15.1 Flashcards
Fertilization
fusing the sperm and egg to form a single cell
why do few sperm arrive in the oviduct
- many die in to acidic environment on the vagina
- most go to the wrong oviduct that does not contain the ovum
is it the first sperm that fertilize the egg or no
no
the first mitosis cell division is called
cleavage division
a cell division without the enlargement of the cells is called
cleavage division
why does the cell after each cleavage division become smaller and smaller
because this cell division happens very quickly leaving the new cells no time to grow
embryonic period (2)
- tissues and organs forms
- structures that nourishes the developing embryo
fetal period (2)
- body grows rapidly
- the fully formed organs begins to function
after fertilization.. what beings to happen (1)
cleavage division
before the zygote reaches the uterus, it undergoes what
cleavage division
cleavage divion continue to happen until what
it turns into a 16 celled called morula
morula
- a zygote with 16 cells
how does blastocyst form
- when morula forms 2 cells called trophoblast and inner mass cell
blastocyst…
inner and outer layer
inner: inner mass cell (becomes the embryo)
outer: trophoblast (nourishes the embryo)
what will trophoblast turn into..
chorion
what will chorion develop into
placenta
inner mass cell will develop into..
it will develop into a embryo
what implants itself onto the endometrium
blastocyst
what it positioned against the endometrium during implantation
inner mass cell
how does implantation occur
trophoblast secretes enzymes that digest through endometrium
the embryo attaching itself onto the endometrium will..
increased SA for nutrients absorption
when does a woman is concluded to be pregnant
when the implantation is successful
when is hCG secreted
once implantation begins
what secretes hCG
- trophoblast/chorion
hCG has the same function as..
LH
- they both keep corpus luteum alive
hCG effects (4)
- maintains corpus luteum = continuous secretion of F hormones
- prevents menstruation
- maintains endometrium
- prevents spont abortion
hCG is less important during…
after 1st trimeter, when placenta is formed
amnion cavity (2)
- filled with amnionic fluid
- where the baby will develop
embryonic disk
composed of 3 layer..
- ectoderm
- mesoderm
- endoderm
gastrula
an embryo with the primary germ layers
primary germ cells
first layer of cells formed during embryogenesis
all cells, tissues, and organs are derived from what
primary germ cells through differentiation
the FORMATION of primary germ cells is called
gastrulation
the DEVELOPMENT of the primary germ cells into tissues, organs, and cells is called
differentiation
morphogenesis (2)
- forming the shape of the organs and the shape of the organism itself
- puts the cells where they need to be
morphogenesis begins with.. and depends on…
gastrulation
differentiation
neurulation
Happens in embryonic or fetal period?
happens in embryogenesis
- the process of forming the neural tube, which develops into the CNS (brain and spinal cord)
notochord develops into
skeleton
neural tube develops into..
CNS
what marks the start of organ formation
neurulation
embryo turns into fetus when…
after 8th week
when or organs and structures are formed
gastrulation is complete when..
- embryo turns into fetus
- when organs are formed
Organs start function during
Embryo turns into fetus
extra-embryonic membranes are responsible for… (4)
responsible for..
- protection
- nutrition
- respiration
- excretion
what are the extra-embryonic membranes
allantois
amnion
yolk
chorion
afterbirth
expelled …
- extra-membrionic membranes
- umbilical cord and placenta
what forms that umbilical cord (2)
allantois and yolk sac
placenta functions (3)
Nutritional: transports nutrients such as glucose, amino acids, and fatty acids; it also stores nutrients (protein, fats, carbohydrates, minerals) to be released later in the pregnancy.
Excretory: transports wastes such as urea, ammonia, and creatinine from the fetal blood to the mother’s blood.
Respiratory: transports oxygen from mother to fetus, and carbon dioxide from fetus to mother.
Endocrine: secretes hormones such as estrogen, progesterone, and human chorionic gonadotropin; allows these hormones to diffuse from mother to fetus and fetus to mother.
Immune: provides passive immunity by transporting antibodies from the mother to the fetus’s blood.
embryonic vs fetal development
embryonic
- when organs are being formed
fetal
- when organs are formed and just continue to develop
morphogenesis happens during..
embryonic period
what establish the beginnings of placenta
chorionic villi
chorionic villi
increase SA for nutrient absorption
placenta is rich with what
blood vessels
how is embryo attached to the uterine wall
through placenta
umbilical cord function
The umbilical cord contains one vein and two arteries; the arteries transport oxygen-depleted blood from the fetus to the placenta. The vein transports oxygen-rich blood to the fetus
where does primary germ cells develop from
embryonic dick from blastocyst
during neurulation.. what begins the happen
NS begins to form
what trimester is proper nutrition important
3rd
what systems are las to mature
digestive and respiratory
when is the baby highly sensitive to environmental factors (teratogens)
when it is a fetus
teratogens
any agent that causes a structural abnormality of the developing fetus due to exposure during pregnancy
what forms the placenta (2)
chronic villi
chorion
what undergoes implantation
blastocyst
where does the extra-embryonic membrane forms
trophoblast
what undergoes gastrulation to form the embryonic disk (3 primary germ layers)
inner cell mass
what undergoes morphogenesis
endoderm
what undergoes neurulation
ectodern
production of hCG decreased after
1st trimester
extra-embryonic membrane explain them
- Amnion barrier from infections Is fluid filled (amniotic fluid) > Amniotic fluid: protects the embryo (trauma, impact, cushions it, keep tempt constant=prevents tempt fluctuation)
- Yolk sac:
Produces the FIRST blood cell and the FUTURE sperm and egg cells
Serves not nutrition function, unlike other animals - Allantois
Forms the umbilical cord - Chorion
Forms placenta
Outer layer = encloses all other extra-embryonic membrane, as well as the embryo
