Sexual reproduction

• Fertilization


  The fusion of the nuclei of a sperm and egg cell
• Heredity


  The passing down of genetic material from one generation to the next during sexual reproduction
• Humans have 23 pairs of chromosomes, resulting in endless possible combinations
• Puberty

  Involves physical maturation, usually around 11-14 years of age, when the right hormones are produced
• Changes experienced by males and females during puberty

  • Males: Height and weight increase, hair growth, voice deepens, muscle strength increases, production of sperm
  • Females: Hips become broader and rounder, breasts develop, maturation of eggs
• Fertilization

  1. Penis deposits semen containing sperm cells in the vagina

  2. Sperm cells swim through the cervix, into uterus, and into oviduct

  3. Sperm cell meets egg cell in the oviduct

  4. Fertilisation occurs when nucleus of the sperm cell fuses with the nucleus of the egg cell
• Menstrual cycle

  1. Ovaries release an egg cell every 28 days

  2. Uterine lining thickens to prepare for implantation

  3. If no fertilisation occurs, menstruation will occur again after day 28
• Substance abuse (e.g. alcohol, smoking, drugs) can have harmful effects on the foetus, such as premature birth, low birth weight, and underdeveloped organs
• Temporary birth control methods

  • Rhythm method
  • Condom
  • Spermicide
  • Diaphragm
  • Intra-uterine device (IUD)
  • Birth control pills
• Permanent birth control methods

  • Tubal ligation (female)
  • Vasectomy (male)
• Sexually transmitted infections can be transmitted through sexual intercourse, blood transfusion, sharing contaminated needles, and from mother to baby during childbirth or breastfeeding
• Syphilis


  Bacterial infection that can be treated with antibiotics, but can have long-term effects like blindness, paralysis, brain and heart damage, and infertility if left untreated

  symptoms:

  • painless sores
  • red rashes
  • weight and hair loss
  • flue-like symptoms
• Gonorrhoea


  Bacterial infection that can be treated with antibiotics, but can lead to infertility and long-term pelvic/lower abdominal pain if left untreated

  symptoms: burning sensation when urinating

  • discharge of pus
  • lower abdomen pain
• HIV

  Viral infection with no cure, can lead to Acquired Immunodeficiency Syndrome (AIDS) and death if left untreated
• Label from left top to right bottom to right top

  1. Penis
  2. Urethra
  3. testis
  4. Sperm duct
  5. Sex glands

  
• Penis


  Deposits semen into vagina during ejaculation (semen leaving the male

  reproductive system)
• Urethra


  • Tube that allows sperm to pass through during ejaculation
  • Allows urine to be removed from body

  (not at same time)
• Sex glands

  • Produce nutrient fluid to nourish the sperm
  • Sperm + fluid = semen
• Sperm Duct

  Tube that carries sperm from testes to urethra
• Testis


  • Produces sperm
  • Produces male sex hormones (testosterone) that controls sexual development
• Name the parts of a female reproductive system

  A: Ovary

  B: Oviduct / Fallopian tube

  C: Uterus

  D: Cervix

  E: Vagina

  
• The fertile period is on the 10th-15th day after Day 1 of menstruation. the 14th day is ovulation day
• A sperm can survive 3-5days in the female reproductive tract while the egg can only survive 36h
• Rhythm method: refrain from sexual intercourse during fertile period
• Condom: rubber covering prevents sperm from entering vagina and also prevents spread of STI
• Diaphragm: Placed in the vagina to cover cervix and prevent sperm from entering uterus (does not prevent spread of STI)
• Intra-uterine device: lasts 3-10years, prevents sperm from reaching egg and foetus from implanting onto uterus lining
• Birth control pills: disrupts the release of eggs, still menstruating
• STD that have flu-like symptoms:

  • Syphilis
  • Human Immunodeficiency virus
• Reasons for not conceiving even with healthy eggs

  • husband has low sperm count
  • fallopian tube damaged or blocked
  • Not having sexual intercourse during fertile period
• Uterus


  muscular organ where embryo implants and develops into foetus during pregnancy
• Vagina

  Known as birth canal, sperm deposited here
• Oviduct / Fallopian tube


  Where fertilisation takes place
• Egg + sperm > zygote > embryo > foetus
• Every human cell has 23 chromosomes except for sperm, egg cell and red blood cell