Tunica albuginea: connective tissue cortex of the testis (and ovary)

Acrosome: anterior organelle of the spermatozoon head that contains hydrolytic (fertilizing) enzymes; modified from the Golgi apparatus of the differentiating spermatid

Residual body: cytoplasmic by-product of spermiogenesis that is resorbed by Sertoli cells

Cytoplasmic droplet: small amount of cytoplasm that is retained by the spermatozoon upon release into the lumen of the seminiferous tubule; inhibits sperm motility; is removed within the epididymis

Corpora cavernosa: (dominant) dorsal bodies of the penis that become engorged with blood (vasodilation) during sexual excitement

Corpus spongiosum: erectile tissue surrounding the urethra

Vascular penis: erection is caused by filling of the vascular sinuses (man, stallion)

Fibroelastic (semi-rigid) penis: erection is due mainly to straightening of the sigmoid flexure (ruminants, boar, cetaceans)

Os (bony) penis: calcium deposition within the cavernous sinuses (carnivores, rodents, bats, some primates)

BPH: benign prostatic hyperplasia/hypertrophy; an age- and androgen-dependent overgrowth of the prostate gland; urethral obstruction causes difficult urination

Concretion: calcium deposit in the duct system of the prostate gland

Blood-testis barrier: an occluding network of junctional complexes that interconnect Sertoli (and epididymal) cells; prevents autoimmune recognition of sperm cells that have undergone meiosis I

Cryptorchidism: postnatal failure of testicular descent (sterility if bilateral)

Spermiation: release of spermatozoa from the seminiferous epithelium

Semen: sperm + seminal plasma

 

Seminiferous (tubular) compartment of the testis: sperm cells develop between the Sertoli cells that line the convoluted tubules which comprise > 80% of the testicular mass (large surface area for spermatogenesis); nerves and blood vessels do not penetrate the supporting basement membrane of the seminiferous epithelium (avascular)

Interstitial compartment: loose connective tissue/vascular matrix that surrounds the seminiferous tubules and contains Leydig cells

 

Sertoli cell functions: support of sperm cells; nutrition of sperm cells; transport of sperm cells; phagocytosis of dead/defective cells and residual bodies; immune protection (blood-testis barrier); steroidogenesis (E2); inhibin production; ABP production

 

Sperm tail: neck > middle piece (mitochondria/energy) > annulus > principal piece > end piece

Axoneme: microtubular/fibril core of the sperm tail that imparts motility; derived from the distal centriole during spermiogenesis

 

Male duct system: seminiferous tubules > tubuli recti > rete testis > efferent ducts > epididymis > vas deferens > urethra

 

Epididymal functions: sperm transport; sperm storage (ejaculated from cauda); maturation (loss of cytoplasmic droplet); resorption of dead/defective sperm cells

 

Accessory glands: seminal vesicles; prostate (common to all mammals); bulbourethral (Cowper's); ampulla; coagulating (vaginal plug in rodents); urethral (disseminate prostatic tissue); [preputial - pheromone production]; functional integrity is androgen-dependent (testosterone > DHT)

 

Functions of seminal plasma: fructose (energy for spermatozoa); buffer (against acidic vagina); prostaglandins (female tract contractility); decapacitation (acrosomal inhibitors)

 

Most voluminous and concentrated farm animal ejaculates: boar and ram, respectively

 

Hypothalamic (MBH/ARC)-pituitary-testicular endocrine axis: GnRH > LH > testosterone > decreased GnRH > decreased LH > decreased testosterone > increased GnRH � (pulsatile hormone production)

 

Two-cell/two-gonadotropin mechanism of testicular steroidogenesis: LH > Leydig cell > testosterone; FSH > Sertoli cell > estradiol (aromatization of testosterone)

 

CNS aromatization: stimulation of sexual behaviors; feedback control of GnRH?

 

Mitosis: clonal expansion of cells (mother > identical daughters)

Meiosis: crossing-over and recombination generate genetic variability (I); no DNA replication between serial divisions (half-chromosomal reduction; 2N > 1N)

 

Spermatocytogenesis: spermatogonia (mitosis) > primary spermatocytes (meiosis I) > secondary spermatocytes (meiosis II) > spermatids

Spermiogenesis: spermatids (metamorphosis) > spermatozoa

Hormonal control: testosterone supports mitosis and meiosis I; FSH/estradiol are involved in spermiogenesis; rate of sperm cell production is not altered by hormonal therapy

 

Testicular thermoregulation: external position; scrotal sweat glands; tunica dartos, cremaster muscle (cold > contraction; hot > relaxation); pampiniform plexus (arterio-venous heat exchange)

Intraabdominal testes: rodents (nonbreeding season); monotremes, sloth, elephant, rhinoceros, seals, cetaceans (permanent)


PUZZLE: grid, clues, solution.