Lecture 14- CTO
What are primary sex characteristics? - answer Capacity of the reproductive gland
Gonads= overies or testes
Gametes= eggs or sperm
What are secondary sex characteristics? - answer Sexual dimorphism
Distinct difference in size or appearance between the sexes of an animal in addition to
the sexual organs themselves
What is the steps in mammal sex determination? - answerA genetic signal instructing
male of female gonad formation
Once gonads determined they control development of secondary sex characteristics
Sry (sex determining region Y chromosome ) is a transcription factor only expressed
from the Y chromosome
Is gonads are XY they will express Sry which regulates gene expression leading to
testes differentiation
During sex neutral development the mammalian XX or XY embryo both have 'male' and
'female' structures
Male Wolffian duct (precursor of vas dererens)
Female Müllerian duct (precursor of oviduct)
Male determination in XY? - answerThe Sry signal from the Y chromosome causes the
gonads to become testes (not ovaries) and 'male' structures to persist and the 'female'
structures to disappear
XY testes secrete male hormones which act on distant target cells. What are the
hormones? - answerMullerian-inhibiting substance inhibits Müllerian duct (oviduct)
Testosterone signals to the wolffian duct to develop into vas deferens which will carry
sperm
What are primary sex characteristics? - answer Capacity of the reproductive gland
Gonads= overies or testes
Gametes= eggs or sperm
What are secondary sex characteristics? - answer Sexual dimorphism
Distinct difference in size or appearance between the sexes of an animal in addition to
the sexual organs themselves
What is the steps in mammal sex determination? - answerA genetic signal instructing
male of female gonad formation
Once gonads determined they control development of secondary sex characteristics
Sry (sex determining region Y chromosome ) is a transcription factor only expressed
from the Y chromosome
Is gonads are XY they will express Sry which regulates gene expression leading to
testes differentiation
During sex neutral development the mammalian XX or XY embryo both have 'male' and
'female' structures
Male Wolffian duct (precursor of vas dererens)
Female Müllerian duct (precursor of oviduct)
Male determination in XY? - answerThe Sry signal from the Y chromosome causes the
gonads to become testes (not ovaries) and 'male' structures to persist and the 'female'
structures to disappear
XY testes secrete male hormones which act on distant target cells. What are the
hormones? - answerMullerian-inhibiting substance inhibits Müllerian duct (oviduct)
Testosterone signals to the wolffian duct to develop into vas deferens which will carry
sperm
