A + P Reproductive System II Flashcards
female reproductive cycle
- two cycles
- other components that affect the reproductive cycle
ovarian cycle uterine cycle other -hormonal changes that regulate them -cyclical changes in the breasts and the cervix
ovarian cycle
- what is it
- phases
a series of events associated with the maturation and release of an ovum phases -follicular phase -ovulation -luteal phase
follicular phase
-days
period of follicular growth in the ovary
most variable in length, from 10-14 days
ovulation
-days
once the follicle has ripened, the ovary releases the ovum
occurs approximately on day 14
luteal phase
-days
days 15-28
luteal phase
-if fertilization and implantation do not occur
corpus luteum degenerates
decreased secretion of progesterone and estrogens
-causes shedding of the stratum functionalis
-initiates another uterine and ovarian cycle
luteal phase
-if fertilization and implantation do occur
will occur within 24 hours after ovulation
corpus luteum is maintained until the placents takes over its hormone-producing function
during this time th ecorpus luteum secretes estrogens and progesterone to support pregnancy and breast development for lactation
this interrupts the menstrual cycle and prevents the loss of the stratum functionalis
once the placenta begins its secretion, the corpus luteum will degenerate
uterine (menstrual) cycle
involves changes in the endometrium to prepare for the reception of a fertilized ovum
highly variable duration from 20-45 days (28 is average)
uterine cycle phases
menses (menstruation)
proliferative phase
secretory phase
menses
- days
- 1st day
- stratum functionalis
- secondary follicles
first 3-7 days of the cycle
1st day of menstruation or blooding considered 1st day of the cycle
during this phase, the stratum functionalis is shed, which discharges blood tissue fluid, mucus, and epithelial cells
small secondary follicles in each ovary begin to develop from primary follicles
proliferative phase
- days
- endometrium
lasts from days 6-13 in a 28-day cycle
endometrium adds a new layer of cells (stratum basalis) in anticipation of implantation of a fertilized ovum
secretory phase
- days
- after ovulation
- if no pregnancy
usually on day 14 in a 28-day cycle
after ovulation, hormones from the corpus luteum convert the stratum basalis into a secretory structure and the stratum functionalis is formed
if no pregnancy occurs during this phase, the stratum functionalis is prepared to be released again during menses
when does hormonal regulation of the female reproductive cycle begin
onset of puberty
hormones involved in the female reproductive cycle
GnRH Follicle-stimulating hormone (FSH) leutenizing hormone (LH) estrogens progesterone relaxin inhibin
GnRH
- from
- controls
- stimulates
from the hypothalamus
controls ovarian and uterine cycles
stimulates the relase of FSH and LH by the anterior pituitary gland
follicle-stimulating hormone
-stimulates
stimulates
- secretion of estrogens by the ovaries
- initial development of ovarian follicles
- full development of at least one follicle each month to produce a mature ovum
leutenizing hormone
-stimulates
stimulates
- further development of ovarian follicles
- ovulation
- secretion of estrogen and progesterone by the ovaries
estrogens
- how many
- functions
at least 6 different estrogens have been isolated from the plasma of human females
functions
-development and maintenance of female reproductive structures, menstruation, secondary sex characteristics
-regulation of fluid and electrolyte balance
-stimulation of protein synthesis
progesterone
- works with
- function
works with estrogens to prepare the endometrium for implantation and the mammary glands for milk synthesis
relaxin
- when is it produced
- function
- during pregnancy
produced monthly to relax the uterus by inhibiting contractions
-makes it easier for a fertilized ovum to implant in the uterus
during pregnancy, relaxin relaxes the pubic symphysis and helps dilate the uterine cervix to facilitate delivery
inhibin
- function
- might be important for
inhibits secretion of FSH and GnRH and, to a lesser extent, LH
might be important in decreasing secretion of FSH and LH toward the end of the uterine cycle
what is pregnancy
sequence of events that normally includes fertilization, implantation, embryonic growth, and fetal growth, that ends with birth about 28 weeks later
fertilization
- how
- where does it occur
- within what time after ovulation
- spermatazoa
- when a sperm enters the ovum
the genetic material from a haploid sperm cell and a haploid ovum merge into a single diploid nucleus
normally occurs 1/3 of the way down the uterine tube, usually within 12-24 hours after ovulation
spermatazoa swims up the uterus and into the uterine tube by the whiplike movements of their tails and muscular contractions of the uterus
once a sperm enters the ovum, the male and female pronuclei fuse to form the fertilized ovum or zygote
identical (monozygotic) twins
- derived from
- contain
derived from a single fertilized ovum that splits at an early stage in development
contain exactly the same genetic material and are always the same sex
fraternal (dizygotic) twins
- produced from
- they are
- consequently
produced from the independent release of two ova and the subsequent fertilization of each by different spermatazoa
they are the same age and are in the uterus at the same time, but are as genetically dissimilar as other siblings
consequently, fraternal twins can be different sexes
hatching
- what happens
- zygote becomes knows as
- -around what time
- embryoblast and trophoblast turn into
zygote continues to divide, creating an inner group of cells (embryoblast) with an outer shell (trophoblast)
at this stage the zygote becomes known as a blastocyst (around day 5)
embryoblast cells will become the embryo
trophoblast cells will become the placents that nourishes and protects the embryo
implantation
- attachment of
- -when does it occur
attachment of a blastocyst to the endometrium occurs 7-8 days after fertilization
called implantation
embryonic and fetal development
-divisions
first trimester
second trimester
third trimester
first trimester
- when
- first two months
0-3 months
first two months is the embryonic period
embryonic period
- what happens
- by the end
time during which the embryo is developed
by the end of this time, the rudiments of the principal organs are formed, and the placenta is functioning
parts of the embryo
amnion
placenta
umbilical cord
amnion
- visual
- forms by
- as the embryo grows
- usually ruptures when
thin, protective membrane
forms by day 8 of fertilization
as the embryo grows, the amnion entirely surrounds the embryo, creating a cavity that becomes filled with amniotic fluid
amnion usually ruptures during labor and expels fluid
placenta
- formed by
- happens by
- functions
formed by the chorion of the embryo and a portion of the endometrium of the mother by the end of the embryonic period
functions
-allows O2 and nutrients to diffuse into fetal blood from maternal blood and CO2 and wastes to diffuse from fetal blood into maternal blood
-provides protection, since most microorganisms cannot cross it
-stores nutrients such as carbohydrates, proteins, Ca2+, and Fe, which are released into fetal circulation as required
produces several hormones that are necessary during pregnancy
umbilical cord
- what is it
- consists of
vascular connection between the placenta and fetus
consists of
-two umbilical arteries carrying deoxygenated fetal blood to the placents
-one umbilical vein carrying oxygenated blood from the placenta to the fetus
when does the embryo name change
what does it change to
from the start of the third month until birth, the embryo is referred to as a fetus
remainder of pregnancy is knows as the fetal period
second trimester
- time
- what happens
- by 6th month
4-6 months
continued development of organs and organ systems
by 6th month, fetus begins to look like a small human
third trimester
- time
- what happens
- by early 7th month
7-9 months
rapid fetal growth and deposition of adipose tissue
most major organs functionby by early 7th month
labor
-what is it
process by which the fetus is expelled from the uterus through the vagins
what primarily controls the onset of labor
hormone oxytocin
stages of labor
dilation stage
expulsion stage
placental stage
dilation stage
- what is it
- lasts
- characteristics of uterine contractions
- rupture of amniotic sac
onset of contractions to complete dilation of cervix (10 cm)
typically lasts from 6-12 hours
regular contraction of the uterus
-early on they may be 10-30 minutes apart lasting 20-30 seconds
-progress to under 2-3 minutes lasting 60 seconds
rupture of amniotic sac may happen naturally or could be done manually, which may speed up labor
expulsion stage
- when does it occur?
- length
- what will decrease the time?
from complete cervical dilation to delivery
may last from a few minutes to several hours
time in this last stage may be decreased with additional deliveries
placental stage
- when
- what facilitates delivery of the placenta
from delivery of baby to delivery of placenta (afterbirth)
powerful uterine contractions facilitate delivery of placenta
Cesarean section (c-section)
- involves
- when are they necessary
involves making an abdominal incision into the uterine through which the baby can be removed
often necessary
-if baby is to big
-baby is aligned incorrectly for vaginal delivery
-to prevent possible complications during labor
maternal changes during pregnancy
corpus luteum placenta uterine enlargement skin miscellaneous changes cardiovascular modifications pulmonary modifications
corpus luteum
- when
- what happens
during the first 3-4 months of pregnancy, the corpus luteum continues to secrete progesterone and estrogens to maintain the uterine lining and prepare the mammary glands to secrete milk
placenta
-function
once formed, the placenta takes over the corpus luteum’s role and provides high levels of progesterone and estrogens for the remainder of the pregnancy
uterine enlargement
-what happens
uterus continuously enlarges, filling first the pelvic and then the abdominal cavity, displacing and compressing a number of structures
pressure on the bladder increases frequency and urgency of urination
skin
-what happens
increased pigmentation, and striae (stretch marks) develop over the abdomen as the uterus enlarges
miscellaneous changes
weight gain increased appetite increased protein, fat, and mineral storage breast enlargement lower back pain possible nausea, vomiting, and heartburn
cardiovascular modifications
increased BV, SV, HR, and Q
pulmonary modifications
increased VT and VE, and bronchodilation
