Maternal Week 4 Flashcards
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
The earliest age at which fetuses survive if they are born is generally accepted as 24 weeks or at the point a fetus weighs more than 500-600 g.
AGE OF VIABILITY
The earliest age at which fetuses survive if they are born is generally accepted as _________ or at the point a fetus weighs more than ________
24 weeks
500-600 g
(also referred to as conception and impregnation) is the union of an ovum and a spermatozoon.
Fertilization
outer third of a fallopian tube, termed the
ampullar portion.
Semen ejaculation average
2.5ml of fluid containing 20 to 200 million spermatozoa per milliliter
The placenta and the membranes, which will serve as the fetal
lungs, kidneys, and digestive tract
hormone secreted by the trophoblast cells.
human chorionic gonadotropin (hCG)
The endometrium is now termed the _______ (the Latin word for _______
Decidua
Falling off
decidua has three separate areas
Decidua basalis
Decidua capsularis
Decidua vera
the part of the endometrium that lies directly under the embryo (or the portion where the trophoblast cells establish communication with maternal blood vessels)
Decidua basalis,
the portion of the endometrium that stretches or encapsulates the surface of the trophoblast
Decidua capsularis,
the remaining portion of the uterine lining. As the embryo continues to grow, it pushes the decidua capsularis before it like a blanket.
Decidua vera,
As early as the 11th or 12th day, miniature villi that resemble probing fingers, termed______________, reach out from the single layer of cells into the uterine endometrium to begin formation of the placenta.
chorionic villi
A double layer of trophoblast cells surrounds these.
syncytiotrophoblast, or the syncytial layer.
cytotrophoblast or Langhans’ layer
is present as early as 12 days’ gestation.
This layer of cells disappears, however, between the 20th and 24th weeks.
cytotrophoblast or Langhans’ layer
• This layer of cells produces various placental hormones, such as hCG, somatomammotropin (human placental lactogen [hPL]), estrogen, and progesterone
syncytiotrophoblast, or the syncytial layer.
Latin for “pancake,” which is descriptive of its size and appearance at term
placenta
• Its growth parallels that of the fetus, growing from a few identifiable cells at the beginning of pregnancy to an organ _____________cm in diameter and __________ cm in depth, covering about half the surface area of the internal uterus at term
15-20
2-3
As early as the 12th day of pregnancy, maternal blood begins to collect in the intervillous spaces of the uterine endometrium surrounding the chorionic villi.
Circulation
the rate of uteroplacental blood flow in pregnancy increases from about
50 mL/min at 10 weeks to 500 to 600 mL/min at term.
The first placental hormone produced, can be found in maternal blood and urine as early as the first missed menstrual period (shortly after implantation has occurred) through about the 100th day of pregnancy.
Human Chorionic Gonadotropin.
this is the hormone analyzed by pregnancy tests
Human Chorionic Gonadotropin.
is to act as a fail-safe measure to ensure that the corpus luteum of the ovary continues to produce progesterone and estrogen.
hCG
(primarily estriol) is produced as a second product of the syncytial cells of the placenta.
Estrogen
contributes to the woman’s mammary gland development in preparation for lactation and stimulates uterine growth to accommodate the developing fetus.
Estrogen
is often referred to as the “hormone of women”; progesterone as the “hormone of mothers.”
Estrogen
This hormone also appears to reduce the contractility of the uterus during pregnancy, preventing premature labor.
maintain the endometrial lining of the uterus during pregnancy
Progesterone
a hormone with both growth-promoting and lactogenic (milk-producing) properties.
• hPL
It is produced by the placenta beginning as early as the sixth week of pregnancy, increasing to a peak level at term. It can be assayed in both maternal serum and urine.
hPL