Male Reproductive Histo Flashcards
What is the tunica vaginalis?
closed peritoneal sac which contains fluid to allows the testes to move freely within the scrotum; visceral and parietal
What are lobules in the testes?
Testes are subdivided into ~250 lobules which each contain 1-4 seminiferous tubules & a connective tissue stroma
What are the seminiferous tubules?
coiled tubuless where spermatozoa are produced and develop.
What are the straight tubules of the testes?
connect the seminiferous tubules to the rete testis, a network of canals in the mediastinum of the testis
What is the tunica albuginea?
tough, outer, fibrous connective tissue layer that thickens for form the mediastinum which sends fibrous septa anteriorly between lobules
What is the make-up of the interstitial stroma?
intertubular connective tissue and Leydig cells
What is the make-up of the lamina propria?
peritubular connective tissue and Myoid cells
What are the leydig cells and where are they located?
Endocrine cells that secrete testosterone during embryonic development, sexual maturity and for maintenance of spermatogenesis; interstitial stroma near capillaries & between the seminiferous tubules; derive from the mesoderm
What are the histological features of leydig cells?
Large, polygonal, eosinophilic cells that have round nuclei and pale-stained cytoplasm with lipid vacuoles, which give them a bubbly appearance
What is the role of the leydig cells in an embryo?
secretion of testosterone and other androgens is essential for the normal development of the gonads
What is the role of the leydig cells in puberty?
secretion of testosterone is responsible for the initiation of sperm production, accessory sex gland secretion, and development of secondary sex characteristics
What is the role of the leydig cells in adulthood?
: secretion of testosterone is essential for the maintenance of spermatogenesis & secondary sex characteristics, genital excurrent ducts, and accessory sex glands
What are the histological features of myoid cells? Where are they located?
4-5 layers of flattened smooth muscle-like cells of mesodermal origin; Create a contractile connective tissue external to the basal lamina of the seminiferous epithelium
What is the function of the myoid cells in the testicle?
Create peristaltic waves that help move spermatozoa & testicular fluid out the seminiferous tubules
What is the make-up of seminiferous epithelia?
several layers thick and contains 2 types of cells: Sertoli cells & spermatogenic cells
What are the histological features of the sertoli cells?
Tall, columnar, non-replicating epithelial cells with an ovoid or triangular euchromatic nucleus. The cells span from the basement membrane to the lumen of the tubule, many folded cytoplasmic processes forming compartments for the spermatogenic cells, form tight junctions (zonulae occludentes) with the neighboring Sertoli cells- blood-testis barrier to protect spermatogenic cells from being harmed by autoimmune reactions
What is the function of the sertoli cells?
Physical support, protection, nutrition, & release of mature sperm into tubules, Phagocytosis of residual cytoplasm of spermatids during sperm development, Synthesis and release of androgen-binding protein (facilitates increase in testosterone), Synthesis and release of anti-Müllerian hormone to prevent development of müllerian duct (precursor to female Repro. System)
Synthesis and release of inhibin that blocks release of FSH by anterior pituitary
What are the 3 phases of spermatogenesis? when does it happen?
Spermatogonial phase, Spermatocyte phase, Spermatid phase; puberty throughout life
What occurs in the spermatogonial phase?
spermatogonia divide by mitosis for a continual supply
What occurs in the spermatocyte phase?
meiosis: primary spermatocytes undergo 2 meiotic divisions to reduce the chromosome # & DNA haploid cells called spermatids
What occurs in the spermatid phase?
spermiogenesis: spermatids differentiate into mature sperm
What are the histological features of spermatogonia?
These cells have round or oval nuclei parallel to the basement membrane and are located near the basement membrane. Dark A- reserve stem cells. They give rise to other dark A and pale A, Pale A-progenitor cells. They stain lighter because of abundant euchromatin. They give rise to other pale A and type B, Pale B-give rise to primary spermatocytes which immediately move into the adlumenal compartment of the seminiferous tubule,
What are the histological features of spermatocyte?
derivatives of spermatogonia B cells undergo meiosis, primary (first meiotic division) spermatocytes, secondary (second meiotic division) spermatocytes, large nuclei contain strands of condensed chromosomes
What are the histological features of spermatids?
small interphase nuclei that range from spherical to thin and elongated, classified mainly on the appearance of the nucleus: early-small spherical interphase nuclei, intermediate-nucleus broad diamond shape and late- nucleus has assumed the sharply pointed shape and dense appearance of a spermatozoan
What is the function of the blood testis barrier?
protects developing cells from the immune system by restricting the passage of membrane antigens from developing sperm into the bloodstream, also keeps harmful substances in the blood from entering the developing germinal epithelium
What is spermiogenesis?
Differentiation of spermatids into spermatozoa (mature sperm).Spermatids discard much of their cytoplasm, rearrange their organelles and form a flagellum to become spermatozoa. Nucleus becomes elongated, condenses, and is reshaped into the main bulk of sperm head, Golgi Apparatus migrates to “top” of nucleus to form the acrosome
Mitochondria localize in the middle piece