week 9 Flashcards
what are the 4 development stages of sex organs?
- Genetic Sex (XX, XY)
- Gonads(Testis/Ovaries)
- Sex Organs (Organizing Effects)
- Maturation (Organizing and Activating Effects)
What determines genetic sex?
If a boy child is born it is depended on the sperm.
Every egg has an X sex chromosome; a sperm can have either an X or a Y sex chromosome. If the sperm that fertilizes your egg has an X chromosome, you’ll have a girl; if it has a Y chromosome, your baby will be a boy.
Explain the development of gonads.
0-6 weeks → sex organs are undifferentiated
Undifferentiated gonads
Undifferentiated precursor tissue(rise to the sex organs):
Müllerian ducts (female)
Wolffian ducts (male)
Gonads (testes/ovaries) are the first to be determined
Important for production of sperm/ova and hormones
SRY(sex regsion determone on the Y chromosome) gene on the Y chromosome causes gonads to become testes
explain the Development ofOrganizing Effects of Sex Organs.
Becoming Female:
Müllerian system: The embryonic precursors of the female internal sex organs (fimbriae, fallopian tubes, uterus, inner 2/3 of vagina)
Associtated with the development of the female sex organs
Becoming Male:
Wolffian system: The embryonic precursors of the male internal sex organs (seminal vesicles, epididymis, vas deferens,)
Associtated with the development of the male sex organs
Müllerian & Wolffian are determined by Sex Hormones
what are the organizing effects and activating effects of hormones on to sexual differentiation? (Pre and post natal development)
Organizing effects
Sex hormones during prenatal development determines structure of sex organs and brain.
while the fetus is developing in the womb exposure to certain hormones will determine the structure of the sex organs, wheter Müllerian or Wolffian will be developed
Postnatal development at puberty determines other sexually dimorphic features (e.g., breast development and dropping of testes)
* Long lasting effects, lead to the organizing of the organism
Only occur during a specific sensitive period
Activating effects
Sex hormones activated during postnatal stage, e.g. sperm production, erection and ejaculation, ovulation, sex drive
More short term effects - cyclical
what are 2 steroid hormones?
Androgens = testosterone & dihydrotestosterone
Estrogens = estradiol
Their Actions:
Bind to membrane receptors to exert quick effects
Activate proteins in the cell
Alter expression of chromosomes to turn genes off/on.
What are the organizing effects of sexual development, and when do sexual organs start to differentiate?
Organizing Effects: Determination of internal and external sex organs
7-8 weeks → precursor tissue starts to differentiate, based on which hormones the fetus is exposed to
2 precursor tissue systems:
Mullerian system - female tissue
Wolffian system - male tissue
What are AMH/MIH?
Anti-mullerian hormone (AMH)/ mullerian inhibiting hormone (MIH)
Inhibits Müllerian system
Androgens (testosterone, and metabolite dihydrotestosterone)
Ensures development of Wolffian system
In depth, describe what the “male” and “female” hormones activate and organize.
Testosterone (“male” hormone) Androgen Organizing: facial and body hair, lowers voice, muscular development, genital growth Activating: sex drive, reproduction Estradiol (“female” hormone) Estrogen Organizing: breast development, lining of uterus, body fat deposition, maturation of female genitalia, Activating: sex drive, reproduction
Do females only produce estrogen, and do males only produce androgen?
Both males and females produce both androgen and estrogen
One generated less than the other based on the gonads
(testes - produces more androgens and less estrogen)
(ovary - produces more estrogen and less androgen)
What is considered normal for sex chromosomes for males and females?
Typical”
XX(female) OR XY(male) = Dichotomy
however… there are “shades of gray”
what is XX Male Syndrome?
XX sex-reversal
1/25,000 newborn males
Genetic sex is “female”(XX)
SRY is translocated to X chromosome
Y sequences usually located on the distal tip of the paternal X chromosome, something going on with respect to the sperm that is contributing to the development of the fetus
Male gonads (i.e. testes) are formed b/c the SRY gene is present
Identify with and physically look male
Shorter than average, less hair, gynecomastia, hypogonadal, infertile
They are missing all of the other genetic material that is commonly located on the y chromosome to contribute to these male typical features
What is XXY, Klinefelter Syndrome
1/600 newborn males
Additional X from mother’s egg or father’s sperm
Male newborn with extra X chromosome
Range in presentation of symptoms; later diagnosis
Can be mild to the point they are not diagnosed until teen years
75% never diagnosed, they only end up reaching a diagnosis if let’s say you know they’re trying to conceive
Taller than average, hypogonadal, infertile, abdominal fat, low muscle tone
Additional: metabolic syndrome(elevated adipose tissue - thick waistline, high levels of glucose), autoimmune disorder, autism spectrum
What is Androgen Insensitivity Syndrome (AIS)?
Genetic sex is “male” (XY)
Receptors do not respond to androgens or they do not have enough receptors to respond to androgens
AIS can range from complete (external genitalia feminized) to partial (partial genitalia masculinized) to mild (masculinized)
Internal testes/No ovaries or uterus
Hypogonadal – Shallow vagina
Infertile
What is Persistent Mullerian Duct Syndrome?
Genetic sex XY
Extremely rare (prevalence unknown; 250 reported cases in medical literature)
Failure to produce AMH or no receptors for the hormone
Genetic variation in AMH gene –inherited autosomal recessive gene, if you present with two of these recessive genes, then you will present with persistent Mullerian Duct Syndrome
Present with female and male internal sex organs
Both Mullerian system & Wolffian system develop
Undescended testes
Underdeveloped uterus
Hermaphroditism
Infertile
