Male Reproductive Histology Flashcards
(40 cards)
What produces sperm and androgen?
Testes
What transports sperm?
epididymis, ductus deferens, ejaculatory duct, urethra
semen production and sperm nutrient source?
seminal vesicle
prostate gland
bulbourethral glands
Testes?
1) responsible for what?
2) where are they located and what holds them there
3) closely associated with what
4) what is it surrounded by, include both layers
5) what can we find inside the testicle itself?
responsible for producing sperm
located in the scrotum which is important for keeping the sperm at an appropriate temperature
it’s closely associated with the epididymis.
it’s surrounded by the tunica albuginea (dense CT capsule)
deep to this in the actual testes are seminiferous tubules, which is where sperm production is going to take place
more superficial to the tunica albuginia is the tunica vaginalis (derived from the peritoneum)
more posteriorly the connective tissue organization changes into the “Rete testis”.. which is part of the way sperm can leave the testes and be transported to the epididymis
Seminiferous Tubules?
how many are there?
what is within each tubule?
what do both of these cells make up?
What surrounds the seminiferous tubules and what do they do?
highly convoluted and one tube in each lobule.
within each tubule you’ll see Somatic Sertoli cells, and Spermatogenic cells
organization of sertoli and spermatogenic make up the seminiferous epithelium.
these tubules are surrounded by peritubular myoid cells.. these are contractile that propel spermatazoa out of the tubules to the rete testis.
What’s found between the seminiferous tubules?
Interstitial cells of Leydig
What do Sertoli cells have?
hallmark?
what can be seen going from Sertoli cell to Sertoli cell?
they have these cytoplasmic pockets that the developing sperm that will embed themselves in, and that helps to aide in sperm development and the changes they undergo as they go from beginning form to sperm.
have a very large nucleus, and in the middle is a “cyclops nucleus”
they make junctional complexes to each other.
what is the sertoli-sertoli complex?
what do they create?
what happens to someone f the developing spermatogonia?
significant amount of tight junctions that are established between Sertoli cells to create a barrier from the basal surface of the epithelium and to separate that from the luminal surface.
so separates the basal and luminal compartment.
some of the developing spermatogonia remain in the basal compartment and be shifted to the luminal compartment
why is the sertoli-sertoli complex important?
what cell type is isolated from systemic circulation?
this creates the “blood testis barrier”
blood flow is on the outside of the tubule in the interstitial area.. in the luminal area there is developing spermatotids.. so it permits the developing spermatocytes to be blocked from any sort of signaling from the vasculature. once the cells move out into the luminal compartment they’re haploid..
so it isolates the haploid germ cells from systemic circulation (i.e. immune system) (secondary spermatocytes, spermatids, sperm)
how do cells move from the basal compartment to the luminal compartment if we have tight junctions?
what’s present in each compartment?
the junctions break and cells get shifted and push out towards that luminal area..
spermatogonia and primary spermatocytes are found in the basal compartment
when the primary spermatocyte is formed it’s pushed through the junctional complexes where it transitions to later stages.
luminal compartment has more mature spermatocytes and early/late spermatids.
What type of “genesis” of the cells happen in the luminal compartment?
meiosis and spermiogenesis
why are Sertoli cells called “nurse cells”?
1) what do they provide for the sperm?
2) what do they do cleaning up the area?
take care of the developing sperm.
the provide nutrients and remove waste..
but also phagocytose residual bodies (spermatogenesis) and spermatogenic cells that fail to differentiate!
what’s to note about spermatogonia as it goes from basement membrane to being more developed?
spotted, speckled chromatin are the primary spermatocytes and spermatogonia
as the cells continue to develop and move to the lumen the nuclei become more uniform = early spermatids
at some point the nuclei become elongated and pushed out.. those are LATE spermatids.
What does the blood testis barrier separate division wise?
haploid from diploid
Interstitial cells?
1) what do they do,
2) where are they found,
3) why are there white granules inside?
cells that are present in the interlobular space very close to the blood supply
these are steroid producing cells that produce 95% or so of the testosterone.
androgens don’t stain very well
what is the spermatogenic cell sequence?
2 types of spermatogonia and what do they do? what kind of division do they do?
what do you get from one of the spermatogonia? what does this now start dividing by?
from 1*, what happens until sperm?
Type A spermatogonia –> those that are truly sperm stem cell.. these divide to produce its own copy of itself and a type B.
Type A remains in the basal compartment as the precursor MITOSIS
Type B move on in their purpose and start to divide to produce primary spermatocytes through MITOSIS
right after that first division they enter meiotic prophase as a primary spermatocyte.. it will then be pushed out!
Spermatocytes divide by meiosis to form primary spermatocytes –> 2ndary spermatocytes (2 of them) –> differentiate to early Spermatids –> late spermatid.
difference between spermatids?
1) nuclei?
2) what is removed and what removes it?
early spermatid –> have round nuclei
late = nuclei and other components are produced and the it’s more elongated nuclei
eventually it will be be completely removed as residual bodies. (Sertoli cells removed)
interesting to know about sperm formation?
what kind of division do they do?
they are attached to each other.
the divisions are in unison!
where do you see type a and b spermatogonia?
in the basal compartment (before the barrier)
where do you see primary spermatocytes?
secondary?
mostly in the luminal (more round)
mostly in the luminal compartment (more columnar)
Early vs late spermatid:
1) shape
2) where are they housed
3) what are they undergoing and what are they losing?
early are round, late are elongated.
early is housed in the luminal compartment of the sertoli cells
the late spermatids are even deeper invaginations in sertoli apical cytoplasm.
they’re undergoing spermatogenesis where they’re losing those inner cellular bridges, those residual bodies… and they’re undergoing changes of the cytoplasm in order to create different components of the mature sperm.
what do elongated (late) spermatids develop?
acrosome (head of the sperm), mid piece (mitochondria in it), and tail, which technically is a flagella
what happens when we have mature spermatids?
1) what’s the process called?
explain from the start of late spermatids
they are released
via “Spermiation”
they lose the intercellular bridges –> lose residual bodies –> lost and mature spermatids are separated, released into the lumen and propelled too the epididymal duct.
Structure of the sperm?
1) what’s in the head and what does it do?
2) what’s in the mid piece?
3) what is the last 2 pieces?
Head and tail –> surrounded by a plasma membrane
Head has an acrosome –> a lot of proteolytic enzymes for the sperm to digest the zona pellucida of the oocyte.
it has a mid piece region which has a lot of the microtubule components and mitochondria for sperm motility
principle piece of the tail, and an end piece of the tail to induce swimming
