ANTEPARTUM #2 REPRODUCTION,CONCEPTION,FETAL GROWTH AND DEVELOPEMENT Flashcards
REPRODUCTIVE FUNCTIONING IS DEPENDENT UPON HORMONAL ACTION
- estrogens
- progesterone
- prostaglandins
- FSH and LH
- so what is the action of the hormones?
TWO PHASES OF THE OVULATION CYCLE
THE FILLICLE PHASE (DAYS 1-14)
-follicle matures and ovulation occurs
THE LUTEAL PHASE (DAY 15-28)the ovum leaves the follicle, and the corpus luteum develops from the ruptures follicle
-begins when
FOUR PHASES OF THE MENSTRUAL CYCLE
- menstrual
- poliferative
- secretory
- ischemic
MENSTRUAL PHASE
occurs during the menstrual phase with shedding of some, but not all endometrial cells
PROLIFERATIVE PHASE
the endometrial cells enlarge and become twisted under the influence of estrogen, and the endometrium thickens
SECRETORY PHASE
- progesterone causes marked swelling and the amount of tissue glycogen increases
- vascularity of the entire uterus increases greatly, providing a nourishing bed for implantation
- follows ovulation
ISCHEMIC PHASE
- begins if implantation doesn’t occur
- corpus luteum begins to degenerate
- estrogen and progesterone levels fall
- this phase is characterized by the escape of blood into the stromal cells of the uterus
MITOSIS
process of cellular division by which soma cells give birth to identical daughter cells
MEIOSIS
process of cellular division by which sex cells reproduce( known as gametogenesis)
OOGENESIS
- produces the female gamete (ovum)
- meiosis begins in oocytes before the female is born
- suspended until puberty, just before ovulation the first meiotic division occurs
- the second meiotic division is completed until immediately after fertilization
SPERMATOGENESIS
doesn’t begin to take place until puberty
TIMING FERTILIZATION
- ova fertile 12 -72 hrs after ovulation
- sperm survive 48-72hrs (highly fertile for 24 hrs)
- timeframe for the two to unite is limited
THE OVUM CANNOT MOVE ON ITS OWN
- high estrogen levels
- peristalsis to move the ovum
- thinning of the cervical mucus to facilitate sperm movement
- fertilization takes place in the ampulla
EACH EJACULATION CONTAINS 200 TO 500 MILLION SPERMATOZOA
- spermatozoa propel by movement of tails
- transit time from the cervix into the fallopian tube
5 min
2-7 hrs
FERTILIZATION
a chemical reaction takes place when the sperm penetrates the ovum so that only a single sperm enters
NUCLEI UNITE
- fertilization occurs
- chromosomes pair up
- diploid zygote results with 46 chromosomes
- females are XX
- males are XY
TWINS
FRATERNAL
- two ova and two sperm
- originate at conception
IDENTICAL
- single fertilized ovum
- originate at different stages
GESTATIONAL DATES(LMP) VS POST CONCEPTION DATES
-280 days or 10 lunar months or 40 weeks begins with first day of LMP
1st trimester- week 1-13
2nd trimester - week 14-26
3rd trimester- week 27 until term
-this is used in clinical
MULITIPLICATION
- cleavage series of rapid miotic divisions
- cells form a morula (solid ball)
- morula enters uterus and develops into a blastocyte with following components
fluid filled cavity
inner cluster of cells
~ developes into embryonic disk(embryo) and amnion (inner fetal membrane)
outer layer of cells called trophoblast
~developes into chorion(outer fetal membrane ) and fetal portion of placenta
IMPLANATATION
- 7-10 days after fertilization
- blastocyst burrows into endometrium
- endometrium now called decidua
- basilis (paortion of endometrium directly under embedded blastocyst) maternal side of placenta develops from basilis
PLACENTA
- metabolic and nutrient exchange membrane allows maternal and fetal blood to remain separate
- maternal portion (decidua)
- fetal portion -consist of he chorionic villi formed from the trophblast
- fetal surface covered by amnion
- by week 14 a discrete organ
PLACENTAL FUNCTIONS
- by way of metabolic and transfer activities the placenta functions include:
nutrition excretion fetal respiration production of fetal nutrients production of hormones
FETAL CIRCULATION
- O2 concentration higher in maternal blood so O2 diffuses across placenta membrane into fetal blood
- hemoblobin in fetal RBC has higher affinity (attraction for O2) when compared to adult
- highest oxygen concentration delivered to head, neck,brain and heart leading to cephalo-caudal developmental pattern
THREE STAGES OF HUMAN DEVELOPEMENT
PREEMBRYONIC
-fertilization thru day 14 includes implantation
EMBRYONIC
-day 15 thru end of week 8
FETAL
-end of week 8 until birth
FETAL DEVELOPMENT WEEK 4
- primitive tubular heart begins to beat by 28 days
- placenta functions but with minimal metabolic exchange
FETAL DEVELOPMENT WEEK 8
- at 8 weeks embryo slightly more than one inch long
- by end of 8th week all body systems have been laid down (organogenesis complete) now called fetus
FETAL DEVELOPMENT WEEK 9-12
- spontaneous movement occurs
- fetal heart tones can be heard with Doppler between 8-12 weeks
- urine is produced
- genitals are well differentiated by end of week 12
FETAL DVELOPMENT WEK 13-16
- fetus makes sucking motions
- swallows amniotic fluid
- produces meconium
- by week 16 lanugo begins to develop
FETAL DEVELOPMENT WEEK 20
- fetal movement (quickening ) felt by mom
- lanugo covers entire body
- vernix coseosa appears
- brown fat deposits begin
- fetus weighs a little less than 1lb and measures about 8 inches in length
FETAL DEVELOPMENT WEEK 24
- vernix caseosa covers skin
- alveoli in lungs begin to form
- fetal respiratory movements begin, there is no gas exchange across aveoli
- surfactant production begins
- both grasp and startle reflexes present
- fingerprints and footprints present
FETAL DEVELOPMENT WEEK 28
- brain developing rapidly
- nervous system begins to regulate
- eyelids open and close
- lungs immature but developed enough to provide gas exchange if delivered
- fetus 2/3 final length
- weight a little less than 3lbs
FETAL DEVELOPMENT WEEK 32
- subcutaneous (white) fat deposited
- at 32 weeks weighs a little less than 4lbs
FETAL DEVELOPMENT WEEK 35-36
- increase in subcutaneous white fat
- lanugo begins to disappear
- surfactant production adequate
- weighs 5-6lbs
- good chance for survival but may require special care
FETAL DEVELOPMENT WEEK 38
- full term
- skin smooth and polished
- vernix caseosa in creases and folds
- head bigger than chest
- last few weeks gets IgG antibodies from mom
FACTORS INFLUENCING DEVELOPMENT
- quality of sperm or ovum
- genetic code
- adequacy of intrauterine environment
- teratogens
TERATOGENS
- viral infections can cross placental membranes and infect fetus
- TORCH infections
- rubella first trimester, congenital heart disease, mental retardation, cataracts
- prescription drugs
-Illicit drug use marijuana cocaine opiates methamphetamine
