Ch. 8 Ovigenesis and Fertilization

oogenesis

formation and maturation of female gametes

when does oogenesis start

prenatal stages

oogonia multiply by

mitosis until near birth

two stages of meiotic divisions

meiosis 1 and meiosis 2

meiosis 1

arrested (stop developing) at late prophase

dictyate oocyte

arrested oocyte

no oocyte

mature before puberty

growth and maturation occurs

in cycles after puberty

only oocytes in dominant follicles

mature

follicular development occurs in

waves/cohorts

The zona pellucida develops when 

when oocytes grows 

zona pellucida

outer membrane of the follicle

what hormone is produced by the mature follicle

estrogen

1st follicle, secondary follicle, tertiary follicle, graffian follicle

antrum forms as

dominant follicles emerge

ovulation is induced by what hormone

LH

meiosis 2 is arrested at 

metaphase 

meiosis 2 only occurs of

fertilization occurs

meiosis 1 yields

secondary oocyte and 1st polar body

meiosis 1 occurs before

ovulation

Ater Estrogen triggers LH what happens to oocytes in Meiosis 1

oocytes are freed into follicular fluid and meiosis 1 resumes

how long does it take for oogenesis to complete

anywhere between 12 to 50 years on cyclic basis from puberty to menopause

each primary oocyte yields how many ovum and polar bodies

1 cytoplasm rich ovum and 3 cytoplasm poor polar bodies that disintegrate

Meiosis 1 occurs in what phase

prophase 1

What phase does meiosis 2 occur

Metaphase

What causes follicles to develop

LH

Proteolytic enzymes do what

Weaken the follicular walls

Ovulation results in

The release of the secondary oocyte, follicular fluids, and cumulus cells

Stigma occurs where

Rupture site

An oocyte moves where

Down the oviduct to ampullary-isthmic junction for fertilization

Peristalsis

Muscle contraction

What slows down and hastens transport

Estrogen slows transport

Progesterone hastens transport

Where do sperm transport

Bovine uterus and oviduct (4-16hrs)

First barrier

Cervix that filter dead sperm

Second barrier to the AI junction

Uterotubal junction

Filter sperm and serve as a reservoir for slow continuous release

Lower isthmus

Hormones that speed sperm transport

Prostaglandin and estrogen

Fertilization occurs in

The ampullary-isthmic junction

The site of fertilization

Oviduct

Fertilization

Formaction of zygote

Enzymes of sperm head allow

For penetration of cumulus and corona radiata cells

What facilitate enzymatic activity

Capacitation and acrosome

Sperm head sticks to

The zone pellucida

What allows zona pellucida penetration

Acrosome enzymes

Zona reaction

Prevents other sperm from crossing the zone pellucida

During fertilization sperm enters

The vitelliene membrane by phagocytosis

The second block against other sperm participating in fertilization

Vitelline block

When meiosis 2 resumes what happens

The 2nd polar body is extruded and the female pronucleus forms

Sperm looses its tail and the male pronucleus forms

Syngamy

Merging of pronucleus during fertilization

What happens for fertilization to be complete

Zygote

Polyspermy

Fertilization by 2 or more sperm that results in embryo loss and occurs in heated or aged secondary oocytes

The two barriers to polyspermy

Zona rection and vitelline block

zygote

one cell embryo

spontaneous vs reflex ovulation

spontaneous- ovulating whether they are mating or not

reflex- ovulating only when they mate

cows do not ovulate until…

they are out of estrus