Puberty Flashcards
What are the 3 types of “sex”
Genetic- XX or XY
Gonadal- do you have testes or ovaries
Phenotypic- do you have a penis or labia
What part of the Y chromosome turns you into a boy
The SRY (Sex-determing Region of the Y). It makes TDF (Testis Determining Factor) which promotes testis differentiation
How many X chromosomes are necessary for ovarian development/
Two
What causes the undifferentiated gonads to developinto ovaries
The absence of TDF
What are the two ducts that undifferentiated reproductive organs have?
Wolffian ducts- become male reproductive tract (epididymis, vas deferens, etc)
Müllerian ducts- become female reproductive tract (Fallopian tubes, uterus)
What causes the Müllerian ducts to degenerate in a baby boy
Anti-mullerian hormone***
What causes the wolffian ducts to degenerate in a baby girl?
Absence of testosterone**
What enzyme converts Testosterone to Dihydrotestosterone (DHT)?
5-α-reductase**
What does DHT do for a developing baby boy
Promotes the development of EXTERNAL genitalia (penis, scrotum)
What causes the Müllerian ducts to develop into Fallopian tubes and a uterus in a baby girl?
The absence of anti-mullerian hormone.
What causes the development of female EXTERNAL genitalia (labia, clitoris)
Absence of testosterone
What are the 3 cell types in testes
Germ cells (spermatogonia)
Sertoli cells (produce anti-mullerian hormone)
Leydig cells (produce testosterone)
What are the 3 cell types in ovaries?
Germ cells (oogonia)
Granulosa cells (produce estradiol)
Theca cells (produce androgens and progesterone)
Can you look at a 5 week old fetus and tell what gender it is?
No, testes develop in week 6 and ovaries develop in week 9
What hormones are needed to cause the development of the female gonads, the reproductive tract, and the eternal genitalia
NONE AT ALL!!!***
What part of the vagina comes from the Müllerian ducts vs the “external” part
Upper 1/3 comes form Müllerian ducts
Lower 2/3 is the “external” genitalia
What will happen if a developing baby girl is exposed to high levels of androgens in utero?
External genitalia will differentiate into a male-like phenotype!***
What is Congenital Adrenal Hyperplasia aka 21-hydroxylase deficiency aka Virilixed X syndrome?
No 21-hydroxylase enzyme
No aldosterone or cortisol
Excessive ACTH results in the adrenal cortex eating huge and making excessive androgens
Individuals are XX with ovaries and female internal genitalia
Female external genitalia develop but VIRILIZE= clitoris grows to look like a penis, and labial folds appear to be an empty scrotum
Life threatening adrenal insufficiency
What is the most common cause of genital ambiguity
Congenital adrenal hyperplasia/21-hydroxylase deficiency
What do people with congenital adrenal hyperplasia/21-hydroxylase deficiency look like
XX with ovaries, uterus, Fallopian tubes and top 1/3 of vagina
External genitalia is female, but viralized. Big clitoris, labia looks like scrotum
Acne
Hirsutism 🧔🏻
What happens if an XY person lacked the SRY gene?
No gonads
Develops as female
What happens if an XX person gets a translocation of the SRY gene
Testes
Develops as male
What happens if an XY person has defective AMH production or action
Testes
Male and female internal genitalia (wolffian and Müllerian ducts develop)
Male external genitalia
What happens if someone is XY with no testosterone production/action?
Testes
No internal genitalia
Female external genitalia
What would happen in 5α-reductase deficiency?
Testes
Male internal genitalia
Female external genitalia
(Male pseudohermaphroditism)
testosterone not converted into DHT
*******she really talked about this one a lot
What laboratory findings would you see with Complete Androgen Insensitivity Syndrome? Testosterone DHT FSH and Inhibin LH AMH XX or XY? Ultrasound: Genetic skin fibroblast biopsy
Testosterone: high
DHT: normal
FSH and Inhibin: normal
LH: high
AMH: high (must mean there are testes..)
XX or XY? XY
Ultrasound: no ovaries/uterus. Male testes
Genetic skin fibroblast biopsy: absence of binding affinity of testosterone to androgen receptors
External appearance is normal female
What causes peopel with Complete Androgen Insensitivy syndrome to have NO internal genitalia?
They have testes that secrete AMH and testosterone (but the testosterone is not doing anything to support the Wolffian ducts)
Both wolffian and Müllerian ducts regress
Female external genitalia develop, but have a blind ended vagina, and testes
Is complete Androgen insensitivity syndrome comepletely black and white?
No there are variants. May be mild, partial or complete
What is the treatment for Complete Androgen Insensitivity Syndrome?
Gonadectomy
Estrogen replacement therapy
In older ages, FSH and LH are both increased at higher levels than any other time in life. Which one is always higher?
FSH is always higher than LH
during reproductive years, which hormone is higher: LH or FSH
LH is higher
During childhood, which is higher: LH or FSH
FSH is higher than LH
The only time LH is higher is during reproductive years
When are the biggest peaks of GnRH?
Embryonic development
Infancy
Reproductive years in women (monthly cycles)
What marks the start of puberty in boys?
Increasein testicular size (gonadarche) followed by development of pubic hair and penile enlargement
What do boys develop sperm production and ejaculatory capability?
13.5-13.7 years old ***
HAD A RED BOX AROUND IT
What marks the start of puberty in girls?
Thelarche (breast development) Mean age: 10.9 years
When do girls start mensrtuating?
Usually by 13th birthday
Can a girl get pregnant during her first few menstrual cycles?
No!!!**
There is no ovulation for the first few cycles because there is no positive feedback by estrogen**
What is the order of things developing in a girl
Thelarche
Pubarche (pubic hair) 11.2 yrs
Menarche
Adipose in hips
Hips enlarge, pelvic inlet widens
When do girls have their growth spurt
Begins in early puberty and is complete by menarche**
When do boys have their growth spurt?
Begins near the end of puberty, almost 2 years later than in girls*****
What hormone fuses epiphyses in males AND females
Estrogen
What happens to your height if you have EXCESSIVE estrogen during puberty
Shorter stature. (Estrogen fuses epiphyses toward the end of puberty in males and females)
How does puberty affect your dental health
May be the first appearance of periodontal disease due to mouth flora changing
Why are boys taller than girls
Longer time to reach puberty in boys accounts for most of the difference in stature
What causes puberty to begin?
Increase in pulsatile GnRH release that occurs during sleep
Causes MORE LH THAN FSH
*******
LH is stimulated by HIGH pulse frequency
What is the major determinant of pubertal timing?
Genetics
Which is more important than weight in determining timing of puberty?
Body fat percentage ***
Fat kids go into puberty earlier
What is the leptin theory for signaling puberty?
Puberty is physically gated by the energy resources of the body.
Leptin (which comes from adipose tissue) may control onset of puberty.
Delayed puberty in female ballet dancers
Accelerated puberty in obese females
What happens when mice can not produce leptin?
They never undergo puberty.
As soon as they are given leptin, all aspects of the reproductive system are stimulated and fertility ensues
What is the melatonin theory in regard to signaling puberty to start?
Melatonin inhibits GnRH release***
Puberty may be initiated by a reduction in melatonin secretion
LH and FSH spike ONLY at night time during puberty, which makes us think melatonin may be related
LH is higher than FSH ONLY during ______________
Reproductive years
What is precocious puberty?
Development of secondary sexual characteristics before age 8 in girls or 9 in boys
What are the 2 types of precocious puberty?
Gonadotropin-dependent
Gonadotropin-independent
What is gonadotropin-dependent precocious puberty?
🧠Increased gonadotropins (LH, FSH) cause an early onset of puberty
Can be idiopathic or caused by brain tumor
What is gonadotropin-independent precocious puberty?
Gonadotropons are normal, but gonadal hormones are increased.
Due to androgen secreting tumors in testes or estrogen secreting tumors in ovaries 🥚🥚
How do you treat gonadotropin-dependent precocious puberty?
Long-acting GnRH agonists****
Occupies the receptors, causes an initial release of FSH and LH, followed by down-regulation and desensitization
Do boys are girls get gonadotropin-dependent precocious puberty more often
Girls 5x more
What is the treatment for gonadotropin-independent precocious puberty?
Surgical tumor removal
What is delayed puberty?
Lack of physical maturation 2 standard deviations beyond the mean onset
What are the 2 types of delayed puberty
Hypogonadotropic hypogonadism
Hypergonadotropic hypogonadism
What is hypogonadotropic hypogonadism?
Gonadotropin deficiency***🧠
Deficiency of pulsatile release of gonadotropins
A cause of Kallman’s syndrome
*******
What is hypergonadotropic hypogonadism?
Low gonadal hormones result in high gonadotropins due to lack of negative feedback
Streaked gonads
Cause Turners and Klinefelters
***
What is Kallman’s syndrome?
No GnRH neurons in hypothalamus= no puberty
Associated with ansomia due to a genesis of the olfactory bulb👃
No puberty
Can’t smell anything
Short stature
Kallman’s syndrome
How do you treat Kallman’s syndrome?
Supplemental sex-steroid (estrogen or testosterone) and then GnRH later for reproductive capability
What is Turner’s syndrome
Person is XO
Female genital tract and external genitals but NO FUNCTIONAL GONADS
=no negative feedback so LH and FSH will be HIGH
Amenorrhea
How do you treat Turners Syndrome
Give GH first for height, then supplemental sex steroids for secondary sex characteristics
Female genitalia and genital tract
No functional gonads
Short stature
No/late puberty
Amenorrhea
Turner’s Syndrome XO
What is Klinefelter’s syndrome?
47, XXY male
Primary testicular failure=no negative feedback
Feminization occurs 💄
May have germ cell tumors, breast cancer, and osteoporosis
What is the MOST common form of primary testicular failure?
Klinefelter’s Syndrome
***
How do you treat Klinefelters Syndrome?
GH first, then supplemental sex steroids
How do you solve the test problems of pubertal disorders?
- Is puberty delayed/precocious? Will tell you if gonadal hormones are high or low
- Are there normal levels of gonadotropins?
Gonadotropin-dependent precocious puberty
LH/FSH levels:
Gonadal hormone levels:
LH/FSH: increased
Gonadal hormones: increased
Gonadotropin-independent precocious puberty
LH/FSH levels:
Gonadal hormone levels:
LH/FSH: normal
Gonadal: high
Hypogonadotropic Hypogonadism
LH/FSH levels:
Gonadal hormones:
LH/FSH: low
Gonadal hormones: low
(Delayed puberty)
Hypergonadotropic hypogonadism
LH/FSH levels:
Gonadal hormones:
LH/FS: high
Gonadal hormones: low
(Delayed puberty)
