gritti 18 Flashcards
internal genitalia of the female
ovaries, oviduct, vagina and uterus
where does oogenesis take place?
in the ovaries.
oocytes starts to be produced before birth but then they are arrested in some steps of their meiotic cycle and they complete their second meiotic division only after fertilization
2 main sex hormones produced in the ovaries
progesterone->important for pregnancy
estrogen->for the correct functionality of the female reproductive system
2 layers of the capsule that cover the ovaries
-germinal epithelium: simple cuboidal epithelium
-tunica albuginea: layer of dense connective tissue that supports the epithelium
the ovarian parenchyma is divided in 2 parts
cortex: outermost part, highly cellular connective tissue, where we can find ovarian follicles->in this region we can find oocytes at different maturation stages
medulla:loose connective tissue, vascularized (ovarian arteries and veins), lymph vessels and nerves entering at the hilum
where are positioned primordial follicles in the cortex?
in the outermost part.
as they mature, they go deeper down in the parenchyma
what are ovarian follicles?
sites in which oocytes develop
structure of primordial follicles
-already present before birth
-oocyte arrested in meiotic phase I+one layer of follicular cells (squamous cells around the oocyte)
structure of primary unilaminar/multilaminar primary follicles
in each menstrual cycle after puberty some primordial follicles get activated and develop into primary follicles.
unilaminar:
oocyte+one layer of granulosa cells (developed from follicular cells)
multilaminar:
oocyte+multiple layers of granulosa cells
what is the hormone that dictates this primary maturation step of the primordial follicles?
FSH->follicular stimulating hormone
then granulosa cells will produce other hormones that will help in keeping the primary follicles in their quiescent state
zona pellucida
thin region made of glycoproteins around the oocyte formed by the oocyte itself during the development from primordial to primary follicle
-fundamental for the entrance of the spermatozoa and its binding
-essential to not make entry additional ones
the stromal cells between follicles proliferate during the maturation of the primordial follicles, dividing in two regions:
theca interna cells: producing steroid
theca externa: fibroblasts and smooth muscle cells merging with the surrounding stroma
->supportive role
when can we say that we have a multilaminar primary follicle?
when we have
-oocyte
-multilayer of granulosa cells
-initial differentiation of theca cells
secondary or antral follicle
the granulosa cells of the primary follicle will start to produce a liquid that will form sparse cavities that will merge into a big antrum.
the layer of granulosa cells around the oocyte is called corona radiata.
the part that connects the granulosa layer with the oocyte is called cumulus oophorus
stratum granulosum: multilayer of granulosa cells that surround the antrum->avascular
theca folliculi:
stroma cells divide into theca interna and theca externa
mature or graffian follicle
-terminal step of maturation
-largest antrum
-largest oocyte
-the theca folliculi is well organized
-theca interna: vacuolated cells
-theca externa: fibroblasts and smooth muscle cells (flatten) that merge with the stroma
between the theca interna and the granulosum layer there is a basement membrane
the theca interna cells produce androgens
and the granulosa cells in the stratum granulosum convert them into estrogens
when do we see the appearance of the basement membrane between the theca interna and the granulosa layer?
in the secondary or antral follicle
is the granulosa layer vascular or avascular?
avascular
theca interna and externa show blood vessels
what is the stigma?
a witish ischemic area formed as a consequence of the bulging of the mature follicle with the tunica albuginea
(when the dominant follicle is releasing the oocyte from the ovary during ovulation)
Luteinising hormone
granulosa cells in the mature follicle produce estrogens that stimulate the production of LH.
LH is the key hormone for ovulation
corpus luteum
-what remains after ovulation
-if there is no egg fertilization, the corpus luteum begins to degenerate, infiltration of macrophages that make it become the corpus albicans
-if there is fertilization, we start to produce the human chorionic gonadotropin hormone and the corpus luteum itself becomes a progesterone-secreting structure which helps the progression of the pregnancy
the corpus luteum has to be infiltrated with what to generate the corpus albicans?
collagen and few fibroblasts
athtretic process
the follicles that do not undergo ovulation become athretic
-condensation of nuclear chromatin
-shrinkage of the cytoplasm of follicular cells and of the oocyte
-collapse of the zona pellucida
-thickening of the basal membrane that separate TI from the granulosa layer
-macrophages enter the degenerating structure to clean up the debris
uterine tubes structure
-infundibulum with fimbriae (that helps the trapping of the oocyte from the ovary to the tube)
-ampulla
-isthmus
-intramural (uterine) part
the wall of the oviduct is composed of 3 layers
the mucosa
-simple columnar epithelium with ciliated and non ciliated cells (secretory peg cells with short microvilli)
-lamina prorpia of loose connective tissue
in the infundibulum part there are the fimbriae
->evaginations
thick muscolaris
inner circular and outer longitudinal layer of smooth muscle cells (at least 2 layers can be more)
thin serosa
simple squamous epithelium covered by a thin layer of connective tissue
where can we find the fimbriae?
in the infundibulum
covered by ciliated cells that help the oocyte to enter into the oviduct
where does fertilization occur?
in the ampulla of the uterine tube
the lumen of the ampulla is almost fully filled with mucosa foldings
as we reach the isthmus the ampulla’s lumen gets smaller and smaller
which cells can we find in the epithelium of the isthmus of the uterine tube?
ciliated cells and secretory peg cells (non ciliated with short microvilli)
ciliated cells decrease in number the isthmus
where can we see an enrichment of the muscular layer in the uterine tubes?
as we get closer to the uterus, towards the isthmus.
- the smooth muscle will increase proportionally form the infundibulum as we go towards the uterus
the uterus is composed of 3 parts
fundus
body
cervix
3 layers of the uterine wall
endometrium=mucosa
simple columnar ciliated secretory cells
lamina propria: type III collagen fibers (non bundled) with abundant fibroblasts and ground substance
characterised by branched tubular glands across the whole endometrium
myometrium: thick muscle layer
3 layers not distinguishable one from the other
highly vascularized
the part that during preparation for pregnancy increases in size (hypertrophy) and in cell number (hyperplasia)
perimetrium: loose connective tissue and mesothelium /adventitia in some areas->continuous with ligaments
the endometrium is divided in 2 layers
-stratum functionale
most superficial one, full of vessels, the one that collapse at each menstrual cycle
stratum basale: it is retained during each menstrual cycle, it serves fort the regeneration of the stratum functional
is the basal layer affected by the loss of blood in the functional layer during each menstrual cycle?
no, because they have different blood supplies.
the basal layer is supplied by straight arteries, the functional by spiral arteries and terminal capillaries that arise from spiral arteries
where are arcuate arteries in the uterus? in which layer?
in the myometrium
6-10 branches of the uterine artery
radial arteries in the endometrium are branches of?
arcuate arteries
radial arteries give rise to?
straight arteries-basal
spiral arteries-functional
terminal capillaries-functional
what marks the transition between the proliferative and secretory phase of the stratum functionale?
ovulation
what is the name of the irregular folds of the mucosa in the cervix?
plicae palmitae
the epithelium in the side in contact with the uterus in the cervix is?
mucos secreting tall columnar epithelial cells
simple cuboidal/simple columnar epithelium
the epithelium of the cervix that faces the side of the vagina is?
pluri stratified squamous
are glands more abundant in endo or ecto cervix?
endocervix
mucous secreting glands in the lamina propria
vagina, 3 layers
-epithelium
stratified squamous non keratinized
lamina propria made of dense connective tissue with elastic fibers and small veins
-smooth muscle layer with an inner circular and an outer longitudinal smooth muscle layer
-adventitia, connective tissue made of a lot of elastic fibers contributing to the distensibility of this organ
NB:parasympathetic ganglia innervates the erectile tissue in the lamina propria
the theca interna layer produces which types of hormones? and are converted in? by what?
androgens by theca interna cells
converted in estrogens
by granulosa cells
estrogens=fundamental to prepare the female reproductive tract to transport and welcome the embryo in case of fertilization
