Panopto 35: Male Reproductive Flashcards
Are germ cells underneath the Sertoli cell membrane?
no they are never engulfed by the sertoli cells
What happens when you have 2 Sertoli cells together?
formation of a barrier that is dependent upon
1. cell processes of the adjacent sertoli cells overlap
2. overlap isolates spermatogonia and primary spermatocytes from later stages
what is a junctional complex (JC)
the barrier made by the Sertoli cells, definition: group of intercellular junctions that form a collective unit; one of these is a tight junction (zonula occluden)
what is underneath the junctional complex?
spermatagoina and primary spermatocytes
What is above the junctional complex?
primary spermatocytes and all later stages
what is another word for tight junction?
zonula occluden
Can this unique junctional complex be found anywhere else?
no only in the male reproductive system
what is a tight junction?
The cell membranes of the 2 cells fuse; the fusion is not uniform; it occurs in lines.
the more lines of fusion a tight junction has…
the more effective the tight junction will be
why are cells binding together?
eliminates the intercellular space to prevent things in the lumen from passing between cells and getting down to the epithelium and the basement membrane. (removes the passageway between cells)
How many parallel lines of fusion exist in the male reproductive system? Why do we need that many?
50+
what is found in the cytoplasm above the fused cell membranes?
we have flattened stacks of endoplasmic reticulum and actin filaments
how are the actin filaments arranged?
bundles of actin that overlap in a hexagonal arrangement
Where are these bundles of actin filaments positioned between?
positioned between the stacks of endoplasmic reticulum and then a fuzed cell membrane on the other side. (the actin filaments are sandwiched in between.)
function of JC?
adhesion device it glues the cells together and it acts a physiological barrier (prevents the passage of blood borne substances) Blood is not in the sertoli cells, but blood does pass by in the testis. Antibodies and other immune system stuff can’t pass through because they are too large, but smaller waste products can be exchanged through this barrier. Spermatocytes can also pass through even though they are large we dont know how this happens without compromising the barrier
What is the name for this JC?
blood testis barrier
Why is it important that the immune system doesn’t get past this barrier?
basal compartment: diploid cells (2n)
adluminal compartment: haploid cells (n)
the problem is haploid cells dont make an appearance until after birth so they are seen as foreign as antigenic so we have to hide them behind the barrier so they dont get attacked or destroyed (this can lead to male infertility)
What controls the adluminal compartment?
sertoli cells
What else, besides controlling the adluminal compartment, do the sertoli cells do?
- physical support: guide cells through the cytoplasm
- release of spermatids through the lumen (sertoli cells determine when they’re ready)
- physiological support: germ cells need androgens. androgens tend to randomly disperse everywhere. The chances of a germ cell capturing an androgen are slim. Sertoli cells help provide androgens to the germ cells. Sertoli cells CAN produce an antigen-binding protein though, and it is part of the fluid in the seminiferous tubules this ABP prevents the androgens from diffusing out of the tubule and gives the germ cells the right amount of androgen needed for development.
- sertoli cells control meiosis and mitosis
When it is attached to the epithelium, it is called what? when it detaches, its called what?
spermatid and spermatozoa or sperm
Can germ cells metabolize antigens?
yes they just cant synthesize them
what is inhibin
prevents mitosis and meiosis
what is activin
stimulates meiosis and mitosis
how do the sertoli cells control cell divisions?
by releasing inhibin and activin
can leydig, germ cells and sertoli cells synthesize androgens from cholesterol?
NO only leydig cells can synthesize androgens from cholesterol; germ and sertoli cells can NOT.
Which is worse at sythesizing androgens, Sertoli or germ cells?
sertoli cells have no ability to make androgens
