Reproduction 7B

• Fertilisation


  The sperm and egg meet
• Fetus


  Baby from the 9th week of pregnancy until birth
• Sperm

  Male reproductive cell
• Cell division

  1. Cells divide and multiply

  2. Different cells making up the body will develop
• Amniotic sac


  Sac that surrounds the embryo and fetus during pregnancy
• food, water and oxygen are supplied across the placenta from the mother to the embryo
• Placenta

  Organ that provides oxygen and nutrients to the developing baby and removes waste products
• Carbon dioxide and other waste products are removed across the placenta to the mother
• Puberty


  Adolescence
• Sex hormones


  Chemicals that control puberty
• Release of sex hormones

  1. Released by the testes and ovaries

  2. Released by the pituitary gland and the brain
• The foetus is harmed by smoking because the blood of a woman who smokes carries less oxygen then is should, meaning the foetus will not get enough oxygen.
• Main stages of labour

  • The uterus beginning to contract
  • The amniotic breaks.
  • The baby comes out of the vagina.
  • The umbilical cord is cut
  • The placenta detaches and passes through the vagina.
  • The stump of the umbilical cord shrivels and falls off after a week
• Ejaculation


  Semen is forced out of the penis and onto the top of the vagina. This is called….
• Semen


  Sperm cells mixed with special liquids from the glands
• Sexual intercourse in mammals

  Involves the penis and testes of the male and the vagina and ovaries of the female
• Egg cells

  Specifically adapted for their function
• Ovaries


  Produce egg cells or sex cells
• Sperm ducts

  Carry sperm cells from the testes to the urethra in males
• Oviducts

  Carry egg cells from the ovaries to the uterus in females
• 
  

  • Each cycle an egg travels from an ovary through the oviduct to the uterus or womb, where it settles
• Cervix


  An opening between the uterus and vagina that allows sperm in and menstrual blood out
• 
  

  • The scrotum holds the testes, which produce sperm and sex hormones, including testosterone
• Ejaculation takes place inside the vagina

• An egg is waiting

  Sperm might fertilise it and when that happens, the cells begin to divide and multiply and eventually become a fetus
• Sperm swim through the cervix into the uterus
• • During ejaculation, the sperm pass through the sperm duct and combine with seminal fluid produced by the glands to create semen, which exits the body through the penis
• • Ovaries produce the eggs and the hormones that regulate the ovulation cycle
• Gestation and birth

  A fertilised ovum divides to form a ball of cells called an embryo. The embryo attaches to the lining of the uterus. It begins to develop into a fetus and then becomes a baby when it is born. It takes about 40 weeks for a fetus to develop in the uterus. This time is called gestation.

  A)

  B)

  C) Amniotic fluid

  
• The fetus relies upon its mother for:

  • protection against knock and bumps, and temperature changes
  • oxygen for respiration
  • nutrients - food and water
  • removal of waste substances
• The fetus is protected by the uterus and a liquid called amniotic fluid.
• The placenta is an organ responsible for providing oxygen and nutrients, and removing waste substances. It grows into the wall of the uterus and is joined to the fetus by the umbilical cord.
• The mother's blood does not mix with the blood of the fetus, but the placenta lets substances pass between the two blood supplies:

  • oxygen and nutrients diffuse across the placenta from the mother to the fetus
  • carbon dioxide and other waste substances diffuse across the placenta from the fetus to the mother