- connects the seminiferous tubules with the epididymis

Straight tubules --> Rete testis --> Efferent ductules

- joins with the vas deferens to create the ejaculatory duct before draining into the urethra

Seminal vesicle

- part of urethra where the bulbourethral glands secrete their product

Membranous urethra

- produces sperm (exocrine)

- produces androgens (endocrine)

- seminal fluid production

- erection (parasympathetic)

- ejaculation (sympathetic)

Functions of Male Reproductive System

- originates from the internal oblique muscle

- surrounds its namesake's muscle

Cremasteric fascia

- the external oblique aponeurosis extends to create this fascia around the spermatic cord

External spermatic fascia

- the origin of the internal spermatic fascia

Transversalis fascia

- major cooling force for the testis

- from the testicular veins

pampiniform plexus

- protects and helps maintain testis temperature a few degrees lower than body temp

- skin with smooth muscle layer (dartos tunic)

Scrotum

- flattened serous sac derived from the peritoneum during descent

- visceral layer adheres to anterior and lateral testis capsule

Tunica vaginalis

- thick, white, dense CT capsule

- protective encasement that conducts blood vessels, nerves, and lymphatics

Tunica albuginea

- posterior thickening of the tunica albuginea that penetrates into the testis

- contains the rete testis

Mediastinum testis

- CT partitions converging on the mediastinum from the tunica albuginea

- divides testis into about 250 wedge-shaped lobules

Septa

- clusters of endocrine-secreting parenchymal cells

- eosinophilic ovoid cells with euchromatic spherical nucleus

- abundant smooth ER, tubular cristae, lipid droplets, cytoplasmic crystals of Reinke

- secrete testosterone after LH influence

Interstitial cells of Leydig

- masculinization of fetal brain

- development of Wolffian duct system (mesonephric)

- support of spermatogenesis

- secondary sexual characteristics

- maintenance of ducts and reproductive glands

- male mating behavior

- general anabolic effects (bigger)

Effects of Testosterone

- connected at both ends to rete testis

- lines the tubule lumen

- surrounded by basal lamina basally, external to that is tunica propria

- contain sertoli cells

Seminiferous (germinal) epithelium

- contractile properties, located in tunica propria

- help propel spermatozoa forward

Myoid cells

- tall, pyramidal cells extend from basal lamina to lumen

- large nucleus, euchromatic, random shape (traingular)

- prominent nucleolus, not distinct cell limits

- base is blood-testis barrier

- apical side is immunologically protected zone (for developing sperm)

Sertoli cells

- transport of nutrients to germ cells

- blood-testis barrier formation

- engulf & digest germ cell cytoplasm (excess)

- produce testicular fluid

- secrete androgen binding protein

- inhibits release of FSH

- assist migration, differentiation, and release of germ cells

Functions of Sertoli cells

- only mitosis, mainly stem cell-like function

Type A dark spermatogonia

- only type of spermatogonia that leaves the seminiferous tubules

- cross blood-testis barrier

Type B (dark)

- longest stage of spermatogenesis

- 22 days in prophase

Primary --> Secondary

(1st meiotic division)

- nuclear condensation

- acrosomal cap formation

- flagellum formation

- cell appendage contains excess cytoplasm

cytodifferentiation of spermatids (1N)

- not yet motile, carried by testicular fluid

- propelled by myoid cells

- few remaining synthetic organelles

- mitochondrial neck region (sheath), generates twitches

- residual bodies ingested by Sertoli cells

Spermatozoa

- simple cuboidal epithelium

- connect seminiferous tubules to rete testis

- simple columnar (Sertoli cells) --> cuboidal as they become straight

Straight tubules

- anastomotic network of channels

- simple cuboidal epithelium w/ microvilli and 1 cilium/cell

- conducts spermatozoa

Rete Testis

- traverse tunica albuginea to posterosuperior surface

- highly convoluted, forming inverted cone-shaped lobule

- 12 or more join to duct of epididymis

- scalloped shaped lumen made of tall/short cells

- propel sperm and reabsorb testicular fluid

- well vascularized

Efferent ductules

- Tall columnar ciliated cells forming linear ridges

- shorter nonciliated absorptive cells forming linear troughs

- pseudostratified columnar epithelium

Efferent ductule lumen

- single convoluted duct forming coma-shaped organ

- clasps behind testis

- made of 3 regions: head, body, tail

- provide nutrients to sperm and reabsorb testicular fluid

- pseudostratified columnar epithelium w/ stereocilia (actin filament core microvilli)

Epididymis

- superior region where efferent ductules join

- thin circular coat of smaller cells with fewer myofilaments

Head of Epididymis

- posterior to testis

- promote sperm maturation, motility, and capacitation

- thicker circular coat plus outer longitudinal bands of larger smooth muscle cells

Body of Epididymis

- principal site of sperm storage

- continuous with vas deferens

- has complete outer longitudinal layer and additional inner longitudinal muscularis (distal)

- innervated by adrenergic sympathetic nerves (ejaculation)

Tail of Epididymis

- wider lumen, thicker wall, thinner epithelium

- longitudinal mucosal folds create irregular lumen

- three muscle layers

- transit of sperm is rapid

- ampulla found at its terminus

- occluded/clipped during vasectomy

Vas Deferens

- expanded chamber near junction with seminal vesicle duct

- elaborate mucosal folds and pockets

- lower columnar secretory cells

Ampulla of Vas Deferens

- formed by seminal vesicle duct and ampulla of vas deferens

- penetrate prostate from behind and converge on urethra at the colliculus seminalis

- epithelium is simple columnar --> transitional

Ejaculatory Ducts (paired)

- thickening of the posterior wall of the prostatic urethra

- site of convergence of urethra and ejaculatory ducts

Colliculus seminalis

- shallow blind pouch in urethral wall between ejaculatory duct openings

- homologue of uterus

Utriculus masculinus

- coiled, convuluted, tubular structure w/ voluminous luminal stored secretion

- extensively folded creating mucosal pockets

- simple/pseudostratified columnar, secretory epithelium

- circular/longitudinal smooth muscle + thin outer fibroelastic adventitia

- secrete yellowish-brown thick nutritive fluid

Seminal Vesicles

- fructose and citrate

- semenogelin (coagulates semen)

- prostaglandins

Seminal vesicle secretion

- comprised of 30-50 tubuloalveolar glands

- pseudostratified cuboidal or columnar epithelium

- concretions can be found in gland lumens w/ age

- glands surrounded by fibromuscular stroma

- made of 3 zones

- secrete thin, milky fluid

Prostate

- 50:50 mix of smooth muscle and CT

- glands of prostate found here

Fibromuscular stroma

- have 5a reductase (converts T to DHT)

- stimulates production of mitogenic growth factors

- cause proliferation of stroma and gland cells

Stromal cells of Prostate

- zone of Prostate that usually does not experience cancer or benign prostatic hyperplasia

Central zone of Prostate

- primary location where benign prostatic hyperplasia (BPH)

- lies around prostatic urethra

Transitional zone of Prostate

- major site of prostatic cancer

Peripheral zone of Prostate

- thin, milky fluid

- contains acid phosphatase, amylase, fibrinolysin (liquefies semen), serine protease (PSA)

- prostasomes (cholesterol, sphingomyelin, calcium)

Prostatic secretion

- PSA serum levels that indicate prostatic cancer cells

Elevated

- compound, tubuloalveolar glands with mucus-secreting alveoli

- secretes clear mucus just prior to ejaculation to prepare urethra

Bulbourethral glands

- contains the urethra

- not constrained by a capsule (doesn't become stiff)

- single erectile body in penis

Corpus spongiosum

- paired, true erectile bodies

- surrounded by thick CT sheath (tunica albuginea)

- incompletely separated by a sagittal CT septum

- endothelium-lined cavernous sinuses subdivided by smooth-muscle containing trabeculae

- triggered by parasympathetic (NO release)

Corpora cavernosa

- triggered by parasympathetic nerve NO release

- causes production of cyclic GMP --> calcium sequestration in smooth muscle cells --> relaxes muscle

- cavernous spaces fill with blood --> compress effluent veins against tunica albuginea

Penile Erection

- reverse of erection

- reduced parasympathetic, muscles contract

- phosphodiesterase breaks down cyclic GMP

- effluent veins decompressed

- viagra inhibits phosphodiesterase (fun fact)

Detumescence

- distal expansion of corpus spongiosum

- contains navicular fossa (expansion of urethra at termination)

- highly sensitive due to numerous nervous receptors

- stratified squamous epithelium (keratinized in circumcised individuals)

Glans of penis

- retractable fold of skin covering the glans of uncircumcised individuals

- removal decreases risk of HIV infection and protects men/women from human papillomavirus infection/cervical carcinoma

Prepuce