Role of chromosomes and hormones
Role of chromosomes: chromosomes are made from DNA. 46 chromosomes in
body, 23 pairs with the 23rd pair determining biological sex. The chromosomal
structure for females is XX, for males XY. Normal egg cells have X chromosome,
sperm carry an X or Y chromosome. The baby’s sex is determined by the sperm
that fertilises the egg cell. Female = sperm carries X chromosome. Male =
sperm carries Y chromosome/ Y chromosome carries a gene called SRY, which
causes testes to develop in an XY embryo, these produce androgens (male sex
hormones).
Role of hormones: chromosomes initially determine a person’s sex, but most
gender development comes about through the influence of hormones.
Prenatally in the womb, hormones act upon brain development and cause
development of the reproductive organs. Males and females produce many of
the same hormones but in diff concentrations. Importance in male
development are a no. of hormones called androgens, including testosterone.
Testosterone: controls development of male sex organs during foetal
development – if no production of it, then no male sex organs appear. If a
genetic female produces high levels of it, male sex organs may appear. High
levels of testosterone are linked to aggression because it is adaptive.
Aggression towards rivals allows males to compete for opportunity to mate
with a fertile female.
Oestrogen: female hormone determining female sexual characteristics and
menstruation. Causes some women to experience heightened emotionality
and irritability during their menstrual cycle – referred to as premenstrual
tension PMT, or premenstrual syndrome PMS when these effects become a
diagnosable disorder.
Role of chromosomes: chromosomes are made from DNA. 46 chromosomes in
body, 23 pairs with the 23rd pair determining biological sex. The chromosomal
structure for females is XX, for males XY. Normal egg cells have X chromosome,
sperm carry an X or Y chromosome. The baby’s sex is determined by the sperm
that fertilises the egg cell. Female = sperm carries X chromosome. Male =
sperm carries Y chromosome/ Y chromosome carries a gene called SRY, which
causes testes to develop in an XY embryo, these produce androgens (male sex
hormones).
Role of hormones: chromosomes initially determine a person’s sex, but most
gender development comes about through the influence of hormones.
Prenatally in the womb, hormones act upon brain development and cause
development of the reproductive organs. Males and females produce many of
the same hormones but in diff concentrations. Importance in male
development are a no. of hormones called androgens, including testosterone.
Testosterone: controls development of male sex organs during foetal
development – if no production of it, then no male sex organs appear. If a
genetic female produces high levels of it, male sex organs may appear. High
levels of testosterone are linked to aggression because it is adaptive.
Aggression towards rivals allows males to compete for opportunity to mate
with a fertile female.
Oestrogen: female hormone determining female sexual characteristics and
menstruation. Causes some women to experience heightened emotionality
and irritability during their menstrual cycle – referred to as premenstrual
tension PMT, or premenstrual syndrome PMS when these effects become a
diagnosable disorder.
