L7 Flashcards
Define gender
“the concept held by an individual (or those raising the individual) that they are male, female or ambivalent
Contrast genetic sex, gonadal sex, and phenotypic sex
- Genetic sex: chromosomal lvl e.g. 46, XX; 46XY
- Gonadal: individuals sex organs (determined base don organs that are present) aka primary sex characteristics
- Phenotypic sex: external genitalia aka secondary sex characteristics e.g. breasts
What is SRY
Sex-determining region Y (SRY) AKA testis-determining factor (TDF), is a protein encoded by the SRY gene that is responsible for the initiation of male sex determination in humans.
What is Turner’s Syndrome? Descibre the frequency, symptomology and effects on fertility. How is it detected?
- 45,XO
Frequency: Relatively common sex chromosome abnormality; 1 in 2500 female births
Distinctive physical features:
- Short stature, ptosis, low posterior hairline
Fertility: Most are infertile
Detection:
- No differences in infancy (emerge in childhood)
- FSH surge in newborns indicates ovarian failure
- Estrogen therapy initiated at age ~12
What is Klinefelter Syndrome? Descibre the frequency, symptomology and effects on fertility. How is it detected?
47,XXY
Frequency: Most common sex chromosome abnormality; 1 in 500 male births
- Fewer than 26% are diagnosed
Symptomology:
- No obvious facial dysmorphology
- Tall stature
- Small testes
- Gynecomastia in late puberty
- Broad hips
- Sparse body hair
- Androgen deficiency, low serum T levels
- Elevated gonadotropins
- Azoospermia
- Psychiatric disorders more common
- Recent incentives encourage diagnosis so proper lifelong treatment can be administered
Fertility: 95-99% of males with KS are infertile
What is Tripe X Syndrome? Describe the frequency, symptomology and effects on fertility. How is it detected?
47, XXX
Frequency: Common sex chromosome abnormality; 1 in 1000 female births
-Most undiagnosed
Symptomology:
- May be taller than average
- May result in kidney failure/disorders or seizures (~10%)
- May cause developmental delays (speech, language and motor skills)
- Most often there are no unusual physical features
- Normal sexual development
Fertility: Fertility is normal
TDF absent for >9 weeks = _______
Testicular differentiation factor absent for > 9 weeks = female development
Gonadal development determines phenotype based on
endocrine and paracrine secretions produced by the gonad
Describe gonadal development in fetus
- During the 5th week inside early embryo, primordial germ cells will migrate to urogenital ridges. Primordial germ cells will become ovarian follicles or initiate spermatogenesis.
- The primordial gonad is undifferentiated and can turn into male or female sex organs.
In females, the medulla will regress and the cortex will thickens. The germ cells will differentiate into primary oocytes.
In males, the medulla will expand and the cortex recedes. Germ cells will migrate to cortex and differentiate into spermatogonia (pre sperm cells). Leydig cells will produce T and DHT (important for development of secondary sex characteristics). Sertoli cells will produce anti-Mullerian hormone, important for continuation of male development.
Describe development of internal genitalia
Early in embryogenesis it is an undifferentiated duct system. Initially both wolffian and mullerian tubes are present. As development occurs, one of the structures will be degenerated. Wolffian duct will go on to give rise to male reproductive structures. Mullerian duct will go on to give rise to female reproductive structures.
Males: Leydig cells will produce T and DHT. Androgen production by Leydig cells will promote WOLFFIAN development. Sertoli cells will secrete AMH which promotes degeneration of mullerian tubes that would’ve otherwise formed female structures. Thus development of TESTES, degeneration of MULLERIAN duct, and continued development of WOFFIAN duct.
Females: Differentiation into OVARIES, degeneration of WOLFFIAN duct, continued development of MULLERIAN
What is androgen receptor deficiency and associated problems?
DISORDER W/SEXUAL DEVELOPMENT (INTERSEX) that results in the partial or complete inability of the cell to respond to androgens. No problem with production of androgen but problem with androgen receptor.
- Leads to incomplete development of BOTH male and female structures. Wolffian and mullerian structures degenerate and there is female external genitalia.
Discuss the contributions of endocrinologist Alfred Jost
Showed in rabbits that develop of female genitalia/reproductive structures is developed in absence of SRY and AMH (required to get mullerian duct degeneration and wolffian development).
Results of early castration in rabbits?
Early castration in males: MULLERIAN development
Early castration in females: MULLERIAN development
Unilateral early castration in males: One side with testes and wolffian development, other side with mullerian duct development
Early castration in males and testosterone: Both mullerian and wolffian development
Testosterone-treated females: Ovaries, wolffian and mullerian duct development
Using a flow diagram, show the normal sex development in genetic males 46, XY and genetic females 46, XX
Slide 11
Describe the development of external genitalia
- External genitlia in the undifferentiated state is called cloaca (week 4). Cloaca go on to become both urinary and reproductive structures.
- VESICLE of cloaca go on to become URINARY BLADDER.
- PELVIC region: in females = URETHRA and in males, PROSTATIC URETHRA
- PHALLIC REGION: in females = vagina, in males = penile urethra (part of urethra that passes thru glans penis).
