Maternal prelim Flashcards
(first 2 weeks, beginning with fertilization)
Pre-embryonic
(weeks 3 through 8)
Embryonic
(from week 8 through birth)
Fetal
From ovulation to fertilization
Ovum
From fertilization to implantation
Zygote
From implantation to 5–8 weeks
Embryo
From 5–8 weeks until term
Fetus
Developing embryo and placental structures throughout pregnancy
Conceptus
(also referred to as conception and impregnation)
Fertilization
is the union of an ovum
and a spermatozoon.
Fertilization
where fertilization usually occurs
in the outer third of a fallopian tube, termed
the ampullar portion.
after penetration of the ovum, the chromosomal material of the ovum
and spermatozoon fuse to form a
zygote.
ring of mucopolysaccharide fluid
(the zona pellucida)
circle of
cells
(the corona radiata).
is released by the spermatozoa and
dissolves the layer of cells protecting the ovum.
Hyaluronidase (a proteolytic enzyme)
The cells in the outer ring are
trophoblast cells.
contact between the growing structure and the uterine
endometrium, occurs approximately 8 to 10 days after fertilization.
Implantation,
Once implanted, the zygote is called an
embryo.
grows from a few identifiable trophoblastic cells at the beginning of pregnancy to
an organ 15 to 20 cm in diameter and 2 to 3 cm in depth,
The placenta
“hormone of women,”
Estrogen
“hormone that maintains pregnancy.”
progesterone
is produced as a second product of the syncytial cells of the
placenta.
Estrogen
is a hormone with both growth-promoting and lactogenic
Human Placental Lactogen
It is produced by the placenta beginning as early as the sixth week of
pregnancy,
Human Placental Lactogen
is a dual-walled sac with the chorion as the outmost part
amniotic
membrane
The chorionic villi on the medial surface of the trophoblast gradually thin
until they become the
chorionic membrane,
it produces a phospholipid that initiates the formation of prostaglandins,
which may be the trigger that initiates labor.
(the amniotic
membrane)
fetus is unable to swallow
(esophageal atresia or
anencephaly
excessive amniotic fluid
hydramnios
may also
occur in women with diabetes because hyperglycemia causes excessive fluid shifts into
the amniotic space
hydramnios
a reduction in the amount of amniotic fluid.
oligohydramnios
may also
occur in women with diabetes
Hydramnios
to shield the fetus against pressure
or a blow to the mother’s abdomen.
amniotic fluid
is formed from the fetal membranes, the amnion and chorion, and provides a circulatory pathway that connects the embryo to the chorionic villi of the
placenta.
umbilical cord
(carrying blood from the placental villi to
the fetus)
umbilical cord vein
(carrying blood from the fetus back to the placental villi).
umbilical cord two arteries
The walls of the umbilical cord arteries are lined with
smooth muscle.
During the first 4 days of life, zygote cells are termed
totipotent stem cells,
become specific body cells, such as nerve, brain, or skin cells,
pluripotent stem cells.
In yet another few days, the cells grow so specific they are
termed
multipotent,
As soon as conception has taken place, development proceeds in a
cephalocaudal
(head-to-tail) direction;
the blastocyst already has differentiated to a point at
which three separate layers of these cells are present:
the ectoderm, the endoderm, and
the mesoderm
Central nervous system (brain and spinal cord)
Peripheral nervous system
Skin, hair, nails, and tooth enamel
Sense organs
Mucous membranes of the anus, mouth, and nose
Mammary glands
Ectoderm
Supporting structures of the body (connective tissue, bones, cartilage,
muscle, ligaments, and tendons)
Upper portion of the urinary system (kidneys and ureters)
Reproductive system
Heart, lymph, and circulatory systems and blood cells
Mesoderm
Lining of pericardial, pleura, and peritoneal cavities
Lining of the gastrointestinal tract, respiratory tract, tonsils,
parathyroid, thyroid, and thymus glands
Lower urinary system (bladder and urethra)
Endoderm
All organ systems are complete, at least in a rudimentary form, at ___ gestation
8 weeks (the end of the embryonic period).
the growing structure is most vulnerable to invasion by teratogens
organogenesis (organ
formation),
one of the first systems to become functional in
intrauterine life.
cardiovascular system
forms as early as the
16th day of life and beats as early as the 24th day.
cardiovascular system
sympathetic
nervous system matures,
28th week of pregnancy,
consistent heart rate of fetus
110 to
160 beats/min
This blood enters
the fetus through the
umbilical vein
umbilical vein (which is still called a vein because?
because the direction of the blood is toward the fetal heart).
Specialized structures present in the fetus then shunt blood flow to first supply the most
important organs of the body:
the liver, heart, kidneys, and brain.
Blood flows from the
umbilical vein to the
ductus venosus,
an accessory vessel that discharges oxygenated
blood into the fetal liver, and then connects to the fetal inferior vena cava so oxygenated
blood is directed to the right side of the heart.
ductus venosus,
an opening in the atrial septum called the
foramen
ovale.
the larger portion of even this blood is shunted away from the lungs through
an additional structure,
ductus arteriosus,