endo sex differentiation

• What is the primary focus of the learning objectives in sex differentiation?

  Understanding the role genes and hormones play in sex differentiation during development
• What are the two types of variables that differentiate sex and gender?


  Sex (biological variables) and Gender (social/cultural variables)
• What are the different types of sex determination?

  • Genetic Sex
  • Hormonal Sex
  • Morphological Sex
  • Gonadal Sex
  • Behavioral Sex
  • Physiological Sex
• How do mammals determine genetic sex?

  Mammals use a chromosomal method: XX = female and XY = male
• What is the role of the SRY gene in sex determination?

  The SRY gene on the Y chromosome acts as a master switch for testis development
• What happens to the Y chromosome over time in terms of recombination?

  Y chromosomes can’t do recombination and accumulate mutations
• What is the significance of the bipotential stage in early embryos?

  Early embryos have the potential to form either testes or ovaries
• What is the role of Leydig cells in the testes?

  Leydig cells produce testosterone
• What hormone do Sertoli cells produce?

  Sertoli cells produce Anti-Müllerian Hormone (AMH)
• What are the patterns of testosterone secretion during different life stages?

  • Prenatal: Two surges in testosterone
  • Postnatal: Influences reproductive morphology and behaviors
• What stimulates early testosterone secretion during gestation?

  Testosterone secretion is activated by human chorionic gonadotropin (hCG)
• What is the function of hCG during the first trimester of gestation?

  hCG maintains the pregnancy and stimulates steroidogenesis
• What are the effects of testosterone and AMH on morphological sex differentiation?

  • Testosterone influences internal and external morphological sex differentiation
  • AMH causes regression of the Müllerian duct
• What happens to the Müllerian ducts in the absence of hormones?

  The Müllerian ducts develop into the fallopian tubes, uterus, and cervix
• What is the role of testosterone in the development of the Wolffian duct?

  Testosterone prevents regression of the Wolffian duct, allowing it to develop into male reproductive structures
• Who is Alfred Jost and what was his contribution to fetal endocrinology?

  Alfred Jost was the founder of modern fetal endocrinology
• What did Jost's experiments reveal about the role of hormones in sexual differentiation?

  Jost's experiments showed that testicular hormones maintain the Wolffian duct and regress the Müllerian duct
• What are the expected outcomes of Jost's experiments when gonads are removed prior to differentiation?


  • Wolffian ducts regress in the absence of hormones
  • Testicular hormones maintain Wolffian ducts and regress Müllerian ducts
• What is the role of dihydrotestosterone (DHT) in external morphological sex differentiation?

  DHT is responsible for the development of male external genitalia
• What enzyme converts testosterone to DHT?


  5 α-reductase
• What are the consequences of 5 α-reductase deficiency?

  • Individuals cannot convert testosterone into DHT
  • May present with female genitalia at birth but develop male genitalia at puberty
• What is Congenital Adrenal Hyperplasia (CAH) and its effect on XX individuals?


  CAH is the most prevalent cause of intersex among XX individuals, leading to ambiguous genitalia
• What happens if an XY individual has a mutation in the AMH gene?


  They develop both Wolffian and Müllerian ducts
• What is Androgen Insufficiency Syndrome (AIS) and its effects on XY individuals?


  AIS is the most prevalent cause of intersex among XY individuals, leading to female external anatomy despite having testes
• What are the implications of androgen receptor dysfunction in XY individuals?

  • Testosterone and DHT cannot bind
  • Results in rudimentary (undescended/internal) testes and female external anatomy
• What is the significance of the term "Guevedoces" in relation to sex differentiation?

  It refers to a community where children appear female at birth but develop a penis at puberty
• What is the role of adrenal glands in XX individuals with CAH?


  Adrenal glands lack CYP21A2 and overproduce androgens
• What happens if an XY individual has low levels or no 5 α-reductase?


  They cannot convert testosterone into DHT, leading to female external genitalia until puberty
• What are the effects of adrenal glands overproducing androgens in XX individuals?

  It can lead to the development of male characteristics in XX individuals
• What are the implications of sex differences in the brain?

  • Biological sex influences brain structure and function
  • Social and cultural factors also play a role in shaping gender identity
• What is the HPG axis?

  The HPG axis refers to the hypothalamic-pituitary-gonadal axis involved in regulating reproductive hormones
• What are intersex conditions?

  Intersex conditions are situations where a person is born with reproductive anatomy that doesn't fit typical definitions of female or male
• What is Turner Syndrome?

  Turner Syndrome is a condition characterized by the presence of a single X chromosome (X0)
• What is Klinefelter Syndrome?

  Klinefelter Syndrome is a condition characterized by the presence of an extra X chromosome (XXY)
• What is the Prader orchidometer used for?


  The Prader orchidometer is a tool used to measure testicular volume
• What is Persistent Müllerian Duct Syndrome?


  It is a condition where an XY individual develops both Wolffian and Müllerian ducts due to a mutation in the AMH gene
• What is the significance of 5 α-reductase deficiency?


  It prevents the conversion of testosterone to DHT, affecting external genitalia development
• Who are Caster Semenya and Dutee Chand?

  They are athletes known for their intersex conditions and controversies in sports
• What is the focus of Emily Quinn's talk on being intersex?

  It discusses the misconceptions about biological sex and the experiences of intersex individuals
• What is the significance of sex differences in toys?

  It reflects societal norms and expectations regarding gender roles