Chapter 19: Reproductive System

• Reproductive System


  play essential roles in the development of the structural and functional differences between males and females, influence human behavior, and produce offspring.
• However, a reproductive system, unlike other organ systems, is not necessary for the survival of an individual human.
• Reproductive System Functions


  Production of gametes

  Fertilization

  Development and nourishment of a new individual

  Production of reproductive hormones
• Gametes


  reproductive cells

  sperm in males

  oocytes (eggs) in females
• Meiosis


  a special type of cell division that leads to formation of gametes
• Each sperm cell and each oocyte contains 23 chromosomes
• Fertilization


  union of sperm and oocyte
• Zygote


  A fertilized oocyte

  develops after fertilization

  develops into an embryo 3 to 14 days after fertilization
• Male Reproductive System


  consists of the testes, a series of ducts, accessory glands, and supporting structures.
• Ducts of Male Reproductive System

  epididymis

  the ductus deferens

  urethra
• Accessory glands of Male Reproductive System

  Seminal vesicles

  Prostate gland

  Bulbourethral glands
• Supporting structures of Male Reproductive System

  Scrotum

  Penis
• Scrotum


  contains testes, dartos muscle, and cremaster muscles
• Dartos Muscle


  moves scrotum and testes close to and away from body depending on temperature
• Cremaster muscles


  extensions of abdominal muscles can contract and pull the testes nearer the body
• Testes


  primary male reproductive organ

  produces sperm

  in scrotum

  contains seminiferous tubules
• Seminiferous tubules


  where sperm is produced
• Testes


  contain interstitial cells, germ cells, sustentacular cells
• Interstitial cells


  secrete testosterone
• Germ cells


  cells that sperm cells arise from
• Sustentacular cells


  nourish germ cells and produce hormones
• Spermatogenesis


  formation of sperm cells

  begins in males at puberty

  interstitial cells increase in number and size

  seminiferous tubules enlarge

  seminiferous tubules produce germ cells and sustentacular cells
• Head (sperm cell structure)


  contain a nucleus and DNA
• Midpiece (sperm cell structure)


  contain mitochondria
• Tail (sperm cell structure)


  flagellum for movement
• Epididymis


  thread-like tubules on side of each testis

  where seminiferous tubules empty new sperm

  where sperm continue to mature and develop the ability to swim and bind to oocytes
• Ductus deferens/ Vas deferens


  extends from epididymis and joins seminal vesicle

  cut during a vasectomy
• Seminal vesicle


  Sac shaped gland near the ampulla of each ductus deferens
• Ducts from the seminal vesicle and the ampulla of the ductus deferens join at the prostate gland to form the ejaculatory duct
• Each ejaculatory duct enters the prostate gland and joins the urethra
• Urethra


  extends from urinary bladder to end of penis

  passageway for urine and male reproductive fluids
• Penis


  Transfers sperm from male to female

  excretes urine
• corpus cavernosum, corpus spongiosum, spongy urethra are 3 columns of erectile tissue which fill with blood for erection
• distal end of the penis forms a cap, the glans penis
• Urethra opens to the exterior as the external urethral orifice
• Prostate gland


  surrounds urethra

  size of a walnut
• Bulbourethral gland


  small mucus secreting glands near base of prostate gland
• Semen


  mixture of sperm and secretions from glands

  provides a transport medium and nutrients that protect and activate sperm
• 60% of fluid is from seminal vesicles

  30% of fluid is from prostate gland

  5% of fluid is from bulbourethral gland

  5% of fluid is from testes
• Seminal vesicles


  provide fructose

  contain prostaglandins

  contains coagulants