Oogenesis
What is oogenesis?
process where oocytes develop and eventually become competent to contribute to formation of a zygote after fertilization
How long until ovulation occurs after LH surge, and why?
around 27 to 30 hours to give LH surge time to cause follicle to rupture
What are the six follicular layers from outside to inside?
Germinal epithelium, tunica albuginea, theca externa, theca interna, basement membrane, granulosa
What does oocyte maturation coincide with in the cow?
Estrus
What is the maximum number of oocytes occuring after fertilization and before birth?
6-7 million oocyte
What is folliculogenesis?
process where ovarian follicles develop and eventually become eligible for ovulation
Explain oocyte maturation, IN UTERO specifically the different stages and how many chromosomes they have
begins as one primordial germ cell (diploid) - goes through mitosis - becomes two oogonias (diploid) - goes through mitosis - becomes four primary oocytes (diploid) - meiotic prophase begins and DNA replicates - becomes four primary oocytes (tetraploidy) - go into nuclear arrest until puberty
When do granulosa appear and what do they produce?
they appear from very beginning, produce estrogen
How many haploid gametes does one stem cell create after the process of oocyte maturation?
One
How many oocytes are present after birth
2 million
What is oocyte maturation?
prepares the oocyte for fertilization, focuses change on the nucleus and cytoplasm
What happens to the oocyte maturation once puberty starts?
LH surge removes meiotic inhibitors unpausing it, meiosis allowing the tetraploidy primary oocyte to become secondary oocyte (diploid) with first polar body
What is the basement membrane layer of the follicle?
connective tissue
Describe fetal oocyte development in a cow
mitosis then meiosis occurs half way through early on after fertilization, lasting only a short time leaving period of time before birth
How many oocytes are present once puberty starts?
300,000
What is Nuclear maturation?
important to reduce number of maternal copies of chromosomes from four to two, continues to get two to one
What happens to the oocyte maturation after ovulation occurs?
second meiotic division occurs producing second polar body in secondary oocyte (haploid)
Total number of follicles at birth in livestock?
100,000
Describe the fetal oocyte development in a sow
occuring little longer then cow after fertilization mitosis then shortly after meiosis occurs as well for long period of time continue until birth, mitosis stopping shortly after birth and meiosis stopping a little after that
How many between puberty and menopause
around 30 years
What is cytoplasmic maturation?
redistribution of organelles, cytoskeletal, and metabolic alterations, changes in protein synthesis
What happens to the oocyte maturation when fertilization occurs?
when sperm is present, second polar body comes out during fertilization leading to diploid zygote
What is the total number of follicles once puberty occurs in livestock (12 months)
75,000
Describe the fetal oocyte development in mice
mitosis occurring longer than a sow after fertilization, meiosis occurring during the last bit of mitosis lasting after birth
who is the exception of oocyte maturation and fertilization?
dogs and foxes ovulate primary oocyte,