Lecture 13: 79 - Reproduction 1 Flashcards
What determines the following:
- Genetic sex
- Gonadal sex
- Genital sex
- Gender sex (behavioral)
- Genetic sex
- identified by karyotype (XX or XY) - Gonadal sex
(set by gene expression - testes or ovaries) - Genital sex
- external genitalia set by HORMONES - Gender sex (behavioral)
- genotype, phenotype hormones, rearing cues, psycho-social factors
What region of the Y chromosome determines whether testes develop?
What hormone carries the androgen receptor?
What does ovary development depend on?
What are some examples of chromosomal abnormalities?
- Sry
-XY mice with no functional Sry develop ovaries
XX mice with added Sry develop testis - X Chromosome
- 2 X and no Y
- Loss of one X chromosome results in ovarian dysgenesis but not loss of female ducts or genitalia - Aneuploidy (XXY), Mosaicism (different genetic makeup), Chimerism (2 embryos fuse w/ different genetic makeup), Structural Errors (the mouse - one part of the chromosome breaks off and goes somewhere else)
- Differentiate between mitosis and meiosis:
Meiosis = haploid gametes
- all different (4)
Mitosis = diploid gametes
- 2 gametes (2n –> 2n) identical
- Mitosis
Involves _____ cells (ex: cut on skin) - Produces ______ daughter cells
- Yes/No exchange of genetic material between homologous chromosomes
MEANWHILE:
Meiosis (only sex organs)
Involves _____ cells
Produces__(haploid/diploid)___ gametes
- SOMATIC (not germ cells)
- identical
- NO exchange
- Sister chromatids of each chromosome split - germ
- haploid
What happens during meiosis 1 and meiosis 2?
Meiosis I: chromosomes duplicate and exchange genetic material.
Results in haploid numbers of duplicated chromosomes
Meiosis II: No duplication of DNA
Daughter cells have haploid (1N) chromosomes… segregation of sex chromasomes provides mechanism of sexual dimorphism.
Females are arrested in prophase until when?
When is meiosis completed? Which phase is it stopped at 2nd?
How many daughter cells in spermatogenesis? Oogenesis?
- Primary oocyte arrested at birth
- until puberty - Upon fertilization with sperm –> stopped at METAPHASE II
- 4 daughter cells per germ cell in spermatogenesis, but oogenesis only makes one (plus polar bodies).
Meiosis in Male Gamete:
Spermatogenesis does not begin until ______.
Maturation usually requires how many days?
Normal sperm production requires ______
- puberty
- 60-70 days (continuous)
- Production may be 100-200 x 106 /day - reduced temp**
- testes outside the body
In females, loss of one X chromosome results in _______ but not loss of female ducts or genitalia.
ovarian dysgenesis
– still get female ducts & genitalia since the DEFAULT is the female pathway ( maleness is imposed by androgens)
-Ovary development depends on the presence of 2X and no Y chromosome
What does SRY encode?
Where is it found
SRY encodes TDF- testis determining factor
- found on Y chromosome
Define the following:
- Aneuploidy
- Mosaicism
- Chimerism
- Structural Errors
- Aneuploidy (Change in the number of chromosomes)
- Mosaicism (Different genotypes in different cells, arising from the same zygote)
- Chimerism (…arising from different zygotes that fuse during development).
- Structural Errors (e.g. unequal recombination, duplications, inversions)
Why is gonadal sex NOT hormone dependent?
What does it depend on instead?
this can’t be hormone-dependent, since the gonads produce the hormones.
- depends on GENE EXPRESSION
What happens when male hormones are absent? (no androgens?)
What happens in Turner’s syndrome? (XO)
progression to female structures occurs when male hormones are absent.
XO: turner’s syndrome: gonadal streak – indifferent = NO GONAD AT ALL!
State the what develops from the following in both males and females:
- Germ cell
- Coelomic Epithelium
- Mesenchymal Cells
- Germ cell = spermatogonia or oogonia
- Coelomic Epithelium: sertoli or granulosa
- Mesenchymal cells:
- LEYDIG & theca
What is the purpose of the following in males and females: (and which cells do they develop from)
- Sertoli or Granulosa cells
- Leydig & Theca Cells
- develop from Coelomic Epithelium:
- supporting cells that hold it & provide nutrition - Mesenchymal cells:
- hormone factory making testosterone or estrogen
Which cells make anti-mullerian hormone?
Which cells make androgens? (testosterone & DHT?
- Sertoli cells = antimullerian
2. Leydig = make testosterone & DHT
State the important points of the following:
- Primordial germ cells
- Primordial gonad
- Development of testis
- Primordial germ cells – migrate to gonadal ridge
- Primordial gonad – bipotential for testis or ovary (one way or the other)
- Germ cells direct the specific development of the gonad
- Development of testis – is not hormone dependent (medulla)
State the important points of the following:
- Development of medulla (XY)
- Development of ovary (cortex)
- Development of cortex (XX):
- Development of medulla (XY): Seminiferous tubules, Spermatogonia, Sertoli cells, Leydig cells
- Development of ovary (cortex) – is not hormone dependent
- Development of cortex (XX): Secondary sex cords, Oogonia, Theca cells, Granulosa cells
XY Medulla develops into what?
XX cortex develops into what?
Male = medulla
XY- medulla develops into 1) seminiferous tubules
2) spermatogonia
3) sertoli cells
4) leydig cells
XX- cortex develops into
1) secondary sex cords
2) oogonia
3) theca cells
4) granulosa cells.
Development of pubis hair requires what?
Developmental strategy – differentiation obeys _____ program if maleness is not imposed.
Sexual dimorphism is due to differences in the _____ of individual hormones and patterns of secretion.
ANDROGENS
feminine
- amounts
- There are no exclusive female or male hormones – both sexes have similar hormones and receptors.(AMOUNTS are important)
What is important for wolfing duct development?
What about degradation of malarian ducts?
What structure specifically determines the presence of mullein duct growth or wolfing ducts?
What happens when a female is treated with testosterone?
- testosterone
- Antimullerian hormone
- TESTES
- Antimullerian hormone causes degradation of mullerian ducts (produced by testes) WITHOUT TESTES = get mullerian ducts - Treat a female with testosterone - end up with BOTH