Histology of the Male Repro Tract Flashcards
1) Identify cells, tissues, and organs of male reproductive system 2) Know structure-fxn relationship of male reproductive system 3) Describe meiosis in male germ line/ know the genetic make up of various male germ cells 4) Know the functions of Sertoli cells 5) Know the composition and function of blood/testis barrier
Primary spermatocytes: 1n/ 2n/ 4n? Diploid or haploid?
4n and diploid (Non sister chromatids have exchanged genetic information after synapsis)
Secondary oocytes / spermatocytes: 1n or 2n? Diploid or haploid?
2n but haploid. (homologous chromosomes have separated)
What’s the tough layer around the testis that forms septations?
Tunica albuginea.
Fibrous capsule that penetrates testes and divides it into lobules (where spermatogenesis takes place). Each lobule contains 1-4 seminiferous tubules.
Why are there macrophages in the seminiferous tubules?
To clean up debris / malformed sperm.
What are 2 types of cells in the intertubular spaces of the testis?
Leydig cells and macrophages.
What are 2 types of cells in the wall of the seminiferous tubules?
Fibroblasts
Myoid cells
What kinds of cells are in the seminiferous epithelium?
Sertoli cells and spermatogenic cells.
What do myoid cells do? What hormone do the respond to?
Contractile activity helps move developing spermatozoa into the lumen. Contain components of smooth muscle (actin filaments). Respond to testosterone
What do Leydig cells look like?
Light, foamy cytoplasm due to the presence of steroids.
2 broad functions of testosterone produced by Leydig cells?
1) Maintain seminiferous epithelium locally.
2) Induce / maintain secondary sex characteristics distantly.
Why keep spermatids connected by cytoplasmic bridges?
So that proteins that Y-only spermatids lack can be exchanged. Also helps with communication so that maturation can occur in sync
Specific protein mentioned that is necessary for cytoplasmic bridges between spermatids?
TEX14–> if you make mouse knock-outs–> spermatogenesis fails
What does “spermatogenesis occurs in waves” mean?
If you look at cross sections of seminiferous tubules, you’ll probably only see one stage of spermatogenesis per tubule.
How type S(A) and S(B) spermatogenic cells compare?
S(A): round, dense nuclei, dark staining= LEAST MATURE
S(B): more open/dispersed chromatin, nucleoli, about to enter meiosis
Very brief description of S1, S3, and S4 spermatogenic cells? Where are S2?
S1: duplicated DNA
S3: round spermatids
S4: look like spermatozoa
S2 are not seen- they are present VERY TRANSIENTLY–> quickly undergo Equational Division and become S3
Where do acrosomal vesicles come from? What is the function of the acrosome?
Coalesced lyosomal vesicles that came off the Golgi…
Acrosome spreads all the way around sperm head and contains enzymes that will drill through the ZP of the egg and allow the sperm to inject it’s nuclear material
What’s special about the microtubule arrangement in the spermatozoan flagellum?
9 outer doublets, 1 inner doublets
What structures seem to play an important role in initiating flagellum formation?
The centrioles–> they migrate to opposite side of the nucleus
What’s Kartagener syndrome? What causes it? What’s a common co-morbidity?
Immotile sperm.
Often caused by genetic defect in dynein or some other MT-related molecule.
Men with it often have frequent respiratory infections due to impaired cilliary motion in the lungs.
5 functions of Sertoli cells?
1) Support, protect, nourish spermatogenic cells.
2) Phagocytose debris.
3) Secrete androgen-binding protein, inhibin, and activin.
4) Produce anti-Mullerian hormone (during fetal devo.)
5) Help form blood-testis barrier.
What stages of spermatogenesis are more protected from blood-borne products?
More advanced stages…
Through what must spermatozoa travel to reach the epididymus?
Seminiferous tubules -> rete testis -> ductus efferentes -> epididymus
4 aspects of sperm maturation that happen in the epididymus?
1) Stabilization of condensed chromatin.
2) Changes in plasma membrane charge.
3) Changes in surface proteins.
4) Acquisition of motility.
Special histological feature of epithelium of the epididymus?
Stereocilia (which are really long microvilli)
