CH. 15 The use of ultrasound in the first trimester
gestational age (menstrual age)
duration of pregnancy counted from the first day of the last menstrual period, expressed in weeks and days or fractions of weeks
blastocyst
early gestation consisting of a thin outer layer of cells (trophoblast ), a fluid filled cavity, and an inner cell mass (embryo blast)
Fetal stage begins following ________ period after about ___________
embryonic 11 weeks
The blastocysts inner cell mass differentiates into two layers: thick __________ adjacent to the trophoblast, and thin __________ facing the blastocele
epiblast hypoblast
The placenta will mature from early pregnancy to release these 3 things
estrogen, hCG, progesterone
What 3 things assist the ova to move into and through the fallopian tube
fimbriae, cilia, contractile walls
LMP
first day of last menstrual period
The developing cluster of cells travels through the fallopian tube and reaches the uterus about _______ days after fertilization
four
estrogen
group of hormones, primarily produced in the ovaries, which effect secondary sex characteristics and the menstrual cycle
gametes are ________ cells with _________ chromosomes
haploid 23
progesterone
hormone produced by the corpus luteum in the ovary and the placenta of pregnant women
follicle stimulation hormone (FSH)
hormone produced in the anterior pituitary, which stimulates the maturation of ovarian follicles
The ________ hormone triggers ovulation
luteinizing
spermatozoon (pl. spermatozoa)
male gamete
crown-rump length
measurement of the lowest axis of an embryo determines gestational age
chorion
membrane around the chorionic cavity, made up of trophoblast cells and extra embryonic mesoderm
amnion
membrane enclosing the amniotic cavity and embryo or fetus
The whip like tails of sperm contain______
mitochondria
A cluster or ball of forming cells is a :
morula
gravidity
number of times a woman has been pregnant
fertilization
penetration of an oocyte by a sperm to form a diploid zygote
corpus luteum
progesterone-secreting structure formed by a follicle after releasing its oocyte
The five brain vesicles, which will become the lateral ventricles, third ventricle, and the upper and lower parts of the fourth ventricle, and the connections between them develop from :
prosencephalon and rhombencephalon
The first visualized structure within the gestational sac is the :
secondary yolk sac
zygote
single cell resulting from the fusion of two gametes
parity
summary of a woman pregnancy outcomes. The most common description of parity is expressed in 4 numbers. 1= term deliveries 2= preterm deliveries 3= abortions 4= living children
First blood cells to the embryo are produced by the ___________ and are transferred to and fro through the ___________ veins and arteries
umbilical vessel vitelline
What prevents more than one sperm entering an ovum?
zona pellucida
nourishment from the endometrial glands cross the ________ and enter the _______
zona pellucida morula
The head of the sperm cells contains ____________ which house enzymes allowing for penetration of the outer layer of the ovum
acrosome
At what age have the rudimentary forms of all embryonic organs and structures developed
almost 11 weeks menstrual/gestational age
fertilization generally occurs in the ______ portion of the fallopian tube
ampullary
The two endometrial layers are a thin __________ layer adjacent to the myometrium and a functional layer of __________
basal connective tissue
A blastocyst consists of what 3 things?
blastocele , trophoblast, embryoblast
The double sac sign is developed by two layers of deciduas, ________ and _________
capsularis parietals
decidualization
changes in the endometrium to allow implantation of blastocyst
The first structure seen sonographically within the uterus in early pregnancy is:
chorionic sac
fetal placenta occupies the _________ portion of the endometrium, leaving the basal layer intact
decidua basalis
The portion of the endometrium that surrounds the blastocyst
decidua capsularis
preparatory changes in the endometrium allowing for implantation
decidualization
The yolk sac becomes part of the embryonic gut and contributes to:
digestive, respiratory and urogenital development
Sonography may detect a blastocyst embedded in the decidua as early as __________ after conception:
11 days
The normal resting heart rate of a third trimester fetus is:
110-160 bpm
spontaneous pregnancy loss usually happens in the :
1st trimester
the primitive fetal heart begins beating about __________ days after conception
23
___________ hours after fertilization, rapid cell division occurs and is knows as __________
24-30 cleavage
A normal gestation last approx. :
280 days
The embryonic disc contains ________ germ cell layers from which all future organs and tissue is derived
3
acrosome
Area located in the head of the sperm containing enzymes to aid in penetration of the oocyte
Mean Sac Diameter (MSD)
Average diameter of the gestational sac, used to determine gestational age
The most accurate measurement for dating in early pregnancy is the:
CRL
conceptual age
Duration of pregnancy, counted from fertilization (conception), expressed in hours or days. Also called embryonic age or postovulatory age
Ultrasound in the first trimester is mostly performed to demonstrate :
EDD and GA
gestational sac
First sonographic evidence of an intrauterine pregnancy, the fluid-filled blastocyst
When the nuchal translucency measurement is combined with ___________, the detection rate for trisomy 21 increase to 86%
PAPP-A and free B-hCG
conceptus
Product of fertilization, including all stages from zygote to fetus
pregnancy associated plasma protein A (PAPP-A)
Protein produced by the trophoblasts; abnormal levels of PAPP-A may be associated with an increased risk of chromosomal abnormalities
morula
Solid cluster of undifferentiated cells formed by repeated cleavage of the single cell that resulted from the fusion of two gametes
The implantation window is _______ days after ovulation and lasts approx. _________ days
6-8 4
luteinizing hormone (LH)
A hormone produced by the anterior pituitary gland that triggers ovulation.
yolk sac (umbilical vesicle)
A structure within the cavity of the blastocyst that provides nourishment to the embryo and produces its first blood cells. The secondary umbilical vesicle (yolk sac) is the first structure to be sonographically identified within the gestational sac.
aneuploidy
Abnormal number of chromosomes.
chorionic villi
Budlike outward growths from the trophoblast, some of which give rise to the fetal portion of the placenta
estimated date of delivery (EDD)
Due date, calculated by adding 280 days to the first day of the last menstrual period; also called estimated date of confinement (EDC)
human chorionic gonadotropin (hCG)
Hormone produced by trophoblast cells of the blastocyst, which extends the life of the corpus luteum in the ovary; most pregnancy tests are based on detection of hCG
nuchal translucency (NT)
Subcutaneous fluid in the posterior region of the neck of embryos and fetuses up to 14 weeks' gestational age; abnormally large NTs have been associated with a higher risk of chromosomal and structural abnormalities