role of chromosomes and hormones Flashcards
define chromosomes
found in the nucleus of cells
carry information in the form of genes
23rd pair of chromosomes determine biological sex
define hormone
a biochemical substance that circulates in the blood but only affect target organs. They are produced in large quantities but disappear quickly
define testosterone
a hormone from the androgen group that is produced mainly in the male testes. associated with aggressiveness
define oestrogen
primary female hormone, playing an important part in the menstrual cycle and reproductive system
define oxytocin
hormone which causes contraction of the uterus during labour and stimulates lactation
how many chromosomes are there in the body
46
(23 pairs)
what are the sex chromosomes for females
XX
what are the sex chromosomes for males
XY
what is a baby’s sex determined by
the sperm that fertilises the egg
if the biological sex of a baby is female what chromosome does the sperm carry
GIRL - sperm carries X chromosome
if the biological sex of a baby is male what chromosomes does the sperm carry
BOY - sperm carries Y chromosome
what gene does the Y chromosome carry that results in the formation of testes
Y chromosome carries a gene called the “sex determining region”
this gene causes testes to develop in an XY embryo (males)
define androgens
male sex hormones
what do hormones do at puberty
a burst of hormonal activity triggers secondary characteristics
if a genetic male produces no testosterone in foetal development, what happens to the development of male sex organs
no testosterone produced in foetal development = no male sex organs
