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.
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.
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.
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.
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.
The reproductive cells:ova Ova are the female reproductive cells.They do not move.from puberty,an ovum matures every month.
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.
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.
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
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.
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.