WEEK 15: Reproductive System

• Production of gametes

  Males - sperm

  Females - eggs (ova)
• Development and nourishment of a new individual

  female: birth and milk production
• production of reproductive hormones

  gender-specific body form and function
• the reproductive organs in males and females produce gametes by meiosis
• 2 consecutive cell divisions halve the chromosome number from 46 total chromosomes to 23 total chromosomes
• early prophase 1

  the duplicated chromosomes become visible chromatids
• middle prophase 1

  pairs of chromosomes synapse, crossing over may occur at this stage
• metaphase 1

  pairs of chromosomes align along the center of the cell, random assortment of chromosomes occur
• anaphase 1

  chromosomes move apart to opposite sides of the cell
• telophase 1

  new nuclei form, and the cell divides, each cell now has two sets of half the chromosome
• prophase 2

  each chromosome consists of two chromatids
• metaphase 2

  chromosomes align along the center of the cell
• anaphase 2

  chromatids separate, and each is now called a chromosome
• telophase 2

  new nuclei form around the chromosomes, the cells divide to form four daughter cells with half as many chromosomes as the parent cell
• male reproductive system - serves to produce, transport, and introduce mature sperm into the female reproductive tract for fertilization
• external portions of male reproductive system: penis and scrotum
• scrotum - sac containing testes
• dartos and cremaster muscles help regulate testes temperature
• median septum: divides the scrotum, isolating each testicle

  • helps prevent any infection from one testicle to the other
• spermatic cord: contains the sperm duct (vas deferens), blood, lymphatic vessels and nerves
• cremaster muscle: surrounds the spermatic cord and testes
• testes

  • inside the scrotum
  • divided into lobules containing the seminiferous tubules and interstitial cells
  • organs that generate sperm and secrete the male sex hormone called testosterone
• tunica albuginea: thick, dense connective tissue that surrounds each testis
• mediastinum testis: thickening of the tunica albuginea at the posterior surface
• seminiferous tubules: found inside the testicular lobules

  • site of sperm development
  • produces spermatozoa
  • contains: germ cells and sustentacular cells (Sertoli cells)
• interstitial cells (Leydig cells): found enmeshed with the seminiferous tubules, produce the testicular androgens

  • secretes testosterone
• spermatogenesis: sperm formation
• spermatogenesis: sperm formation

  • begins when a male reaches puberty and usually continues throughout life
  • thousands are produced each second
  • 1-2 months maturation
• development of gametes involves a process called meiosis
• 1 germ cell = 4 sperm
• head


  contains the nucleus, which is packed with genetic material. topping the head of the sperm is a cap called an acrosome.
• acrosome


  contains enzymes that help the sperm penetrate the egg during fertilization
• middle piece


  contains numerous mitochondria that supply the sperm with the energy it needs to migrate up the female reproductive tract
• tail

  • flagellum
  • whip-like movements propel the sperm forward
• ductus epididymis

  • Single, highly coiled tube that forms the body and tail of the epididymis.
  • Lined with pseudostratified columnar epithelium
  • Basal lamina has smooth muscle cells which help move spermalong the duct.
  • Surface is covered with stereocilia (long, branched, irregularmicrovilli).
• ductus (vas) deferens

  • Straight tube with a thick, muscular wall
  • Narrow mucosa with longitudinal folds
  • Covering: Pseudostratified columnar epithelium withstereocilia
• penis

  • deposits sperm in the female vagina
  • consists of erectile tissue
  • Three cylindrical masses of erectile tissue:
  • Corpora cavernosa of the penis dorsally
  • Corpus spongiosum ventrally and surrounding the urethra
  • Glans penis the dilatation of the corpus spongiosum at its end
• tunica albuginea


  layer of dense connective tissue that covers the corpora cavernosa
• seminal vesicles

  • Located at the base of the bladder
  • Empty into the ejaculatory duct
  • Lined with cuboidal or pseudostratified columnar epithelium rich in secretory granules
• prostate

  • located below the bladder
  • Consists of glandular and muscular tissue and empties into the urethra.