pregnancy, growth and development Flashcards
a secondary oocyte and a spermatozoon form a zygote that prepares for cell division
fertilization
a group of blastomeres created by cleavage divisions
pre-embryo
occurs when the blastocyst adheres to and then becomes enclosed within the uterine lining about 7 days after fertilization
implantation
the stage of development that results from the cleavage
morula
consists of an outer trophoblast and an inner cell mass; stage begins once the zygote arrives in the uterine cavity
blastocyst
the outer layer of cells, which separates the outside world from the blastocoele and provides nutrients to the developing embryo
trophoblast
begins as a layer of cells spread out around the outer edges of the blastocoele to form a complete pouch; forms from endoderm and mesoderm, it is an important site of blood cell formation
yolk sac
begins as cells from the blastodisc migrate around a cavity that separates the inner cell mass from the trophoblast; forms from ectoderm and mesoderm, it encloses the fluid that surrounds and cushions the developing embryo and fetus
amnion
fluid contained in the amniotic cavity that surrounds and cushions the developing embryo or fetus
amniotic fluid
begins as an outpocketing of the endoderm near the base of the yolk sac; base gives a rise to the urinary bladder; forms from endoderm and mesoderm
allantois
forms the interface between fetal and maternal systems
placenta
name the 4 extra-embryonic membranes
- yolk sac
- amnion
- allantois
- chorion
forms from mesoderm and trophoblast; it surrounds the blastocoele
chorion
the connecting stalk between the fetus and the placenta
umbilical cord
deoxygenated blood that flows to the placenta
umbilical artieries
produced by the placenta, softens the pubic symphysis and dilates the cervix
relaxin
begins with the onset of true labor, as the cervix dilates and the fetus begins to move toward the cervical canal
dilation stage
begins as the cervix dilates completely and continues until the fetus has completely emerged from the vagina
expulsion stage
the uterus gradually contracts, tearing the connections between the endometrium and the placenta and ejecting the placenta
placental stage
maintains corpus luteum; keeps producing progestron. stimulates placenta and prevents immune system from rejecting foreign cells
HCG
what are the last two organ systems to mature
respiratory and digestive
first milk baby receives from mom
colostrum
oil from sebaceous glands
sebum
inhibits uterus from contracting FSH and LH which starts to decrease progesterone over time which increase proctic gland so uterus starts to contract
progesterone
comes from corpusluteum
progesterone and estrogen
as placenta matures we get more of this and help with contractions and widening of the vagina
estrogen
comes from corpus luteum, relaxs the uterus and pelvis (birth canal)
relaxin
hormone from pituitary gland that stimulates uterus causes uterus to contract putting more pressure on cervix
oxytocin
forceable explosion of the fetus
parturition
triggers uttering contraction (oxytocin)
pituitary hormone
the gradual modification of anatomical structures and physiological characteristics during the period from fertilization to maturity
development
first two months after fertilization
embryological development
begins at the start of the ninth week and continues until birth
fetal development
during this period the rudiments of all the major organ systems appear
first trimester
development of organs and organ systems, the body shape and proportions change; by the end of this trimester, the fetus looks distinctively human
second trimester
the largest gain in fetal weight, major organ systems become fully functional
third trimester
begins at birth can continues to maturity
postnatal development
the state of full development or completed growth
maturity
the cytoplasm of the zygote becomes subdivided among an ever-increasing number of progressively smaller blastomeres
cleavage
begins with the attachment of the blastocyst to the endometrium of the uterus
implantation
migrate along the walls of the amniotic cavity and separate the amniotic cavity from the trophoblast. first step in the formation of the amnion
blastodisc
absorbs and distributes nutrients released into the blastocoele by the trophoblast
yolk sac
migration of mesoderm around the inner surface of the trophoblast creates this
chorion
mesodermal migration around the outside of the amniotic cavity form what
amnion
mesodermal migration around the endodermal pouch creates what
yolk sac
when the cervix dilates and the fetus begins to shift toward the cervical canal
dilation stage
the cervix completes its dilation
expulsion stage
muscle tension builds the walls of the partially empty uterus, the uterine contraction tears the connection bw the endometrium and the placenta or afterbirth is ejected
placental stage
