AS: Lecture 6&7

• Asexual Reproduction 


  Does not require sex organs to facilitate the perpetuation of the species
• Asexual Reproduction 


  Unicelllular organisms as well as some species of plants reproduce asexually
• Asexual Reproduction can also be seen in cases of parthenogenetic animals
• Parthenogenesis is an uncommon form of reproduction that occurs when eggs develop into embryos without fertilization by sperm cells.
• Sexual Reproduction


  Male and female sex organs are involved in the process
• Sexual Reproduction 


  the ovum and sperm cells fuse to form a new individual
• ovaries


  primary sex organs of females
• ovaries


  attached by the broad ligament (mesovarium) to the body cavity
• ovaries


  comparable to the male testicle
• ovaries


  the site of gamete production
• Three major functions of the ovaries

  1. Gamete production
  2. Secrete estrogen
  3. Forms the corpus luteum
• Gamete Production 


  Gametes are mature male or female germ cell usually possessing a haploid chromosome set
• Secrete Estrogen

  Reduction of muscle development
• Secrete Estrogen

  Development of mammary glands
• Secrete Estrogen

  development of female reproductive system
• Secrete Estrogen

  formation of female external genetalia
• Secrete Estrogen

  fat deposition on hips and stomach
• Secrete Estrogen

  triggering of heat
• corpus luteum


  -responsible for release of progesterone
• progesterone


  -plays important roles in the menstrual cycle and in maintaining the early stages of pregnancy
• a bovine animal has 20,000 potential eggs per ovary
• a human has around 300,000 potential eggs per ovary
• ova


  -are fully developed at puberty and are not continuously produces as compared to the males
• all species contain 2 functional ovaries except for the hen which only has a left functioning ovary
• Fallopian Tube


  -also known as oviduct
• Fallopian Tube


  -a pair of small tubes leading from the ovaries to the horns of the uterus
• Fallopian Tube


  -reserves the ova during ovulation and it is the site of fertilization
• Fallopian Tube


  -egg travels from ovary to uterine horn in 3-4 days
• infundibulum 


  the funnel shaped portion of the fallopian tube near the ovary
• ampulla 


  the widest and longest part
• isthmus


  the narrowest and thickest part
• uterus

  site of implantation for fertilized eggs
• uterus


  divided into a body and two horns
• bitch 


  long straight horns, short body
• sow


  extremely long horns, short body
• cow 


  long horns with caruncle, short body
• mare


  T-shaped horns with large body
• duplex 


  two wholly separate uteri, with fallopian tube
• animals with a duplex uterus

  marsupials

  • kangaroos
  • koalas

  rodents

  • mice
  • rats
  • guinea pigs

  lagomorphs

  • rabbits
  • hares
• bipartite


  two uteri are separate for the most of their length, but share a single cervix