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the role of chromosomes and hormones - Coggle Diagram
the role of chromosomes and hormones
The role of chromosomes
everyone has 23 sets of chromosomes - 1 half from mother & 1 half from father
chromosomes carry our DNA which is made up of our genes (which determines our characteristics)
the 23rd pair are what determines your sex - specifically inherited from your father
in the first 6-8 weeks all foetuses have the same undeveloped sex organs
the original system can develop into both male/female sex organs
it is the presence/absence of a single gene (the Sex Determining Region Y or SRY gene) which will dictate the future development of the foetus as male/female.
every foetus develops as a female unless instructed otherwise
the Y chromosome contains instructions for the body to produce
androgens
(male sex hormones)
these cause the embryo to develop along the 'male path'
Male development
SRY gene produce a protein:
Testes Determining Factor (TDF)
TDF influences the development of the gonads, they become testes
the testes produce androgens such as testosterone
testosterone triggers the development of external male organs, i.e., penis
female development
the absence of male hormone will result in the development of the Mullerian system into female sex organs
the role of hormones
most gender development comes from the influence of hormones on
prenatal:
brain development
development of reproductive organs
puberty:
pituitary glands (triggered by hypothalamus) causes gonads to produce a bursts of hormonal activity, which triggers development of secondary sexual characteristics
once testes and ovaries develop they begin to release their own sex hormones:
male hormones are known as
androgens
- the most widely known of which is
testosterone
females hormones are mostly
oestrogen & oxytocin
Testosterone
male hormone, but is present in small quantities in women.
if genetic male produce no/little testosterone during foetal development then no male sex organs appear. if genetic female produces high levels of testosterone during foetal development, male sex organs may appear
high levels of testosterone (evolution) are also linked to aggression because it's adaptive.
aggression towards rivals allows males to compete for opportunity to mate with a fertile female.
Oestrogen
determines female sexual characteristics and menstruation.
alongside physical changes, oestrogen may make women more emotional and irritable during their menstrual cycle
referred to as Premenstrual tension (PMT) or Premenstrual syndrome (PMS).
in extreme case, PMS has be used successfully as a defence in cases of shoplifting & even murder
Oxytocin
Women typically produce more oxytocin that men, particularly as a result of giving birth
hormone stimulates lactation, making it possible for mothers to breastfeed their children.
it also reduces the stress hormone
cortisol
and facilitates bonding, for this reason it has been referred to as the 'love hormone'.
oxytocin released in huge amounts during labour and after childbirth & makes new mothers feel 'in love' with their babies
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