Male Reproductive Histology - BGDA Flashcards
What are the 4 main components of the male reproductive system?
1 - testes/testicles
2 - genital ducts - intra and extra testicular
3 - accessory glands (prostate, seminal vesicle, bulbourethral glands)
4 - penis
What are the intra and extra testicular ducts?
Intra - straight tubules, rete testis and efferent ductules
Extra - epididymis, ductus deferens, ejaculatory duct
What is the mediastinum testis?
Thickened tunica albuginea on the posterior side of testis
What is the role of interstitial tissue?
Located between the seminiferous tubules
- connective tissue structure that contains interstitial (leydig cells)
What do interstitial leydig cells produce?
These are large round/polygonal cells with eosinophilic cytoplasm rich in small lipid droplets
- produce testosterone which stimulate the development of the secondary male sex characteristics
How many seminiferous tubules does each testis contain?
250-1000 approx
What are the features of seminiferous tubules?
Measures 150-250 um in diameter and 30-70cm in length
- a loop connected to the rete testis via straight tubule
What is the rete testis?
A network of epithelium-lined channels located within mediastinum testis
- opens into epididymis through 10-20 efferent ductules
What is spermatogenesis?
A process that begins at puberty with the proliferation of spermatogenic progenitor cells called spermatogonia
What are spermatogonia?
Small round cells occupying a basal niche in the epithelial wall of the tubules
- lie next to the basement membrane
Outline key features of Type A spermatogonia (stem cells)
- spermatogonia with dark, ovoid nuclei
- act as stem cells
- divide frequently and give rise both to new stem cells and cells with more pale-staining, ovoid nuclei that divide more rapidly as transit amplifying (progenitor) cells
Outline key features of Type A spermatogonia (progenitor cells)
These cells undergo several unique clonal divisions
- leave most of the cells interconnected as a syncytium
Outline Type B spermatogonia
These cells are more spherical and pale nuclei
- undergo final mitotic division to produce two cells that grow in size and become primary spermatocytes
What are the largest cells of the spermatogenic lineage?
Primary spermatocytes
What are key features of primary spermatocytes?
Spherical cells with euchromatic nuclei
- presence of partially condensed chromosomes in various stages of synapsis and recombination
What is the result of the division of each primary spermatocyte?
Production of two secondary spermatocytes
Why are secondary spermatocytes rare in testis sections?
They are very short-lived cells that remain in interphase only briefly and quickly undergo the second meiotic division
What does the division of each secondary spermatocyte produce?
Two haploid cells called spermatids each of which contains 23 chromosomes
What are spermatids?
Haploid cells with 23 chromosomes
What is spermiogenesis?
The final stage of spermatogenesis when spermatids differentiate to become spermatozoa