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.