unit3 Flashcards
(30 cards)
What are the three main periods of prenatal development?
Germinal period, embryonic period, and fetal period.
What happens during the germinal period?
Fertilization occurs, the zygote undergoes mitosis to form a blastocyst, and implantation in the uterus occurs (first 14 days).
What is the trophoblast, and what does it become?
The outer layer of the blastocyst that forms structures responsible for nutrition and protection, including the placenta.
What marks the beginning and end of the embryonic period?
It begins at implantation (~14 days after fertilization) and ends at the 8th week post-fertilization.
What are the three layers of the embryonic disc, and what do they develop into?
- Ectoderm: Nervous system, skin, hair
- Mesoderm: Muscles, bones, cardiovascular system
- Endoderm: Digestive system, lungs, internal organs
What is the function of the placenta?
It allows the exchange of oxygen, nutrients, and waste between the mother and the embryo.
When does the fetal period begin and what defines it?
It begins at the 9th week post-fertilization and is marked by rapid growth and organ system maturation.
What is the age of viability?
Around 22 to 24 weeks (5½ to 6 months), when a fetus may survive outside the womb with medical assistance.
What is the cephalocaudal development pattern?
Development proceeds from head to toe, with the head forming before the rest of the body.
What is the proximodistal development pattern?
Growth starts at the center of the body and moves outward to limbs and extremities.
What are teratogens?
Harmful agents (e.g., drugs, alcohol, viruses) that can cause birth defects or developmental issues.
What is the sensitive-period principle regarding teratogens?
The severity of damage depends on when exposure occurs; the embryonic period (3-8 weeks) is the most vulnerable.
What is the dosage principle in teratology?
The higher the dose or the longer the exposure to a teratogen, the greater the risk of harm.
What is Fetal Alcohol Syndrome (FAS)?
A condition caused by prenatal alcohol exposure leading to physical and cognitive abnormalities, such as microcephaly and attention deficits.
What are the effects of smoking during pregnancy?
It can cause low birth weight, respiratory problems, and an increased risk of miscarriage.
What is the Thalidomide tragedy?
A drug used in the 1960s for nausea in pregnancy caused severe limb deformities in babies when taken during early pregnancy.
What is Rubella’s effect during pregnancy?
If contracted during the first trimester, it can cause congenital blindness, deafness, and intellectual disabilities.
What is amniocentesis?
A prenatal test where a needle extracts amniotic fluid to detect genetic abnormalities.
What is chorionic villus sampling (CVS)?
A prenatal test that takes a sample from the placenta to detect genetic conditions, done earlier than amniocentesis.
What is the Apgar Scale used for?
A quick test after birth assessing newborns’ color, heart rate, reflexes, muscle tone, and respiratory effort.
What are the three stages of birth?
- Stage 1: Contractions and dilation of the cervix
- Stage 2: Baby moves through the birth canal
- Stage 3: Expulsion of the placenta
What is a breech birth?
When a baby is born feet or bottom first instead of head first, increasing the risk of complications.
What is the Moro reflex?
A primitive reflex where a newborn flings out its arms in response to a loud sound or sudden movement.
What is the rooting reflex?
When a newborn turns its head toward a touch on the cheek, helping them find the breast for feeding.
