Male Reproductive System I Flashcards
What is testicular determining factor (TDF)?
A transcription factor from the Y chromosome that causes fetal gonad differentiation.
How are the primitive sex cords formed? What do these eventually become?
When primordial germ cells from the yolk sac endoderm migrate into the genital ridge. Eventually becomes the serminiferous tubules.
What do Sertoli cells, intersitial cells, and CT derive from?
Mesoderm.
What is the tunica vaginalis?
The double-layered covering of the anterior testis.
What is the testicular capsule made of? What is a fancy word for it?
AKA tunica albuginea. Made of dense fibrous CT.
What is the mediastium testis? What other important structure is found here?
An area of the posterior testis where the CT of the tunica albuginea gets thick. The rete testis is found here.
Where is the tunica vasculosa found and what does it contain?
Found deep to the albuginea in the testis, contains lymphatics and blood vessels.
What separates testicular lobules? How many seminiferous tubules are found in each lobule?
CT septa separates. 1-4 tubules per lobule.
What type of epithelium is found in the seminiferous tubule wall?
Stratified seminiferous epithelium.
What cells are found deep to the basal lamina in the seminiferous tubules?
Contractile peritubular myoid cells, fibroblasts, CT.
What two cell types are found in the seminiferous tubules?
- Spermatogenic cells
2. Sertoli cells (supporting cells)
What are the four phases of spermatogenesis?
- Spermatocytogenesis
- Meiosis
- Spermiogenesis
- Spermiation
What happens during spermatocytogenesis?
Generation of primary spermatocytes.
What is spermiogenesis?
Cytodifferentiation
What is spermiation?
Release of spermatozoa (sperm) from the sertoli cells.
In which spermatogenic cells does crossing over take place?
Primary spermatocytes.
What do Type A and B spermatogonia do?
Type A remain stem cells. Type B differentiate.
Which spermatogenic cell moves up from the basal lamina in seminiferous tubules?
Primary spermatocytes.
Which spermatogenic cell is the largest and most prominent in histologic sections?
Primary spermatocytes.
What do secondary spermatocytes look like in histologic sections?
Trick question! They have a short half life and are rarely seen!
What do early spermatids look like?
Small round cells with a heterochromatic nuclei.
What do late spermatids look like?
Condensed nuclei and tapered cell body with a tail.
When are the cytoplasmic bridges between spermatogenic cells broken?
When they are released into the lumen of the seminiferous tubule. This is called the “clonal nature of sperm development.” -sounds like something Dr. G would be stoked on.
What are the five steps of spermiogenesis?
- Acrosome formation.
- Centriole migration and flagellum formation.
- Mitochondria migration.
- Condensation of the nuclear chromatin.
- Sloughing of residual bodies.
What does the acrosome arise from?
The Golgi.
What is found in the acrosome?
Enzymes!
Hyaluronidase, neuraminidase, acid phosphatase, trypsin-like protease, and other PAS-positive carbohydrate rich components!
What is a residual body?
“Extra” cytoplasm of spermatozoa that glob off before they are released into the lumen.
What do Sertoli cells look like? What are they under the influence of?
Long cells that sit on the basal lamina and extend towards the lumen of the seminiferous tubule. Under influence of FSH.
Name five things that Sertoli cells do.
- Form gap junctions with neighboring cells.
- Form the blood-testis barrier.
- Phagocytose residual bodies.
- Secrete fluid, androgen binding protein (ABP), activin, and inhibin.
- Physical support.
What do activin and inhibin do?
Activin stimulates FSH from pituitary. Inhibin inhibits.
What is found in the spaces between seminiferous tubules?
Interstitial containing CT, nerves, blood, lymphatic vessels, and Leydig cells.
What are Leydig cells derived from?
Embryonic genital ridge mesoderm.
What do Leydig cells do? What are they inder the influence of?
Secrete testosterone, DHEA, and 5-alpha-androsteindione. Under influence of LH
Why is the blood-testis barrier important?
Spermatogenesis does not occur until after puberty, so the proteins created during the process may be considered “foreign” by the immune system. The barrier blocks immune attack.
Junctional complexes on the _________ aspect of Sertoli cells make up the blood-testis barrier.
Lateral
What are the two compartments of the seminiferous tubule with regard to the blood-testis barrier?
- Basal compartment
2. Adluminal compartment.
Are spermatogonia and spermatocytes that are touching the basal lamina accessible by things that cross the basal lamina?
Yup
Define the adluminal compartment of the seminiferous tubule.
The area between the Sertoli cell lateral junctional complexes and the lumen.
Which spermatogenic cells can one find in the albuminal compartment of the seminiferous tubule?
Primary, secondary spermatocytes, and spermatids.
What happens to testosterone in the seminal vesicles, bulburorethral glands, and external genetalia?
Converted to DHT by 5-alpha-reductase.
What happens to testosterone in the peripheral tissues?
Converted to estradiol by aromatase.
What is prolactin’s role in the male reproductive system?
Increases the effect of LH on Leydig cells.
What effect does FSH/LH have on Leydig cells?
Stimulates them to make testosterone.
What is cryptorchism?
Failure to descend.
What is the order of ducts that a sperm will encounter, beginning at the seminiferous tubule?
Seminiferous tubule –> rete testis –> duculi efferentes –> epididymis –> ductus deferens
Spermatogonia have __N DNA.
2N DNA. These are the precursor cells for meiosis.
Primary spermatocytes have __N DNA.
4N. These have copied their DNA prior to any meiotic division.
Secondary spermatocytes have __N DNA.
2N DNA. They have done the first meiotic division.
Spermatids have __N DNA.
1N DNA. They have completed meiotic divisions.
