Male Anatomy Flashcards
Name the six layers of the scrotum
Tunica Albuginea (consists of collagen, connective tissue and smooth muscle) Visceral vaginal tunic Parietal vaginal tunic Scrotal fascia Tunica dartos Scrotal skin (contains sweat glands)
What is the role of the tunica dartos?
It adjusts the height of the testes in response to temperature by long term contraction via androgen control.
What role does the scrotal skin play in temperature control?
The skin is innervated by sympathetic nerves which feed back to the hypothalamus, if there is an increase in temperature the hypothalamus will trigger the sweat glands
What is the mediastinum?
The central connective tissue core of the testes
Where are sperm produced?
In the seminiferous tubules, as they mature they move fro the outside to the inside of the tubes
What cells lie on the basement membrane of the seminiferous tubules?
Sertoli cells, they support the germ cells as they mature
What is the path of the sperm as they mature
The sperm starts in the seminiferous tubles which consists of the convoluted tuble (where the spermatozoa are produced) and then the straight tubule. From here the sperm move to the rete tubules (in the mediastinum) and then to the efferent ducts which connect to the head of the epididymis
Describe the ultrasound appearance of the testes
Mediastinum is central and bright white (hyper echoic)
What is the epididymis?
Is one large (30-60m) convoluted duct that consists of the head (caput), body (corpus), tail (cauda)
It is surrounded by smooth muscle that contracts rhythmically and aids the transport of spermatozoa
The main functions of the epididymis is for the reabsorption of fluid and the secretion of proteins
What is the epididymis transit time?
The time taken for the spermatozoa to travel from the proximal head to the distal tail of the epididymis
What is the function of the ductus deferens?
Connects the epididymis tail to the pelvic urethra
Has a very strong muscular wall for the propulsion of spermatozoa
What is the spermatic cord made up of?
Consists of the ductus deferens, testicular artery and vein (pampiniform plexus), and cremaster muscle
Where does the testicular artery come from and how does it form the pampiniform plexus?
The testicular artery comes from the abdominal aorta and once it passes through the inguinal canal it becomes very convoluted and is surrounded by veins and this is the pampiniform plexus.
What is the function of the pampiniform plexus?
The pampiniform plexus acts as a heat exchanger, pulse pressure eliminator and allows transfer of testosterone from the testicular vein to the artery so maintaining the high level of testosterone in the testis.
What is the function of the cremaster muscle?
The cremaster muscle is striated and acts for short term elevation of the testes.
Name all the possible accessory sex glands?
Ampulla of the deferent duct, vesicular gland, prostate gland (corpus prostate sits above urethra and disseminate prostate sits in the wall of the urethra) and the bulbourethral gland.
What accessory sex glands do stallions have?
Ampulla of the deferent duct, vesicular gland, prostate gland (lacks desseminate part) and the bulbourethral gland.
The stallion has colliculus seminalis, a common duct of the ampulla and vesicular gland. Is the opening of the ejaculatory ducts.
What accessory sex glands do boar have?
The boar lacks ampulla however other glands are very large so there is a large volume of ejaculate
What accessory sex glands do dogs have?
Dog – only has the ampulla and corpus prostate, which is bilobed
What accessory sex glands do bulls have?
Bull – all glands present but a very small prostate corpus which means a small volume of ejaculate
See table of glands
What is the function of seminal plasma?
Needed for the dilution and delivery of sperm, it also contains fructose as an energy source in all species except the stallion.
In the sow the seminal plasma coagulates and blocks the cervix thus preventing reflux of semen
Name the muscles surrounding the urethra
Urethral muscle – surrounding the pelvic urethra
Bulbospongious muscle – surrounds the bulbourethral glands and the penile urethra
Both are striated muscles important for the transport of semen through the urethra
What three regions does the penis consist of?
Consists of the root (with paired crura attached to the ischiatic arch), the shaft (corpus) and the glans.
Where does the blood supply to the accessory glands and the penis come from?
The blood supply to the accessory glands and penis come from the internal pudendal artery (terminal branch of the internal iliac artery)
