lecture 37 Flashcards
name the layers of the uterine wall from outermost to innermost. which layer is shed during menstruation?
perimetrium
myometrium
endometrium (shed)
which artery associated with the female reproductive tract branches directly off the abdominal aorta? which ligament does it run through?
ovarian artery, runs through the suspensory ligament
name the fingerlike projections on the infundibulum. what is their purpose?
fimbriae help guide the oocyte to the opening of the uterine tube
ovary is the site of what?
oogenesis
what is the most common site of fertilisation in humans?
ampulla
what is oogenesis?
formation and development of the oocyte from oogonia
what does oogenesis require?
mitosis and meiosis
what is the cycle of ovulation?
1 ovulation every 28 days on average
where do oocytes develop?
ovarian follicles
when does oogenesis begin?
before birth, then it stops and begins again from puberty to menopause
when the Ovary is developed and released what collects it?
the fimbriae of the uterine tube for potential fertilisation
what is the corpus luteum?
a major endocrine organ
what does the corpus luteum produce during the ovarian cycle?
progesterone
what happens to the corpus luteum if it is not fertilised?
it breaks down and forms a corpus albicans which eventually degrades
during mitosis the oogonium (stem cell forms)?
another oogonium and a primary oocyte
what is the primary oocyte, diploid or haploid?
diploid, 2n
the primary oocyte goes under DNA replication and forms what during meiosis I?
secondary oocyte (haploid) and a polar body
what happens to the polar body that is produced during meiosis I?
may or may not complete meiosis II
when is the secondary oocyte released?
during ovulation and specifically metaphase of meiosis II
why is there a formation of a polar body and the secondary oocyte in meiosis I?
because there is unequal cell division and majority of the cytoplasm goes to the secondary oocyte
population of oogonia increase by?
mitosis
when does mitosis stop?
before birth
oogonia differentiate to form?
primary oocytes
where does meiosis halt? and where does it begin again?
primary oocytes start meiosis and halt at prophase I. It begins again at puberty
at puberty females have how many oocytes?
~300 000
what regulates number of follicles recruited each ovarian cycle?
GnRh
how many oocytes will complete development and ovulate?
only one
when does meiosis Ii resume?
sperm penetrates plasma membrane of the ovum at fertilisation
what happens if secondary oocyte isn’t fertilised?
will degenerate (atresia) and therefore never complete mitosis
where does oocyte development occur?
within the developing follicle
what are the cells of the follicles?
granulosa cells
theca cells
what do granulosa cells produce?
estradiol
during ovulation where are the oocyte and corona radiate released?
into the peritoneal cavity
what hormones do the hypothalamus produce?
GnRh
gonadotrophin releasing hormone
what hormones do the ant. pituitary produce?
FSH (follicle stimulating hormone)
LH (luteinizing hormone)
what hormones are produced in the ovarian follicles?
estradiol
inhibin
what hormones are produced in the corpus luteum?
inhibin
progesterone
functions of GnRH?
release of FHS and LH
Function of FSH?
stimulate growth of ovarian follicles
function of LH?
surge of LH involved in ovulation, formation of corpus luteum
function of estradiol?
assist follicle growth with FHS bone and muscle growth endometrial growth secondary sex characteristics feedback to ant. pituitary
function of inhibin?
negative feedback to anterior pituitary to suppress FSH
Function of progesterone?
negatively feeds back to suppress GnRh
endometrial maturation
maintains pregnant state
what is the ovarian cycle?
the regular cyclic changes in the ovary and uterus that prepare an oocyte for fertilisation and endometrium for embryo implantation
two main phases of the ovarian cycle?
follicular phase
luteal phase
what are the phases of the uterine cycle?
menstrual phase
proliferative phase
secretory phase
menstrual cycles occur between?
menarche and menopause
what is menarche?
first menstrual period and occurs at 12-13 years old
what orchestrates menarche?
increase in sex steroid production by the gonads
what is menopause?
cessation of menstruation
when does menopause typically occur?
in early 50s
describe menopause?
reduction of estradiol and progesterone due to absence of or lack of response by follicles. there is no longer anterior pituitary feedback
what hormones are high due to menopause?
FSH/LH due to no anterior pituitary feedback
why do FHS levels begin to decrease during follicular phase?
because growing follicles secrete estradiol which reduces FSH via negative feedback
dominant follicle secretes large amounts of what?
estradiol
high estradiol stimulates what?
a surge of LH (positive feedback)
what happens when the dominant follicle ruptures?
ovulation occurs and oocyte enters peritoneal space/ collected into uterine tube
ovulated follicle collapse and forms?
corpus luteum
what does the ovulated follicle and corpus luteum secrete? and what does this cause?
progesterone
estradiole
inhibin
this causes decrease in FHS, LH and GnRH
in which phase does the destruction of the endometrium take place?
menstrual phase
what stimulates endometrial growth from days 6-14?
estradiol
what does progesterone promote?
endometrial maturation
what happens during endometrial maturation?
glands become secretory
spiral arterioles grow and coil
what happens if fertilisation and implantation do not occur?
corpus luteum atrophies
progesterone levels fall
spiral arteries contract
menstrual phase begins again
