Flashcards in Histology of the Male Repro Tract Deck (36)
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?
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?
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?
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)
3 functions of epididymus epithelium?
1) Resorb fluid.
2) Phagocytose stuff.
3) Secrete stuff. (glycoproteins, sialic acid, glycerylphosphocholine)
Major histological difference between vas deferens and epididymus?
Vas deferens has more smooth muscle (3 layers of it, in fact). The epithelia are about the same.
What makes over half the fluid in ejaculate? What 4 products are added to it?
Seminal vesicles (make 70%)
Fructose, Citrate, Prostaglandins, Proteins
3 types of gland in the prostate? How are they arranged?
1) Outer periurethral / submucosal glands.
2) Inner periurethral / mucosal glands.
3) Peripheral zone glands.
- Inner/ mucosal glands in CENTER
- Outer/ submucosal outside that
- PZ glands are most PERIPHERAL
3 specific things added to ejaculate by prostate?
1) Acid phosphatase
2) Citric acid
5 stages of male meiosis? What N value for each?
1) Spermatogonium (2N) (Pre-meiotic)
2) Primary Spermatocyte (4N) (undergoes REDUCTIONAL Division)
3) Secondary Spermatocyte (2N) (Undergoes EQUATIONAL Division--> secondary spermatocytes are present VERY transiently)
4) Spermatids (1N)
5) Mature sperm
About how many days does complete spermatogenesis take?
When do the cytoplasmic connections between developing sperm break?
Break when the residual bodies are taken off- aided by the Sertoli cells
What creates the Blood/Testis barrier?
The tight junctions between Sertoli cells
Divides testis into basal compartment (where less mature sperm develop) and adlumenal compartment (where more mature sperm are released)
How do Sertoli cells communicate with e/o?
Via gap junctions
Where do the ducts of the prostate empty?
Empty into the urethra