Gametogenesis and Fertilization Flashcards
what are primoridal germ cells and what do they become and what do they become when they migrate to the genital ridge?
progenitors of gametes from yolk sac endoderm. they migrate to genital ridge which will become an indifferent gonad
what are the mullerian ducts?
aka paramesonephric ducts. in females, they develop into fallopian tubes, uterus, and cervix
what do seminiferous cords consist of?
sertoli cells and primorial germ cells (stem cells for spermatogeneis that stay dormant until puberty)
intermediate mesoderm gives rise to ____?
urogenital orans (Leydig cells, Sertoli cells, follicular cells, ovary, testis, ducts, uterus)
urogenital sinus endoderm gibes rise to _____?
terminal internal parts of genital organs (vesicular, prostate and bulbourethral glands)
Mullerian ducts disappear in males under the influence of what hormone?
anti-paramesonpehric hormone
what is scrotal hernia?
congenital weakness of the abdominal wall (type of inguinal hernia)
What is it called when the testis fail to descend into the scrotum?
Cryptorchidism
In gametogenesis, mitosis results in more ___ and ___
more spermatogonia and oogonia
___ and ___ undergo mitosis
spermatocytes and oocytes
what initiates cleavage?
fertilization creating the zygote, restoring DNA complement (2n)
mitosis results in formation of ____
2 daughter cells (diploid)
meiosis results in ____
daughter cells with half the parental number of chromosomes (haploid) AKA gametes
Gametes are haploid or diploid?
haploid (1n)
What are the the goals of meiosis?
reduction of diploids and exchange of genetic material
An exchange of genetic material happens in what phase of meiosis?
prophase of meiosis 1 (crossing over)
crossing over results in ___
4 daughter cells with four different genetic makeups
one primary spermatocyte produces __ sperm
4
what gamete starts as a large cell resulting in small cells?
spermatocyte
1 primary oocyte produces __ ovum and __ polar bodies
1 ovum and 2-3 polar bodies
Primary oocytes (4n) are arrested in meiosis 1 until _____
puberty/ ovulation
where does the secondary oocyte await fertilization?
uterine tube
in oogenesis when is meiosis 2 completed?
on sperm contact
what is the result of oogenesis?
ovum (1n) and 2nd polar body (1n)
At puberty, hormone influence on folliculogenesis leads to ___
ovulation
What kind of follicle contains cumulus oophrous?
Tertiary mature/ Graafian follicle
Which follicles are antral?
secondary =secretory
the zone pellucid forms with what kind of follicle?
primary
which follicles are resting?
primordial
What does the zone pellucida do?
acts as an immunologic protective barrier for the developing egg and early embryo
what follicle contains a primary oocyte with zona pellucida and corona radiata cells?
secondary follicle
liquor folliculi formation begins with what kind of follicle?
secondary/antral
after ovulation, the corpus hemorrhagicum will be replaced by ___
luteal cells to become the corpus luteum
what hormones does the corpus luteum produce?
progesterone and some estrogen
what does progesterone do?
maintain pregnancy, stimulate mammary development, and locally down regulate the immune system
the corpus luteum regresses during what stage?
diestrus
what is the connective tissue scar that remains after regression of the corpus luteum?
corpus albicans (white body)
what is an atretic follicle?
follicle not selected to complete maturation that will undergo apoptosis
the corpus luteum contains what types of cell populations?
theca and granulosa cells
what hormone activates sertoli cells?
FSH
what do sertoli cells secrete?
AMH, inhibin/activins to regulate FSH, ABP
What does androgen binding protein do?
binds testosterone, increase concentrations in the seminiferous tubules and stimulate spermatogenesis
spermatogenesis is very sensitive to _____
temperature, X ray radiation, vitamin A, diseases, stress, and drugs
spermatogonia remain dormant until puberty then proliferate by ___ division
mitotic
where is meiosis completed in spermatogenesis?
testes
Do spermatids divide?
no they undergo metamorphosis
when do oogonia complete their proliferation?
early embryonic stage
females are born with what kind of oocytes?
primary
one oocyte gives rise to how many ova?
1
where is meiosis completed in oogenesis?
salpinx (Fallopian tube)
when does oogenesis stop?
after the ovary is exhausted of germ cells (10-12 years in dogs, 14-16 in cattle, 20-22 yrs in mares)
only ____ sperms can undergo acrosome reactions
capacitated
where does capacitation of sperm occur?
uterine environment
What does the sperm need to digest its way through the zone pellucida?
release of acrosomal enzymes
where does sperm most commonly contact the oocyte?
fallopian tube
what prevents other sperm from penetrating the zona pellucida?
sperm contact with oocyte releases proteases from the cortical granules modifying the zona pellucida, acting as a barrier
what causes the oocyte to complete meiosis 2 ?
calcium wave
what is syngamy?
union of male and female pronuclei entering the first mitotic division
__n = a zygote
2n
Do spermatogonia and oogonia have complete DNA complement?
Yes. Primitive sex cells undergo mitosis
do spermatocytes and oocytes undergo mitosis or meiosis?
meiosis (to give rise to gametes)
what consists of a tertiary follicle?
one antrum containing liquor follicle, eccentric cumulus oophorus, contains primary oocyte
axoneme of cilia/sperm flagella is a derivative of a modified _____
centriole (basal body)
can spermatogenesis continue throughout life?
yes
when does oogenesis stop?
when they ovary is exhausted of primordial follicles
