umbilicus
the area where the cord was attached that becomes covered by a thin layer of skin
ectoderm
forms nervous tissue and skin
amniocentesis
prenatal diagnosis test used to detect fetal abnormalities by analyzing fetal cells found in amniotic fluid
surfactant
the substance alveolar cells produce which aid in lug development
mucus plug
discharge that signals the start of true labor
alpnafetoprotein
one of the two substances that could indicate problems with nervous system development
lanugo
the fine, soft hair that covers the skin of the baby during development
oxytocin
hormone that stimulates the contraction of the myometrium of the uterus during labor
inner cell mass
differentiates into 3 primary germ layers; the ectoderm, the mesoderm, and endoderm
transition
the phase of labor characterized by intense contractions every 20 minutes that last 60-90 seconds
placenta
site of exchange of nutrients and waste between mother and fetus
blastocyst
hollow sphere of cells that enters the uterine cavity
trophoblast
outer covering of cells of the blastocyst
latent labor
this phase is in the stage of dilation; characterized by contractions every 5-20 min and a cervical dilation of 6 cm
prostaglandins
enzymes that break down collagen fibers in the cervix, which causes it to soften
Mullerian ducts
ducts that develop into female reproductive system
chorion
membrane derived from the trophoblast; becomes the principal embryonic part of the placenta and produces HCG
umbilical cord
vascular connection between the mother and the fetus
cleavage
early divisions of the zygote
SRV gene
the gene that sets into motion the development of a male
fetus
the developing individual from the 3rd month of pregnancy until birth
identical
type of twins that develop from a single fertilized ovum that separates into two embryos
embryo
the developing individual up until the first two months after fertilization
4 ways the mother changes due to pregnancy
-pressure on the stomach forces contents into esophagus, causing heartburn
-lower back pain
-dyspnea (difficulty breathing)
-changes in skin; stretch marks, dark eyes and linea alba of abdomen
-weight gain due to fetus, amniotic fluid, placenta, uterine enlargement, and breast enlargement
positive feedback loop of labor
contractions of myometrium force baby’s head into cervix
cervix stretches, causing oxytocin to be released
oxytocin causes myometrium to contract forcefully, pushing baby further into cervix, which causes stretching
positive feedback stops with birth
yolk sac
forms 12 days after fertilization and functions as an early site of blood formation
amnion
forms 8 days after fertilization and surrounds the embryo creating a cavity that becomes filled with amniotic fluid which protects the embryo, helps regulate fetal temperature, and prevents adhesions between the skin of the fetus and surrounding tissues
allantois
vascular structure that serves as an early site of blood formation