Male Anatomy Flashcards
Both sexes develop from a different embryological primordium and form similar internal genitalia. True or False?
False. Both sexes develop from a common embryological primordium which forms separately to the internal genitalia.
In what manner do indifferent gonads develop?
Retroperitoneally
Where do indifferent gonads develop?
- High on the posterior body wall
2. Medial to the embryonic kidney or mesonephros
What takes over after the gradual degeneration of mesonephros?
Permanent kidneys or metanephros
What are some of the mesonephric ducts recycled as?
Male internal genitalia
How do female internal genitalia develop?
From a separate set of ducts, the paramesonephric ducts.
What is responsible for testis differentiation during week 6 of development?
Under the influence of a gene on the Y chromosome, the TESTIS DETERMINING FACTOR.
Ovaries develop earlier than testes. True or false?
False. Ovaries develop later.
When does the gubernaculum start to form?
As the mesonephros degenerate in week 8
What is the gubernaculum?
Strand of connective tissue on either side of the vertebral column.
Where does the gubernaculum extend?
From the INFERIOR POLE OF OVARY OR TESTIS through muscle of the ABDOMINAL WALL and into LABIOSCROTAL FOLD.
What does the transition of the gubernaculum through the abdominal wall become in the future?
Inguinal canal
When does the testis enlarge?
When the mesonephros degenerate
Where has the testis moved about 25 weeks later?
From the abdomen into the pelvis.
What happens during the outfolding of the peritoneum?
The processus vaginalis forms anterior to each gubernaculum.
Where does the processus vaginalis grow down into?
The scrotum with the tesits.
The final descent of testes into scrotum is slow. True or false.
False, it is quick.
What occurs once the testes have descended?
The processus vaginalis closes.
Direct connection with peritoneal cavity is lost.
Is the processus vaginalis fully closed?
No. There is a small cavity in front of the testis.
What is the inguinal canal lined with?
Connective tissue
What structures does the inguinal canal contain?
Structure which descended with the testis: ductus deferens, blood vessels, nerves, lymph vessels.
What is the function of the distal end of the gubernaculum?
Small structure anchoring testis to scrotum.
What does the opening in the transversalis fascia become?
Deep inguinal ring
What does the external oblique become?
Superficial ring
The gubernaculum shortens during some stages of descent. True or false.
False. It shortens during all stages of descent.
In females what does the developing gubernaculum become attached to?
Sides of the structures which will form the uterus.
In which directions does the ovaries descend into the pelvis?
They move laterally.
The female gubernaculum does not shorten. True or false?
True.
What does the female gubernaculum become incoportaed into?
The broad ligament as the ovarian ligament and round ligament.
Where does the round ligament run?
From the uterotubuluar junction to the side wall of the pelvis and the deep inguinal ring.
What does the round ligament pass through?
Passes through the inguinal canal and superficial ring to end in mons or labium majora.
What is the scrotum comprised of?
Skin, with cutaneous dartos muscle
Which layer is the scrotum a part of?
Superficial fascia
What is the function of the scrotum?
Muscle controls loss of heat by wrinkling the skin (temperature is important for sperm production)
What is the testes comprised of?
Oval, each covered with dense connective tissue, the tunica albuginea.
What does the tunica albuginea form?
The tunica albuginea thickens posteriorly to form the mediastinum testis
What does the mediastinum testis contain?
Contains ducts connecting seminiferous tubules with epididymus.
What do the anterior, medial and lateral testis face?
A serous cavity dervied from the processus vaginalism
What lines the testes?
Tunica vaginalis
What do the testis contain?
Seminferous tubules with spermatogenic cells and Sertoli cells and Leydig cells - testosterone production.
What is the epididymus?
A single tightly coiled tube
Where does the epididymus lie?
On the superior and posterolateral sides of the testis - continuous with ductus deferens.
Where is the head and tail of the epididymys?
It is adherent to testis.
Where is the body of the epididymus?
Separated from testis by sinus of epididymus
What is the function of the epididymus?
Absorbs testicular fluid, phagocytoses dead sperm, maturation of normal sperm.
Where does the spermatic cord extend from?
Extends from deep inguinal ring to superior pole of testis.
What does the spermatic cord contain?
- Ductus deferens
- Arteries of testis and ductus deferens
- Cremasteric artery
- Pampiniform plexus of veins
- Lymph vessels draining testis but not scrotum
- Nerves (as a plexus on arteries) including sympathetic and parasympathetic fibres from inferior hypogastric plexus
What is the cremasteric artery a branch of and what does it anastomose with?
Branch of the inferior epigastric artery
Anastomoses with testicular artery (near testis)
What does the pampiniform plexus of veins join to form?
3-4 veins in the inguinal canal
Then join to become 2 veins after deep inguinal ring.
What is the spermatic cord covered with? Why?
Cremasteric muscle - elevate testis.
What vessels does the blood supply to the testis and epididymus?
Testicular arteries
Testicular veins
Cremasteric artery
Where are the testicular arteries?
Off aorta just below renal arteries - cross psoas major with ureters.
Where are the testicular veins?
Right into inferior vena cava, left into left renal vein.
What is the ductus deferens?
30-45 cm long with thick muscular wall.
Where does the ductus deferens extend?
- Extends from tail of epididymus, through spermatic cord.
- At deep inguinal ring it leaves the spermatic cord and passes medially over external iliac vessels onto lateral wall of pelvis.
- Crosses superior to ureter at base of bladder where it expands to from a dilation, the ampulla
- Joined by duct of seminal vesicle to form ejaculatory duct
Where is sperm stored?
Ampulla
What are the seminal vesicles?
Paired structures between base of bladder and rectum
What do the seminal vesicles consist of?
Single tubes 15 cm long coiled down to 5 cm