Oogenesis begins in the ___ of the ___ ___ birth, but the final development of ___ is only completed in ___.
ovaries | fetus | before | oocytes | adult life
uterus | fetus | before | ova | puberty
ovaries | embryo | after | oocytes | adult life
oviduct | fetus | after | oogonium | fertilisation
The ___ which lines the ___ surface of the ___, ___ by ___ cell division to form numerous ___.
germinal epithelium | outer | ovary | divides | mitotic | oogonia
sertoli cells | outer | uterus | divides | mitotic | ova
germinal epithelium | inner | ovary | multiplies | nuclear | oogonia
primary follicle | inner | oviduct | divides | nuclear | oocytes
These cells migrate into the ___ of the ___, where they grow and ___ to form ___, and each of these then becomes surrounded by layers of ___ cells and the whole structure is called a ___.
connective tissue | ovary | enlarge | oocytes | follicle | primary follicle
connective tissue | ovary | enlarge | ova | follicle | secondary follicle
muscle tissue | ovary | diminish | oocytes | nutritive | primary follicle
muscle tissue | uterus | explode | oogonia | follicle | primary follicle
By ___, production of ___ in the ___ ceases and by this stage there are several million in each ___.
mid-preganancy | oogonia | fetus | ovary
mid-pregnancy | ova | fetus | oviduct
the end of the preganancy | oogonia | embryo | ovary
the end of fertilisation | oooocytes | fetus | uterus
Very ___ ___ ___, which is a process that ___.
many | oogonia | degenerate | continues throughout life
few | oogonia | regenerate | end after fertilisation
many | ova | are lost | continues until puberty
few | oocytes | die | continues only throughout childhood
At the onset of ___ about ___ ___ remain and ___ than 1% of these ___ will complete their development; the remainder ___ become ___ or ___.
puberty | 250 000 | primary oocytes | less | follicles | never | secondary oocytes | ova
adult life | 50 000 | oogonia | less | follicles | never | secondary oocytes | primary oocytes
puberty | 200 000 | secondary oocytes | more | follicles | always | secondary oocytes | ooogonia
adult life | 25000 | primary oocytes | more | follicles | never | primary oocytes | ova
Between ___ and the cessation of ___ at ___, ___ begin to develop further and several start to grow each ___, but usually ___.
puberty | ovulation | menopause | primary follicles | month | only one matures
fertilisation | oogenesis | puberty | secondary follicles | month | only two mature
puberty | oogenesis | fertilisation | primary follicles | year | only one matures
gametogenesis | ovulation | menopause | secondary follicles | month | only a few mature
Development of ___ follicles involves ___ enlargement, and at the same time they move to the ___ part of the ___ and then undergo ___.
primary | progressive| outer | ovary | meiosis I
secondary | progressive | outer | uterus | meiosis I
primary | systematic | inner | ovary | meiosis II
secondary | chemical | inner | uterus | meiosis II
In ___ the ___ division of the ___ follicle is ___ and forms a ___ and a ___.
meiosis I | cytoplasmic | primary follicle | unequal | tiny polar body | secondary oocyte
meiosis II | cytoplasmic | secondary follicle | unequal | large polar body | ova
meiosis I | mitotic | primary follicle | unequal | tiny polar body | primary oocyte
meiosis I | cytoplasmic | secondary follicle | equal | tiny polar bear | secondary oocyte
After meiosis I, meiosis II begins ___.
but it doesn't go to completion
but it goes round twice
but it often breaks down before completion
and it goes to completion
In its uncompleted condition, the ___ which is still a ___ is ___ from the ___ ( ___ ) by ___ of the ___.
egg cell | secondary oocyte | released | ovary | ovulation | rupture | follicle wall
primary follicle | secondary oocyte | released | oviduct | ovulation | poor quality | follicle wall
egg cell | tiny polar body | released | uterus | ovulation | rupture | ovary wall
ovum | secondary oocyte | dropped | ovary | ovulation | break down | cell wall
___ occurs from one of the two ___ about ___ every __ days; meanwhile the remains of the ___ immediately develop into the yellow body, the ___ which is an additional but temporary ___ with a role to play if fertilisation occurs.
Ovulation | ovaries | once | 28 | primary follicle | corpus luteum | endocrine gland
Fertilisation | ovaries | once | 8 | primary follicle | corpus leutenant | exocrine gland
Ovulation | ovaries | twice | 28 | secondary follicle | corpus luteum | hindrance
Ovulation | uterus | once | 27 | primary follicle | gorgeous luteum | endocrine gland
Highlight the steps of oogenesis:
Oogonia formed in the embryonic ovaries, long before birth and become surrounded by follicle cells, forming tiny primary follicles and remain dormant within ovary cortex.
From puberty a few primary oocytes undergo meiosis I to become secondary oocytes each month but only one of these secondary oocytes surrounded by enlarged follicle, forms a graffian follicle and the others degenerate.
One ovum is formed from each oogonium (the polar bodies degenerate too) and the Graffian follicle releases secondary oocyte into oviduct at ovulation.
Meiosis II reaches prophase and then stops until a male nucleus enters the secondary oocyte, triggering completion of meiosis II.
Fertilised ovum is non-motile and becomes lodged in the endometrium of the uterus where cell divisions lead to embryo formation.
Oogonia formed in the time of puberty, throughout adult life and all oogonia develop into ova, nurtured by the nutritive cells of the seminiferous tubules of the ovaries.
Millions of primary oocytes are formed daily.
Four ova are formed from each oogonium and the Graffian follicle releases secondary oocyte into oviduct by ejaculation.
Meiosis I and II go to completion during oogenesis.
Fertilised ova are small, mobile gametes.