Human reproduction by Maria


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Human reproduction by Maria

  1. 1. Unit 4 humanreproduction María Boizas Crespo
  2. 2. Human reproduction Living things create other living things in the process of reproduction. Human beings reproduce through sexual reproduction , bringing male and female sex cells together.
  3. 3. Primary sexual characteristis The reproductive systems are the primary sexual characteristics.We already have them when we are born and they are different for male and female.
  4. 4. Secondary sexual characteristics The external characteristics wich differentiate men from women are called secondary sexual characteristics. During puberty,between the ages of eleven and fifteen,the reproductive system matures.
  5. 5. Changes during puberty Some changes are the same for both sexes like:  Growing taller.  Hair growing in the armpit. Other changes are specific to each sex:  Girlsdevelop breasts and their hips get wider.  Boys get deeper voices.
  6. 6. The reproductive cells:sperm Sperm are the male reproductive cells.They have a head and a long tail called a flagellum.They are produced in large numbers from the time of puberty.
  7. 7. The reproductive cells:ova Ova are the female reproductive cells.They do not move.from puberty,an ovum matures every month.
  8. 8. The female reproductive system The female reproductive system is made up of these organs:  The ovaries produce the ova.  The uterus is where the baby develops.  The fallopian tubes conects the ovaries to the uterus.  The vagina conects the uterus to the outside of the body.  The vulva is the external part of the female reproductive system.
  9. 9. The male reproductive system The male reproductive system is made up of these organs:  The testicles are outside the body.They produce sperm.They are covered by a bag of skin called scrotum.  The vas deferens take the sperm from the testicles to the urethra.  The urethra takes the sperm outside the body.  The seminal vesicles and prostate produce seminal fluid and send it to the urethra.  The penis is outside the male reproductive system.
  10. 10. Pregnancy (I) Pregnancy lasts about 9 months and ends in a birth. During the early stage different structures are created to protect the embryo:  The placenta takes nutrients from the mothers blood to the embryo.  The umbilical cord connects the placenta to the embryo.  The amniotic sac protects the
  11. 11. Pregnancy (II) The baby develops step by step:  After 3 months: The embryo has all its organs.It becomes a foetus.  After 5 months: The baby’s body develops and it starts moving and the mother feels it.  After 5 months: The baby is ready to be born and it weighs around 3 kilos.
  12. 12. Labour The process of giving birth is called labour. Labour takes place in three phases:  Dilation:rhytmic contractions make the opening of the vagina and vulva big enough for the baby to come out.  Expulsion:the baby is born and the doctor cuts the umbilical cord.  After birth:the placenta comes out of the mother’s body.
  13. 13. The end