LAST ONE Flashcards
What aids sperm in reaching the egg
sperm must move upward through uterus by lashing its tail and is aided by muscular contractions within walls of uterus. high concentration of estrogens during first part of a watery fluid that promotes sperm transport
what helps sperm penetrate egg
enzymes are released from sperm cells
what keeps the rest of the sperm from entering
after fertilization, enzyme change the membrane of egg to prevent entry of additional sperm
what completes fertilization
fusion of the nuclei of sperm and egg
fertilized egg cell with 46 chromosomes
zygote
cells undergo mitosis giving rise to smaller cells
cleavage
the ball of cells moves down uterine tube where it implants in the _____ as a blastocyst
endometrium
formed from embryonic and maternal cells that attaches embryo to uterine wall
placenta
what is the purpose of human chorionic gonadotropin
hormone produced by embryonic cells that prevents miscarriage
stimulate breast development and prepares mammary glands for milk secretion
placental lactogen
secretion promotes retention of sodium and body fluid
aldosterone
helps maintain a high concentration of maternal blood calcium
parathyroid hormone
what is the time period considered an embryo
from beginning of 2nd week - 8th week of development
2 week old embryo with 3 primary germ layers
gastrula
membrane that forms outermost covering around embryo and helps form placenta
chorion
projections that extend from chorion and help attach embryo to uterine wall
chorionic villi
separates embryonic blood within capillaries of villi from maternal blood
placental membrane
membrane that encircles embryo and contains amniotic fluid
amnion
structure that connects embryo to placenta
umbilical cord
membrane that attaches to underside of embryo and forms blood cells in early development
yolk sac
tube extending from yolk sac and gives rise to umbilical cord blood vessels
allantois
what is the time period considered a fetus
begins at 9th week and lasts until birth
how is oxygen concentration different and why
fetal blood carries a greater concentration of oxygen than maternal blood; more hemoglobin
blood enters fetus through umbilical vein and partially bypasses liver through the __
ductus venosus
bypass route around lungs
blood enters right atrium and partially bypasses lungs and through foramen ovale. blood in pulmonary trunk partially bypasses lungs through the ductus arteriosus
opening in artial septum
foramen ovale
vessel that bypasses blood into pulmonary trunk
ductus arteriosus
4 factors that promote birth
progesterone decreases which stimulates release prostaglandin that promotes uterine contraction.
cervix begins to thin and open.
stretching of uterine and vaginal tissue.
pituitary gland releases hormone oxytocin which stimulates uterine contraction.
following birth, placenta separates from uterine wall and is expelled
afterbirth
why is milk not secreted til birth
placental lactogen blocks milk production
watery fluid, rich in protein secreted by mammary glands and contains antibodies from mother’s immune system
colostrum
what causes milk to be secreted by nipple ejection
mechanical stimulation of nipple causes milk to be ejected
name 4 things newborns must do
must begin to breathe, obtain and digest nutrients, excrete waste, and regulate body temp
why must first breath be forceful
because lungs are collapsed
how are fetal kidneys different from adult kidneys
kidneys are unable to produce concentrated urine so they may become dehydrated
4 cardiovascular system changes
umbilical vessels constrict
ductus veriosus constrict
ductus arteriosus constricts
foramen ovale closes
umbilical vein
goes to the baby
umbilical artieres
leaves the baby and back to the mother
estimated time of birth
266 days
when do most women give birth
within ten-fifteen days of 266 days
how are fraternal twins made
two ovarian follicles release egg cells simultaneously and if both are fertilized , you get fraternal twins
how do twins develop from a single fertilized egg
two inner cell masses form within a blastocyst and each produce an embryo
what is a common cause of female infertility
not enough secretion of gonadotropic hormones; absence of ovulation
how can you fix female infertility? downside?
administering human chorionic gonadotropin or human menopausal gonadotropin; downside-overstimulate ovaries and cause many follicles to release secondary oocytes which may result in many births
what infections can cause infertility
STDs-inflame uterine tubes and prevent sperm entry
how does person know they are pregnant
no menstral cycle, blood vol. increases,bones may weaken, heartburn, muscle spasms
what is in vitro fertilization
when mom cannot have babies because for example moms uterine tubes were removed, couples can go through this process where doc takes oocytes and mixes them with sperm then are placed into fertilized eggs
if a woman takes an addictive substance while pregnant, what will happen to child
child will go through withdrawal symptoms. doc treats with some prescription drugs to treat anxiety.
why can vitamin c be addictive
it is not but if fetus is used to megadoses, sudden drop in level after birth could bring symptoms of deficiency
why are the vessels within the severed cord counted following birth
because if a newborn only has one umbilical artery it could be associated with other cardiovascular disorders
what is an episiotomy
a clean cut in the perineal tissues because infant passing through can tear tissues
survival of premature babies is more likely if
lungs are sufficiently developed for circulation of exchange of oxygen and carbon dioxide
what is the age a fetus is less likely not to survive
a fetus less than 24 weeks or weighing less than 600 grams
what can happen to the baby if mom is affected by german measles
ductus arteriosus fails to close completely
if PDA is not corrected surgically what will happen
blood supply is too low to supply tissues and heart may fail
chorionic villus sampling
detects birth defects
amnoicentesis
chromosome abnormality; .5% chance of a miscariage
fetal cell sorting
separates rare fetal cells from a pregnant womans bloodstream; safer because fetus isnt touched
how was fetal cell sorting discovered
autopsy on preg woman revealed cells from embryo lodged in a blood vessel in her lung. knew it was from embryo because it was a Y chromosome
thalidomide
born with flippers instead of hands and feet; didnt happen in US bc we tested it on monkeys first
rubella
german measles- mom has virus and gives to baby-baby has defects
alcohol
alter fetal brain chemistry
cigarettes
lack important growth factor- have more miscarriages and premature babies
accutane
miscarriages and defects on baby’s heart (excessive amounts of vitamin c)
workplace
breathing in bad chemicals could lead to birth defects
positives and negatives about post mortum sperm retrieval
collect sperm sample and donate to those who have difficulty having kids.
bad-not regulated on federal level; men are not considered dad- no child support
what is oxygenated in babies
umbilical veins (red)
what is not oxygenated in babies
umbilical artieries (blue)
3 tetragens that would affect baby
alcohol smoking mediciine
why do babies have a great concentration of blood than adults
more hemoglobin
why do pregnant women get morning sickness
get harmful substances out so it doesnt harm baby, should eat fruit and veggies
order
zygote blastocyst gastrula emrbyo fetus
chorionic villus sampling
detects chromosomes from chorionic villi cells; for women who is going to have a child with chromosome abnormality
fetal cell sorting
blood sample out of arm; all women have fetal cells in them so it separates fetal cells from theirs and examines cells- could be bad because it would be born with defects
