S2 Biology - Reproduction

• What does asexual reproduction involve?

  Asexual reproduction involves one parent producing genetically similar offspring
• What does sexual reproduction involve?

  Sexual reproduction involves two parents having sexual intercourse to bring their gametes (sex cells) together in order to produce offspring
• Function of the testes:

  They produce and store sperm. They hang outside the body in the scrotum as sperm production is more effective at lower temperatures than core body temperature
• Function of the Sperm duct:

  The tube that leads from the testes to the urethra
• Function of the Glands:

  These add fluids to the sperm in order to form semen
• Function of the Urethra:

  Tube that leads from the bladder to the tip of the penis. Both urine and semen (which contains sperm) leave the penis through the urethra.
• Function of the Penis:


  Can become erect due to erectile tissue filling with blood to aid intercourse
• Function of the Ovaries:


  They produce and store eggs. Once every 28 days one of the ovaries releases a mature egg
• Function of the Oviduct:

  site of fertilisation. It contains microscopic hairlike cells (cilia) that waft the egg from the ovary towards the uterus. Sperm swim up the oviduct as the egg travels down it
• Function of the Uterus:

  A muscular structure in which a baby can develop. It develops a thick lining every 28 days to provide a site for implantation and placental development. If implantation does not take place the lining is shed as a period.
• Function of the Cervix:

  A narrowing at the base of the uterus between the uterus and the vagina
• Function of the Vagina:

  A muscular tube that is the site of intercourse and also acts as the birth canal
• Ovulation:


  the release of a mature egg by an ovary
• Intercourse:


  The action of releasing the male sex cells within the vagina of the female
• Fertilisation:


  The fusion of the nuclei of the sex cells in the oviduct of the female
• Implantation:

  The fertilised egg (zygote) becomes a ball of cells that burrows into the wall of the uterus in order to gain nutrients to develop further
• Placenta formation:


  The placenta is a structure that brings the embryo's blood into close proximity with the blood within the wall of the uterus. This allows oxygen and soluble food to pass into the embryo's bloodstream. This also allows carbon dioxide and other soluble waste to they've the embryo's bloodstream