Flashcards in Male Reproductive Histo Deck (66):
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
What occurs in the Golgi phase of spermiogenesis?
characterized by the presence of PAS-positive granules that coalesce into a membrane bound vesicle, the acromosomal vesicle whose position determines the anterior pole of the sperm
What occurs in the cap phase of spermiogenesis?
acrosomal vesicle spreads over the anterior half of the nucleus -> acrosomal cap
What occurs in the acrosomal phase of spermiogenesis?
head reorients to point toward the basal lamina while the developing flagella extends into the lumen of the seminiferous tubule & the nuclei elongate
What occurs in the maturation phase of spermiogenesis?
loss of cytoplasmic bridges & reduction of excessive cytoplasm which is phagocytosed by Sertoli cells
What are the phases of spermatogenesis?
Golgi, cap, acrosomal, and maturation
What is the make-up of mature sperm?
Head is flattened & pointed, Acrosomal cap secretes enzymes essential for penetration into the zona pellucida of the ovum (acrosomal reaction), Neck contains centrioles, Middle piece contains mitochondria which provide the energy for movement of the tail
What is spermiation?
release of the sperm from the Sertoli Cell excess cytoplasm remains in the cell
What happens to sperm in the epididymis?
site where sperm acquire motility due to changes in cAMP & Ca2+ levels, Condensation of nuclear DNA, Head becomes more slender, Further reduction of cytoplasm, Alteration in the outer acrosomal membrane (decapacitation)
What is the pathway of sperm?
seminiferous tubules, tubuli recti, rete testis, ductuli efferents, ductus epididymis, ductus deferens, ejaculatory ducts, urethra, penile urethra, urethral orifice
Where does the bulbourethral gland empty?
Where does the prostate gland empty?
Where does the seminal vesicle empty?
What gives rise to the excurrent duct system for the developing testis
mesonephric duct and its tubules
What are the histological features of the tubuli recti (straight tubules)?
short, straight tubules lined by simple cuboidal epithelium. They carry the newly produced spermatozoa from the seminiferous tubules to the rete testis, devoid of spermatogenic cells
What are the histological features of the rete testis?
a maze of anastomosing tubules with an irregular lumen lined by simple cuboidal epithelium. This network conducts spermatozoa into the efferent ductules
What are the histological features of the efferent ductules?
convoluted tubules lined by two cell types: pseudo stratified short nonciliated cuboidal cells and tall ciliated columnar cells. sawtooth appearance. both with numerous microvilli. Smooth muscle cells form a circular layer several cells thick in the wall of the ductule. Interspersed among the muscle cells are elastic fibers
What is the mediastinum testis?
dense capsule of the testis, the tunica albuginea, thickens on the posterior side , gives off many tiny septa that separate the lobules
What is the function of efferent ductules?
absorb some testicular ﬂuid, Transport of the sperm in the efferent ductules is affected largely by both ciliary action and contraction of this fibro-muscular layer.
What is the make-up of semen?
secretory products from the epididymis, vas deferens, prostate, seminal vesicle, and bulbourethral glands, contain prostaglandins that influence sperm transit in both the male and female reproductive ducts, ~25% of sperm in any ejaculate are morphologically abnormal and/or immotile
What is the make-up of epididymis?
efferent ductules make-up the head, duct of the epididymis makes up the body and tail; Motility of sperm is achieved in the duct of the epididymis
What are the functions of the epididymis?
Sperm maturation including stabilization of chromatin, changes in plasma membrane surface charge, acquisition of new surface proteins, acquisition of sperm forward motility, Sperm storage until ejaculation, Sperm transport by peristalsis to the storage region in the tail
What are the histological features of the epididymis?
duct is lined by a pseudostratified columnar epithelium with long stereocilia (arrows). X140. H&E.epithelium is surrounded by a thin circular layer of smooth muscle, enclosed by connective tissue with many blood vessels (V) and covered by a capsule and the tunica vaginalis, fewer small basal stem cells abutting the basal lamina, Principal Cells: contain long microvilli (stereocilia); aid in maturation of sperm, Intraepithelial lymphocytes
What is the function of the stereocilia?
Extremely long processes that extend from the apical surface & facilitate absorption & resemble hairs of a paint brush; resorption of residual bodies eliminated during spermatogenesis
What is the makeup of the spermatic cord?
ductus deferens, Pampiniform plexus of veins, Testicular artery, Nerves, Cremaster muscle, Small arteries to the ductus deferens
What is the histological make-up of the ductus deferens?
lamina propria is rich in elastic fibers and the thick epithelial lining shows longitudinal folds, ﬁngerlike mucosal folds extending into the lumen, lining is pseudostratiﬁed columnar epithelium, with basal cells and many columnar cells, some with stereocilia, thick muscularis with inner and outer layers of longitudinal smooth muscle, middle circular smooth muscle, and an external adventitia
What is the makeup of the secretions from the seminal vesicles?
up 70% of the semen volume, Rich in fructose, prostaglandins & proteins providing sperm with energy
What is the makeup of the secretions from the prostate gland?
rich in proteolytic enzymes & acid phosphatases
Reduces acidity of urethra, helps dilute (liquefy) semen, provides medium for sperm
What is the makeup of the secretions from the bulbourethral gland?
abundant galactose and sialic acid, and are emptied into the penile urethra.Secretion has a lubrication function and proceeds emission of semen (pre-ejaculate).
Where are the seminal vesicles located and what is the makeup of the gland?
Paired, elongate & highly tubular glands located on the posterior wall of the bladder, mucosa in primary, secondary, and tertiary fold, increase the secretory surface area, pseudostratified columnar epithelium, nonciliated columnar cells and short, round cells that rest on the basal lamina, morphology of protein-secreting cells, with a well-developed rER, large secretory vacuoles in the apical cytoplasm fibroelastic lamina propria and inner circular, outer longitudinal smooth muscle
Where are the bulbourethral glands located and what is the makeup of the gland?
Small, paired glands located in the deep perineal pouch, mainly of mucous acini, secretory cells are cuboidal, low columnar, or squamous and light staining, Smaller excretory ducts from the secretory units may be lined with secretory cells, whereas the larger excretory ducts exhibit pseudostratified or stratified columnar epithelium, fibroelastic capsule that surrounds these glands contains connective tissue, smooth muscle fibers, and skeletal muscle fibers in the interlobular connective tissue septum
Where is the prostate gland located and what is the makeup of the gland?
Sits inferior to the bladder surrounding the urethra, many individual tubuloacinar glands lined by simple or pseudostratified columnar epithelium, some containing concretions called corpora amylacea, central zone, peripheral zone, transitional zone, periurethral zone, A fibromuscular stroma occupies the anterior surface of the prostate gland anterior to the urethra composed of dense irregular connective tissue with large amounts of smooth muscle fibers.
What are the characteristics of the central zone of the prostate gland?
surrounds ejaculatory ducts; resistant to carcinoma; comprises 25% of glandular tissue
What are the characteristics of the peripheral zone of the prostate gland?
occupies the posterior & lateral aspects of the gland & thus is palpable during a rectal exam; most susceptible to cancer; comprises 70% of glandular tissue
What are the characteristics of the transitional zone of the prostate gland?
surrounds prostatic urethra, contains mucosal glands; site of benign prostatic hyperplasia; comprises 5% glandular tissue
What are the characteristics of the periurethral zone of the prostate gland?
mucosal & submucosal glands
What is the course of the ejaculatory ducts?
pass through the posterior part of the prostate, along the sides of the prostatic utricle to open on the seminal colliculus as apertures near the prostatic utricle
What is the course of the prostatic ducts?
open into the prostatic sinuses that lie on either side of the seminal colliculus on the posterior wall of the prostatic urethra
What is the course of the ducts of the bulbourethral glands?
open through minute apertures into the proximal part of the spongy urethra in the bulb of the penis
What is corpora amylacea?
Calcified prostatic secretions that typically display concentric rings & increase with age