Male Reproductive Tracts Flashcards
Tunica albuginea
A thick, dense collagenous capsule enclosing the testis
What divides the testis into lobules
Fibrous septa
Number of lobules in testis
250
What does each testicular lobule contain
Up to 4 germ-cell producing seminiferous tubules
Seminiferous tubule
A 50cm loop
Open at both ends
Rete testis
A network of channels that collect sperm from the seminiferous tubules and deliver it to the epididymis
What do seminiferous tubules drain into
Rete testis
Length of seminiferous epithelium in 2 testes
1km
Leydig cells
Produce testosterone
Where are leydig cells located
In clumps between the loops of seminiferous tubules
What lines the seminiferous tubules
Stratified epithelium consisting of supporting Sertoli cells and cells of the germ line (developing spermatozoa)
Cells at the peripheral of each seminiferous tubule
Spermatogonia
Structure of spermatogonia
germinal epithelium that produces large cells with speckled chromatin within their nuclei
Where do spermatocytes develop from
Spermatogonia
Function of Sertoli cells
Form blood-testis barrier
Nurture the developing sperm
How long does sperm production take
64 days
Wave of maturation
Sperm maturation
Passes slowly down each tubule
Consequence of failure of the blood-testis barrier
Individual would recognise sperm as non-self and raise antibodies against them
Destroy sperm rendering him infertile
How to recognise Sertoli cells
Pale-staining irregular nucleus
What encloses each seminiferous tubule
A thin fibrous collagenous capsule
Cells towards the centre of the seminiferous tubule
Depends on phase of spermatogenesis cycle
How to recognise primary and secondary spermatocytes or spermatids
Small dense round nucleus
How to recognise spermatozoa
Narrow elongated nuclei- heads
At what stage of development of sperm does reduction division take place
First meiotic division occurs when the primary spermatocytes become secondary spermatocytes
Where does the reduction division take place in relation to the blood-testis barrier
Occurs on luminal side of barrier where the developing spermatids are not in direct contact with the blood stream - prevents production of auto-antibodies that would destroy the sperm
What lines the Rete testis
Cuboidal epithelium
Structure of epididymis
Single long (5cm) coiled tube surrounded by a thick fibrous capsule
Attachment of epididymis
Mediastinum of testis posteirorlj
Length of epididymis
5cm
Function of epididymis
Storage and maturation site for sperm
What lines the epididymis
Tall pseudo-stratified columnar epithelium
Small rounded basal cells support tall columnar cells with stereocilia (very long microvilli)
Function of columnar cells with stereocilia in epididymis
Re-absorb excess testicular fluid
Phagocytose damaged sperm and cell debris
Provide nutrients for waiting sperm
What surrounds the epididymis
A thin layer of smooth muscle which becomes thicker and multi-layered as it approaches the vas deferens
What is unique about stereocilia
Not motile and do not have a core of microtubules- unlike cilia
Structure of vas deferens
Spirally arranged layers of smooth muscle
Lining of vas deferens
Pseudo-stratified columnar epithelium (less tall than epididymis)
Small rounded basal cells supporting columnar cells with microvilli (shorter than epididymis)
Sometimes thrown into longitudinal folds supported by a laminated propria
What helps to expel sperm during ejaculation
Sudden and rhythmic contractions of the vas deferens