Embryonic development, birth,etc Flashcards
3 embryonic tissue layers form. Most organ systems form and limb bubs with tiny toes and fingers are visible. by 9th week- referred to as a fetus
First trimester
All organs formed but not fully developed. Development continues and fetus size increases. Bony parts of skeleton begin to form
Second trimester
Rapid growth-organs enlarge and finish development. Organ systems(circulatory & respiratory) mature in preparation for breathing
Third trimester
Involves a number of hormonal and physical changes in mother’s body. triggered by falling progesterone and estrogen levels-aging placenta not producing as many hormones
Child birth
Baby’s head shifts downwards and contacts cervix. Placenta secretes _ - helps dilation of cervix and causes ligaments within pelvis to loosen
relaxin
Dilation of cervix stimulates the hypothalamus to secrete _. __ stimulates the uterus to contract.
Oxytocin
Strong rhythmic contractions of uterus= __. The contractions move from upper part of uterus and sweep downwards.
Labor
The more cervix dilates= more =__ released = more dilation(positive feedback loop)
oxytocin
__ from glands in uterine wall appear in mother’s blood prior to labour-these trigger strong uterine contractions
Prostaglandins
strong and frequent contractions propel fetus down birth canal and out the vagina
delivery
After delivery, the __ is clipped and cut
umbilical cord
Uterus continues to contract to dislodge 1.__ from uterine wall which is expelled as “2.__”
- placenta
- Afterbirth
during pregnancy estrogen and progesterone prepare breasts for __
milk production
there are about 20 lobes of __ tissue per breast- each lobe has a small duct that carries fluid towards the nipple
glandular
__ stimulates the breast to produce fluid.
Prolactin
Is inhibited before child birth as high levels of progesterone inhibit action of prolactin
Milk production
At birth estrogen and progesterone levels drop rapidly increasing __ activity. __ ,at first, stimulates production of colostrum.
prolactin
a fluid like breast milk but lacking in fat
colostrum
does not flow readily but has to be pushed into ducts leading to nipple.
Breast milk
a series of events that start with feeding action of a baby
Milk release
Stimulation of 1.__ in nipple and 2.__. Nerve impulse to hypothalamus, release of oxytocin which cause contractions of 3.__ focing milk out
- sensory neurons
- Areola
- smooth muscle
a small sample of tissue is removed from chorionic villi in the early stages of pregnancy to check for presence of genetic defects in fetus(karyotype)
Chorionic villi sampling
insert a hollow needle through abdominal wall into uterus. Small amounts of amniotic fluid and live fetal cells are withdrawn. Chromosomal analysis (karyotype) can determine if baby has defects such as down syndrome, cystic fibrosis & hemophilia. Offered between 15 & 18 weeks of pregna. to woman who has increased risk of having baby with genetic abnormalities
Amniocentesis
sound waves used to determine baby’s position and size
ultrasound
IVF
In vitro fetilization
IVF example: adminster purified forms of fsh
ovarian stimulation
IVF example: (two methods) 1. laparoscopy
2. ultrasound allows physician to guide a needle into each follicle to withdraw eggs
egg retrieval
insert a laparoscope into ovaries and use light suction to retrieve egg from follicle.
Laparoscopy
IVF example: Mix semen with eggs and incubate at a temperature identical to a woman’s body
Fertilization
IVF example: embryos are placed in a catheter (a tubular instrument) which is inserted into the vagina and cervix to transfer the embryos to the uterus.
Embryo transfer
Ovarian stimulation, egg retrieval, fertilization in lab followed by transfer of zygotes into female Fallopian tubes
Gamete intrafallopian transfer (GIFT)
Insertion of a single sperm directly into cytoplasm of mature egg using microinjection pipette (thin glass needle). Helps overcome infertility problems cause by sperm that are unable to penetrate egg. Zygote is then inserted into uterus or Fallopian tube.
Intracytoplasmic sperm injection (ICSI)
patients are given ovulation stimulation medications and monitored to see when the egg are mature. 24-36 hours after LH spike, a sample of semen is washed by lab to separate semen from seminal fluid. A catheter is used to insert sperm directly into uterus . Maximises the number of sperm in uterus.
intrauterine insemination
used by individuals with infertility issues to sperm disorders. Sperm injection into female repro. tract through catheter-could be cervix, uterus or fallopian tubes
Artificial insemination
donor eggs can be used for in vitro fertilization when female has a genetic disorder, reproduction abnormalities, received radiation or chemotherapy,had failure IVF attempts or recurrent miscarriages. Donor sperm can be used when infertility problems arise.
Donor eggs and Donor sperm
2 eggs, 2 sperm, differnt placentas, have different DNA
fraternal twins
1 egg-splits- can share the same placenta, same DNA
Identical twins
choose embryo-eye color,athletic ability,height,etc. sperm for sale
Controversy
abnormalities corrected in uterus
Prenatal surgery
