after stroking the inner thigh
What condition causes the cremasteric reflex to be absent?
torsion of the testicle
What structure directly supports the internal structures of the testes?
Tunica albuginea (capsule)
What is hydroceoele?
Abnormal collection of fluid within the cavity of tunica vaginalis.
What are seminiferous tubules?
key functional units found within compartments in the testis where spermatogenesis occurs
Which cells form the seminiferous tubules and what are they responsible for?
two distinct populations of cells,
- spermatogenic cells, that develop into spermatozoa,
- Sertoli cells which have a supportive and nutrient function. - support developing sperm by pruning away cytoplasm to make them more streamlined
What type of cells are found in the extracellular tissue of the seminiferous tubules and what are they responsible for?
Leydig cells, produce sex hormones - testeosterone
What organelle is in high numbers in leydig cells?
SER - active in lipid metabolism
cholesterol -> testosterone
describe the structures that the seminiferous tubules drain into
SEMINFEROUS TUBULES drain intoRETE TESTIS which drains into EFFERENT DUCTULES which drains into (head of the) EPIDIDYMIS which drains into ductus/vas deferens
What occurs in the epididymis?
sperm maturation
What are the layers of the tunica vaginalis?
Parietal
cavity
visceral
How is a scrotal swelling assessed to see if it is a hydroceoele?
Shine a light through the swelling - transillumination
if hydroceoele, light will pass through
which testes is suspended more inferiorly?
left
What separates the seminiferous tubules into compartments?
connective tissue continues with the tunica albuginea
Where does the vas deferens travel and what does it join onto? Describe its relation to the ureters.
Travels through the spermatic cord and goes into the abdomen where it joins with the ejaculatory duct. Intraabdominally the ureters travel underneath the vas deferens
What does the vas deferens join with to form the ejaculatory duct and what is its function?
duct of Seminal vesicles, contributes to 65% of the ejaculate as a fructose based alkaline fluid. Provides nutrition for sperm and neutralises acific environment of vagina.
Which part of the prostate does the ejactulatory duct and the urethra pass through?
ejaculatory duct passes through central zone, uretha passes through transition zone
Which part of the prostate does BPH and prostate cancer tend to affect?
BPH tends to affect transtional zone (urethra)
Cancer tends to affect peripheral zone
How much does the prostate contribute to the ejaculatory fluid and what does it contain?
25%, contains proteolytic enzymes, zinc (motility) and is mildly acidic.
How much does the bulbourethral gland contribute to the ejaculatory fluid and what is its purpose?
Approx. 1%, contains mucoproteins which reduces friction and neutralises acidic urine in distal urethra.
Where are the bulbourethral glands found?
posterolateral to the membranous urethra; ducts open into the spongy urethra
Where does the vas deferens and seminal vesicles join to for the ejaculatory duct?
prostate gland
What are the names of the urethra as it passes through each structure
pre prostatic urethra –> prostatic urethra –> membranous urethra –> spongy urethra
what are the relations of the vas deferens to ureter and uterine artery in males and females?
water under the bridge
- in males ureter passes under vas
- in females uterine artery passes under vas
which structure contributes the majority of the ejaculatory fluid?
Seminal vesicle - 65%
Why is it difficult to catheterise a male?
bends in urethra - 2
- straighten penis to straighten first bend
- apply pressure and slightly pull down to straighten second bend
What are the 2 different types of tissue that comprises the penis and which is the main erectile tissue?
Corpus spongiosum and corpus cavernosum (main erectile tissue)
what is the function of the penis?
– Expulsion of urine via urethra
– Deposition of sperm in female genital tract – Removal of competitors’ sperm?
– Attraction of mates?
Where is the tunica albuginea of the penis found and what is its function?
Found surrounding each of the corpus cavernosa and the corpus spongiosum. Required to give support to the penis during erection.
which tissue of the penis is the urethra found?
The corpus spongiosum is the expansile tissue through which the urethra travels. It stays patent for the passage of sperm during ejaculation.
What is the organisation of collagen fibres in the tunica albuginea of the penis?
Arrganged at right angles to each other, one circumferential and one parallel to the penile long axis
What is the blood supply to the penis?
Branches of the internal pudendal vessels which is a branch of the internal iliac artery
What is testicular torsion?
Twisting of the spermatic cord resulting occlusion of venous drainage which increases capillary pressure and compresses arteries resulting in loss of blood supply and nerve function to the testicle.
Why is testicular torsion a medical emergency?
Blood supply occluded, could lead to infarction and death of the testis. Subsequent atrophy, infection and cosmetic deformity
Which part of the prostate is readily palpable during a DRE?
Peripheral zone
Enlargement of which part of the prostate causes urethral obstruction?
Transitional zone
How does erection occur and what part of the nervous system is responsible foe this?
Vasodilation of penile arterioles and compression of veins. Initiated by parasympathetic stimulation which inhibits sympathetics
What causes erection to terminate and what part of the nervous system is responsible for this?
Vasoconstriction, by sympathetic system.
What part of the nervous system is responsible for ejaculation?
Primarily the sympathetic
Point and Shoot
how is the penis anchored to bone
via the suspensory ligaments
corpus cavernous are attached to bone to help anchor the penis.
what is the dartos muscle?
Thedartosmuscle is a sheet of smooth muscle, situated immediately underneath the skin of the scrotum. It acts to help regulate the temperature of the scrotum.
what is the blood supply to the scrotum?
The scrotumreceivesarterial supply from theanteriorandposterior scrotal arteries. The anterior scrotal artery arises from the external pudendal artery, while the posterior is derived from the internal pudendal artery.
what are the veins of the scrotum?
Thescrotal veinsfollow the major arteries, draining into the external pudendal veins.
what is epididymitis?
inflammation of the epididymis, usually caused by bacterial or viral infection
what is varicocele?
gross dilation of the veins draining the testes
what is Haematocoele
a collection of blood in the tunica vaginalis.
what is Inguinal hernia
where the contents of the abdominal cavity protrude into the scrotum
Which anatomical space does the spermatic cord travel through?
inguinal canal
what do the contents released by seminal vesicle contain and what is their function?
Alkaline fluid - neutralises the acidity of the male urethra and vagina in order to facilitate the survival of spermatozoa.
Fructose- provides an energy source for spermatozoa.
Prostaglandins - have a role in suppressing the female immune response to foreign semen
Clotting factors- designed to keep semen in the female reproductive tract post-ejaculation
what is the main role of prostate?
produce proteolytic enzymes
what is the function of bulbourethral glands?
During sexual arousal, the bulbourethral glands produce a mucus secretion containingglycoproteins. This substance has three main purposes:
Serves as lubrication medium for the urethra and the tip of the penis.
Expels any residue of urine, dead cells or mucous through the urethral meatus, preparing a clean and lubricated pathway for ejaculation.
Helps to neutralise residual acidity in the male urethra (secretions are alkaline).
what part of the urethra do the bulbourethral glands drain into?
spongy
