Histology Female Reproductive System Flashcards
what is proeostrus?
Period where corpus luteum regresses and progesterone declines. Oestrogen predominates and behaviour changes
oestrus
period of sexual receptivity and ovulation occurs during it or slightly after
metoestrus
post ovulatory phase where the corpus luteum develops and progesterone increases
dioestrus
progesterone level is highest, phase of corpus luteum
FSH
stimulates recruitment and growth of follicles
LH
final maturation of follicle and induces ovulation
Oestrogen
induces oestrus and sperm and egg transport and fertilisation
changes in reproductive tract including increased blood flow, growth of epithelial tissue, relaxation of cervix, increased myometrial tone
Progesterone
prevents ovulation and maintains pregnancy
Ovaries consist of
cortex and medulla
EXCEPT MARE
Cortex is covered by a dense layer of
connective tissue called tunica albuginea ovarii
under the epithelium, dense white and fibrous
Cortex consists of
numerous follicles in different stages of development and degeneration, corpora lutea, interstitial cells, stromal connective tissue
stromal cells
resemble smooth muscle cells and are arranged in whorls
highly reactive and capable of phagocytosis and lipid storage
formation of follicle wall
Medulla consists of
loose fibro-elastic tissue, contains convoluted ovarian arteries and veins
smooth muscle cells cells also present conveyed by mesovarium
vestigial rete ovarii may also be found in medulla
What is the epithelium covering the cortex in young animals?
cuboidal to columnar
What is the epithelium covering the cortex in older animals?
Squamous and interrupted at the site of a previous ovulation
It is continuous with the mesothelium of the mesovarium
Mare ovary shape?
bean shaped
Is the mare ovary divided into cortex and medulla?
no
ovulation fossa in the mare
located at free border and covered by columnar epithelium
rest of the mare ovary is covered by
squamous epithelium
Zona vasculosa equivalent in mare?
thick layer under epithelium, free from follicles and consists of convoluted blood vessels, rete ovarii and muscle fibres
Cortex equivalent in mare?
heavy tract of connective tissue with blood vessels continued into interior where follicles are distributed
What is the target organ of LH and FSH?
ovarian cortex
Oogonia or primordial cells on reaching the developing ovary undergo
a period of repeated mitotic division, which in all mammals ceases before or soon after birth
when oogonia enter prophase of the first two meiotic divisions
they become primary oocytes
all of them are formed before puberty
Primary oocyte becomes surrounded by single layer of
epithelial cells and forms a primordial follicle
In ruminants, primordial follicles
are evenly distributed throughout cortex of ovary
In dog and cat, primordial follicles
may contain a no. of oocytes and are known as polyovular follicles
Poly ovular follicles
form when epithelial cells that form the wall of the follicle fail to isolate the members of a germ group into uniovular follicles. Studies suggest they undergo degeneration
The primary oocyte does not complete the prophase of the first meiotic division
but enters prolonged or dictyate state until stimulated to undergo further devlopment or degeneration
primary follicles
primordial follicles undergo further development
Granulosa layer
proliferation of surrounding epithelial cells called granulosa cells forms stratified layer around oocyte
Zona pellucida
non-cellular, glycoprotein positive layer that forms between vitelline membrane of oocyte and granulosa layer
considered to develop from the follicular cells and/or the oocyte
Secondary follicle
towards the end of development of the primary follicle, stromal cells begin to be organised around the multi-laminar primary follicle, and is now termed a secondary follicle, forming an inner theca interna and outer theca externa
Outer theca externa
fibrous connective tissue
concentrically arranged fibres and fusiform cells that do not appear to have a secretory function
inner theca interna
richly vascularised tissue
large spindel-shaped cells, oval nuclei, lipid droplets
enmeshed in a network of reticular fibres
cytological characteristics, secrete androgens under influence of LH
Androgens are aromatised to
oestradiol by granulosa cells
Long projections of the follicular cells
penetrate right through the zona pellucida and make contact with vitelline membrane of oocyte
Cytoplasmic projections of oocyte
also project to follicular cells, but are much shorter
like stumpy microvilli
only penetrating a little way into the zona pellucida
