reproduction 2 Flashcards
the uterine ( ____ ) tubes ( ____ ) are not directly attached to the ovaries, but open into the ____ cavity near the ovaries with the opening surrounded by projections called ____ ; their other ends are attached to the uterus and empty into its cavity
fallopian
oviducts
abdominopelvic
fimbriae
cervix
inferior part of the uterus and opens into the vagina
functions of the ovaries
ooogenesis (during the fetal period)
maturation of the oocyte
expulsion of the mature oocyte (ovulation)
secretion of estrogen, progesterone, and inhibin
oogenesis
the division of stem cell oogonia (primitive germ cells) by numerous rounds of mitosis to produce a clone of oogonia
occurs during early fetal development
at birth, the ovaries contain ____ “eggs” and no new ones appear after birth
roughly 400 of these will be ____ during the female’s lifetime
the others ____ at some point in their development so that few if any remain by the time she reaches the age of about ____
2-4 million
ovulated
degenerate, 50
during fetal life, all the oogonia eventually develop into:
these cells then begin meiosis ____ (by replicating their DNA), but do not complete the ____
primary oocytes
I , division
at birth, all the eggs present are ____ oocytes containing ____ chromsomes, each with ____ sister chromatids, in a state of meiotic arrest
this continues until ____ and the beginning of renewed activity in the ovaries
primary, 46, 2
puberty
completion of meiosis I occurs just before the egg is ____ in a give reproductive cyle (thus, only those eggs destined for ovulation ever complete meiosis ____ )
ovulated
I
at the completion of meiosis I, each daughter cell contains ____ chromsomes (each with ____ chromatids), but one daughter cell - the ____ oocyte - receive nearly all of the cytoplasm
the other daughter cell called a ____ ____ , is small and nonfunctional
23, 2, secondary
polar body
meiosis II occurs in a ____ ____ after ____, but only if the secondary ooxyte has been ____
uterine tube, ovulation, fertilized
in meiosis II, one daughter cell, now called an ____ , recieves nearly all the cytoplasm, and the other cell, again called a ____ ____ is small and nonfunctional
as a result of meiosis II, the daughter cells each have ____ chromosomes, each with ____ chromatid
ovum, polar body
23, 1
a newly fertilized egg is called a
zygote
follicle growth:
- eggs in the ovaries exist in structures known as ____
- follicles begin as ____ follicles, each of which consists of one primordial ____ (about to become a primary oocyte) surrounded by a single layer of ____ cells
- before but mostly after birth, the primordial follicles develop
- the ____ gets larger, the ____ cells proliferate by mitosis into multiple cell layers, and the oocyte becomes separated from the inner granulosa layer by a layer of glycoprotein material called the ____ ____
- follicles
- primordial, ovum, granulosa
- oocyte, granulosa, zona pellucida
the glycoproteins (that make up the zona pellucida) play a role in binding
the sperm to the surface of the egg
granulosa cells secrete ____ and ____ and, just before ovulation, small amounts of ____
estrogen
inhibin
progesterone
small cytoplasmic processes connect the inner granulosa cells with
the oocyte and allow nutrients and chemical messengers to reach the oocyte
as the follicle continues to grow after birth, ____ cells form outside of the granulosa cells, the primary oocyte reaches full size, and the ____ , a fluid-filled space, forms in the midst of the granulosa cells as a result of the fluid they secrete
theca
antrum
some primordial follicles progress to the early antral stages during infancy and childhood; for others, this occurs during the post-pubertal female’s reproductive cycles:
at the begining of each reproductive (menstrual) cycle, ____ preantral/early antral follicles begin to develop further
10-25
although most follicles in the ovaries remain primordial, a nearly constant number of preantral and early antral follicles are also present
at all times
on about day ____ of the cycle, one follicle is “selected” as the ____ follicle, and only it continues to develop
7
dominant
____ also occurs between birth and puberty so that only 300,000 follicles remain when active reproductive life begins
99.99% of the ovarian follicles present at birth will undergo atresia rather than producing an egg that is ____
atresia
ovulated
as the antrum of the dominant follicle continues to enlarge, the ____ cell layers surrounding the egg form a mound, the ____ ____ , that projects into the antrum
granulosa
cumulus oophorous
as ovulation approaches, the ____ oocyte emerges from meiotic arrest and completes ____ ____ to become a ____ oocyte
the cumulus separates from other cells so that it and the oocyte float free in the ____ fluid
primary
meiosis I
secondary
antral
a mature follicle, also called a ____ follicle, becomes so large that it balloons out on the ____ surface
Graafian
ovary’s
ovulation:
on about day 14, the thin walls of the ____ and ____ rupture at the site where they are joined due to ____ digestion
the secondary oocyte (along with the adhering zona pellucida and cumulus) is carried by the ____ fluid out of the ovary and onto the ovarian surface
follicle and ovary
enzymatic
antral
a cell that is ovulated is a
secondary oocyte
formation of the corpus luteum:
- the remnant of the follicle collapses after ovulation and changes rapidly, partly due to enlargement of the granulosa cells, resulting in formation of a gland-like ovarian structure, the ____ ____
- the corpus luteum secretes ____ , ____ , and ____ , and in the absence of fertilization, reaches maximum development in about 10 days
- after that, it rapidly; degenerates by apoptosis, and its degeneration leads to ____ and the start of a new cycle
- if fertilization occurs, it grows and persists until near the end of ____ , and has an important function in pregnancy
- corpus luteum
- estrogen, progesterone, and inhibin
- menstruation
- pregnancy
follicular phase:
luteal phase:
mature follicle and secondary oocyte develop
beginning after ovulation and lasting until the death of the corpus luteum
sites of hormones production:
- estrogen is synthesized/released into the blood during the follicular phase mainly by ____ cells, and during the luteal phase by the ____ ____
- progesterone is synthesized/released into the blood in very small amounts during the follicular phase (just before ovulation) by ____ and ____ cells, and during the luteal phase in large amounts by the ____ ____
- inhibin is secreted by:
- granulosa , corpus luteum
- granulosa and theca, corpus luteum
- both granulosa cells and by the corpus luteum
control of ovarian function:
GnRH is released by the ____ in pulses (as in males), but (unlike in males), the pulse frequency and amplitude changes greatly over the course of the menstrual cycle
the responsiveness of the anterior pituitary to ____ and of the ovaries to ____ and ____ also change over the course of each cycle
hypothalamus
GnRH
LH and FSH
control of ovarian function:
- ____ increases in the early follicular phase and then steadily decreases through the rest of the cycle except for a small ____ peak
- ____ is constant for most of the follicular phase but shows a large midcyle increase that peaks about 18 hours before ____ ; it slowly declines during the luteal phase
- ____ is farily low and constant during the first week but increases rapidly during the second week as the dominant follicle grows and secretes more of it. it starts declining shortly before the LH surge and then undergoes a second increase that peaks on about day 21 due to secretion by the corpus luteum. it rapidly decreses during the last days of the cycle
- small amounts of ____ are released during the follicular phase. soon aftter ovulation, very large amounts are released by the corpus luteum and from this point its pattern is similar to that of estrogen
- the pattern for ____ is similiar to estrogen
- FSH, midcycle
- LH, ovulation
- estrogen
- progesterone
- inhibin
control of ovarian function - early and middle follicular phases:
- follicle development beyond the early antral stage requires ____ (prior to puberty, FSH is too low to do this)
- the FSH increase that starts on about day 26-27 is due to the removal of negative feedback due to increased ____ , ____ , and ____ levels
- the resulting FSH stimulates a group of preantral and early antral follicles to ____
- FSH acts on ____ cells, stimulating them to multiply and produce ____ (by converting angdrogen into estrogen) ; it also stimulates antrum enlargement
- some of the estrogen produced diffuses into the blood and maintains a relativley ____ plasma concentration
- the estrogen also functions as a paracrine or autocrine messenger within the follicle wehre (along with FSH and other molecules) it stimulates ____ cell proliferation, leading to more estrogen
- FSH
- estrogen, progesterone, and inhibin
- enlarge/develop
- granulosa, estrogen
- constant
- granulosa
- granuosa cells cannot produce estrogen without its precursor ( ____ ) , thus…
- ____ acts on ____ cells, stimulating them to proliferate and to synthesize androgens
- the androgens diffuse into nearby ____ cells and are converted within the granulosa cells into estrogen by ____
- androgen
- LH, theca
- granulosa, aromatase
estrogen secretion in the follicular phase requires the interplay of both types of follicle cells ( ____ and ____ ) and both types of pituitary gonadotropins ( ____ and ____ )
granulosa and theca cells
FSH and LH
comparing male and female reproduction:
- granulosa cells are similiar to ____ cells because they
- control the environment in which ____ cells develop and mature and
- are stimulated by both ____ and the major gonadal sex steroid (____ )
- theca cells are simliar to ____ cells because they
- produce mainly ____ and
- are stimulated to do so by ____
- sertoli
- germ
- FSH, testerone
- leydig
- androgens
- LH
by about day 7, one follicle has become ____ ; the other developing follicles degenerate, probably because ____ has fallen to the point where there is noth enough of it to prevent ____
dominant
FSH
atresia
why does the dominant follicle survive?
estrogen (which is slowly rising) causes its granulosa cells to form increasing numbers of FSH receptors, causing positive feedback as the granulosa cells are even more sensitive to FSH
the dominant follicle begins secreting enough ____ that its plasma level begins increasing
____ begins to fall because low-to-moderate levels of estrogen exert negative feedback on the pituitary’s secretion of gonadotropins
estrogen probably also exerts negative feedback at this time on the hypothalamus to decrease ____ secretion; thus the plasma level of ____ (and to a lesser extent, LH) falls as estrogen rises on about days 6-11
estrogen
FSH
GnRH, FSH
hormonal feedback day 9:
at this time, the granulosa cells secrete ____ , which (as in males) appears to have a greater effect of decreasing ____ secretion than LH secretion
inhibin
FSH
control of ovarian function - LH surge and ovulation:
- the inhibitor effect of estrogen on ____ and ____ secretion occurs when plasma estrogen is low-to-moderate, on about days 6-11
- rising plasma levels of estrogen for 1-2 days (around day 12) act on the anterior pituitary to ____ the sensitivity of the LH-secreting cells to GnRH
- there may be positive feedback also on the ____ when estrogen levels are high, increasing GnRH secretion
- FSH and LH
- enhance
- hypothalamus
- the positive feedback provided by the rapidly rising estrogen leads to the LH surge on day ____ ; the LH surge is the primary event that induces ____ ; this includes LH’s actions on granulosa cells that cause…
- them to release messengers that act on the primary oocyte so that it completes ____ ____ and undergoes other changes to prepare it for ____
- them to start releasing small amounts of ____ and to decrease their release of ____
- them to produce enzymes that break down the follicular-ovarian membranes, which ____ , allowing the oocyte to be carried out on to the ovarian surface
- 14, ovulation
- meiosis I, implantation
- progesterone, estrogen
- rupture
control of ovarian function - the luteal phase:
- the LH surge has the additional function of stimulating the remaining granulosa cells of the ruptured follicle to become transformed into the ____ ____ , which starts releasing large amounts of ____ and ____ , as well as some inhibin
- a low but adequate ____ concentration maintains the function of the corpus luteum for (assuming the egg is not fertilized) about 2 weeks
- corpus luteum, estrogen and progesterone
- LH
control of ovarian function - the luteal phase:
- in the presence of ____ , the high concentration of ____ causes a decrease in the pituitary’s LH and FSH secretion; this effect probably occrs by progesterone (and estrogen) exerting negative feedback on the hypothalamus to inhibit GnRH release
- the high progesterone level also prevents any ____ surges during the first half of the luteal phase despite the high ____ level as this time
- the plasma level of inhibin increases during the mid-luteal phase, and exerts ____ feedback to aid in suppresing FSH secretion
- the inhibitory effects of progesterone and inhibin keep plasma ___ and ____ levels very low during the luteal phase
- however the corpus luteum has a finite life in the absence of an increase in ____ and ____ secretion, and it degenerates within about 14 days
- estrogen, progesterone
- LH, estrogen
- negative
- LH and FSH
- LH and FSH
when the corpus luteum loses its yellowish appearance and secretory abilitiy (on about day ____ ), it is called the ____ ____ ; during the next few weeks, the corpus albicans is replaced by connective tissue and over moinths it is absorbed
26
corpus albicans
the corpus luteum degeneration causes a decrease in ____ and ____
____ , ____ , and ____ secretion increase as a result of being freed from the inhibiting effects of high levels of estrogen and progesterone
the reproductive cycle then begins anew
estrogen and progesterone
LH, FSH, and GnRH
uterine changes and control of uterine function:
- menstrual flow begins on day 1 and typically lasts ____ days ; this time is the ____ phase of the uterine cycle
- during this time, the ____ (uterine epithelail lining) degenerates and is lost from the body
- after cessation of menstrual flow, the endometrium regenerates and thickens during the ____ phase, under the influcence of ____ ; this phase is roughly between days 4 or 5 and 14
- from ovuluation until the start of the next period of menstural flow is the ____ phase of the uterine cycle
- during this phase, the ____ , under the influence of ____ and ____ , begins to secrete glycogen, glycoproteins, and mucopolysaccharides
- 3-5 days, menstrual
- endometrium
- proliferative, estrogen
- secretory
- endometrium, estrogen and progeterone
the uterine changes over 28 days are due to changes in estrogen and progesterone levels:
- during the proliferative phase, increasing plasma ____ stimulates growth of the endometrium and the underlying uterine smooth muscle tissue called ____
- estrogen also induces the synthesis during the ____ phase of receptors for ____ in the endometrial cells
- during the secretory phase, ____ acts on these receptors to convert the ____ to an actively secreting tissue so that the uterus will be suitable for implantation and nourishmen of an embryo
- the endometrial glands become coiled and filled with ____
- blood vessels becomes more ____
- ____ accumulate in the glands and connective tissue
- estrogen, myometrium
- proliferative, progesterone
- progesterone, endometrium
- glycogen
- numerous
- enzymes
the uterine changes over 28 days are due to changes in estrogen and progesterone levels:
- progesterone inhibits ____ contractions, partly by opposing the stimulatory actions of ____ and of locally produced ____. a non-contracting uterus is maintained by ____ throughout pregnancy and is essential to allow implantation and to prevent premature delivery
- under the influence of only ____ (days 5-14), the mucus secreted by the cervix is ____ and ____ , especially at the time of ovulation, which allows sperm to move easily through the mucus on their way to the uterus and uterine tubes
- ____ , in large amounts only after ovluation, causes the mucus to become ____ and ____ , and to become a sort of “plug” that prevents bacteria from entering the uterus from the vagin
- myometrial, estrogens, prostaglandins, progesterone
- estrogen, abundant and watery
- progesterone, thick and sticky
the uterine changes over 28 days are due to changes in estrogen and progesterone levels:
- the decrease in ____ and ____ when the corpus luteum dengerates deprives the thickened endometrium of its hormonal support and casues menstruation
- uterine blood vessels ____ , depriving the endometrial cells of ____ and ____
- uterine ____ muscle begins to undergo rhythmic ____
- both the contractions and the vasoconstriction are mediated by ____ produced by the endometrium in respone to the decrease in estrogen and progesterone levels
- (prostablandins also affect smooth muscle elsewehre in the body)
- after the initial period of vasoconstriction, the endometrial arterioles ____ , resulting in hemorrhage through the weakened capillary walls
- menstrual flow consist of blood mixed with ____ debris
- estrogen and progesterone
- constrict, oxygen and nutrients
- smooth, contractions
- prostaglandins
- dilate
- endometrial
other effects of estrogen:
- increases ____ and ____ activity of uterine tubes
- increases uterine responsiveness to ____
- increases thickness of ____ in ____
- stimulates growth of external ____ and ____ , especially during puberty
- is responsible for development of female body ____ during puberty
- stimulates bone growth and ultimate ____ thereof by closing epiphyseal plates
- stimulates ____ secretion but inhibits prolactin’s milk-inducing action on the breasts
- contractions and ciliary
- oxytocin
- epithelium in vagina
- genitalia and breasts
- configuration
- cessations
- prolactin
other effects of progesterone:
- inhibits ____ of cells lining the vagina
- decreases contractions of ____ ____ and ____
- stimulates ____ growth, espeically ____ tissue
- inhibits milk-inducing effects of ____
- increases body ____
- some of progesterone’s actions, especially on the ____ and ____ are antiestrogen
- in contrasts, in many tissues estrogen stimulates the synthesis of progesterone receptors; thus responsiveness to progesterone often often requires the presence of estrogen, a phenomenon called ____ priming
- proliferation
- uterine tubes and meymetrium
- breast, glandular
- prolactin
- temperature
- vagina and myometrium
- estrogen
androgen in females:
- produced by:
- stimulate:
- maintain:
- possibly stimulate:
- adrenal cortices and ovaries
- growth of pubic and axillary hair
- the sex drive
- growth of skeletal muscle
puberty:
- during childhood, ____ , ____ , ____ , and ____ are all secreted at very low levels; thus there is no follicle maturation beyond the early antral stage and reproductive dycles do not occur
- puberty begins, largely, because brain function changes in an as-yet-unknown way that increases the secretion of ____
- GnRH in turn stimulates the secretion of ____ and ____ , which stimulate follicle development and estrogen secretion
- estrogen induces the changes in the:
- ____ , the first menstruation, is a late event of puberty
- GnRH, LH, FSH, and estrogen
- GnRH
- FSH and LH
- accessory sex organs and secondary sexual characteristics associatetd with puberty
- menarche
menopause:
- peroid during which:
- occurs when:
- the cycle becomes irregular and ovulation often fails to occur, and then cycles cease completely; average age is 51.4 years
- the number of ovarian primordial follicles that remain to be stimulated by FSH and LH becomes very low to none; the production of estrogen decreases dramatically as the number of follicles approaches zero
female sexual response:
- is characterized by increases in:
- during intercourse, blood flow to vagina:
- blood flow and muscle contraction in several body areas, including breasts and clitoris
- increases and its epithelium becomes lubricated by mucus
