role of chromosomes and hormones

• role of chromosomes

  made from DNA

  genes are short sections of DNA that determine the characteristics of a living thing

  46 chromosomes into 23 pairs

  23rd pair determines biological sex

  females XX

  males XY

  normal egg cells produced by a human ovary have an X chromosome

  half sperm carry X chromosome and half Y
• hormones

  chemical substance circulated in the blood that controls and regulates the activity in certain cells/organs

  puberty Burt of hormonal activity triggers the development of secondary sexual characteristics

  males and females produce many of the same hormones but different concentrations
• testosterone

  predominantly in males

  influence of testosterone on sexual differentiation of a foetus begins in early pregnancy

  involves internal and external genitalia

  Gonads are sex glands

  by week 8 of gestation they produce hormones
• effects of testosterone

  development of male sex organs

  acts on hypothalamus without this the brain would develop female

  associated with spatial skills

  associated with male type behaviours such as competitiveness and aggressiveness
• oestrogen

  promotes development and maintenance of female characteristics of the body and later menstruation

  small amounts produced in males

  alongside physical changes- development of breasts, oestrogen causes some women to experience heightened emotional skills, irrational behaviour
• Oxytocin

  produced in and outside the brain by both males and females to control key aspects of the reproductive system

  action greater in females as it combines with oestrogen to enhance other effects

  released in massive qualities during labour

  released after childbirth to make new mothers feel in love with their baby and stimulates lactation
• cortisol

  stress hormone

  men produce less
• evaluation

  strengths- David Reimer case study biological effects

  dabs et al found more testosterone in men in prison

  weakness- Tricker et al 43 males given either testosterone or placebo no significant differences found after 10 weeks

  animal studies cannot generalise physiology is different

  overemphasis on nature- arguably bio reductionism