male reproductive system - sperm produced in seminiferous tubules 

• Leydig cells - secretes testosterone to form penis/scrotum
• scrotum - maintains temperature of 34 C for sperm development
• spermatogonia (germ cells) - become sperm through meiosis
  • never runs out (undergoes mitosis before 1 goes through meiosis to become sperm)
  • about 100-200 million sperm created each day
• primary spermatocyte - diploid cell that begins meiosis, produces 4 spermatids each
  • secondary spermatocyte - homologous pairs are split
  • spermatids - chromatids are split
• Sertoli cells - nurse developing sperm, convert spermatids to spermatozoa by taking extra cytoplasm
• spermatozoa (sperm) - simple cell consisting of head, body, tail
  • acrosome - vesicle on the head that has enzymes to help sperm penetrate egg

male accessory organs - sperm cannot move immediately after they’re made 

• epididymus - holds sperm for at least 18 hours while they develop ability to move
• vas deferens - tube passing into abdominal cavity
  • enters prostate gland at bladder base
  • prostrate gland - provides 30% of semen
• seminal vesicles - produces fructose fluid (60% of semen’s volume)
• urethra - carries sperm out through penis tip
  • bulbourethral glands - secrete fluid that lines the urethra for lubrication
• blood vessels in corpora cavernosa/corpus spongiosum dilate >> erection
  • ejaculation - semen ejecting from the penis
  • sperm only counts as 1% of semen