The male reproductive system Flashcards
What divides the scrotum internally and externally?
Internally - Scrotal septum
Externally- Raphe
What is contained in the scrotum?
Deeply pigmented skin, fibrous tissue and muscle
What muscle is contained in the scrotum?
The dartos muscle (smooth muscle) and the cremaster muscle (a continuation of the internal obliques of the abdominal wall)
What is the function of the scrotal muscles?
Controlling the position and therefore temperature of the testes
What produces sperm?
The testes
Where do the testes begin development?
They are formed just below the kidneys, gradually descending through the inguinal canal
What is the structure of the testes?
Serous outside membrane - tunica vaginalis
Tough fibrous inner layer - tunica albuginea, this extends in forming septa that separate the testes into 200-300 lobules
Each lobule contains long coiled tubules called seminiferous tubules
What types of cells are contained in the seminiferous tubules of the testes and what are their functions?
Spermatogenic cells - form sperm
Sertoli cells - support the spermatogenic cells
What are Leydig cells?
The interstitial cells of the testes located between adjacent seminiferous tubules
What is the function of Leydig cells?
Testosterone production
What is spermatogenesis?
Sperm production
When does spermatogenesis begin?
Puberty, with 300 million produced each day
How long does it take a single sperm to develop?
10 weeks
What is the structure of a sperm?
Acrosome
Flattened pointed head
Neck
Tail: middle, principle and end pieces
What is the sperm acrosome?
A cap like sac covering the head of the sperm filled with enzymes that help the sperm penetrate the ovum
Where does the sperm get energy for its activity?
Mitochondria in the middle piece of the tail
What is contained in the sperm head?
A nucleus containing 23 chromosomes
How long do sperm survive without the female reproductive system?
Around 48 hours
What environment do sperm need to survive?
Alkaline
What is contained in semen?
Sperm and seminal fluid
What is seminal fluid?
A thick whitish fluid consisting of fluids secreted by the seminiferous tubules, seminal vesicles, prostate gland and bulbo-urethral glands
Where is the prostate located?
At the base of the bladder, surrounding the urethra
What are bulbo-urethral glands?
A pair of pea sized glands situated either side of the urethra
What is the purpose of the bulbo-urethral glands?
They produce a few drops of fluid upon arousal which act as a lubricant and neutralises the acidity of the urethra
What are the seminal vesicles?
A pair of glands close to the prostate, either side of the bladder
What do seminal vesicles do?
Produce seminal fluid which makes up around 60% of semen volume, it is fluid that provides nourishment and fuel for the sperm and aids their movement
What is the order of the ducts the sperm passes through from the testes to outside the body?
Epididymis
Ductus (vas) deferens
Ejaculatory duct
Urethra
What is the epididymis?
A coiled single tube, acting as a reservoir of sperms on their exit from the testes.
What are the ductus deferens?
Thick wall muscular tubes that transport the sperm from the epididymis to the ejaculatory duct
What is the ejaculatory duct?
The duct formed from the ductus deferens as it passes over the top and down the posterior surface of the bladder
The ejaculatory duct passes through the prostate to open into the urethra
What is the structure of the shaft of the penis?
3 parallel cylindrical masses of tissue covered by a fibrous tunica albuginea
What are the masses of the penis shaft called?
Two dorsal: corpus cavernosa penis
One ventral: corpus spongiosum penis
