Developmental Anatomy

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

1. contractions of myometrium force baby’s head into cervix
2. cervix stretches, causing oxytocin to be released
3. oxytocin causes myometrium to contract forcefully, pushing baby further into cervix, which causes stretching
4. 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