Chapter 2 - Prenatal Development, Pregnancy and Birth
How long is the germinal stage?
1-3 weeks
Describe the embryonic stage
1. The neural tube is formed. 2. The embryo develops by through 3 basic sequences: a. Proximodistal Sequence - Development from interior parts outward b. Cephalocaudal Sequence - Development from head to toe c. Mass-to-specific Sequence - Development of large structures before detailed structures.
Describe the Germinal stage.
1. The zygote makes its first cell division within 36 hours. It continues to divide as it travels down the fallopian tube. 2. The cluster of cells becomes a blastocyst. 3. The blastocyst imbeds itself in the uterine wall in the process of implantation. The uterus prepares itself to receive the cell mass. The outer layer of the blastocyst develops projections. At day 9, these projections burrow into the uterine wall. Blood cells proliferate, creating the placenta.
How long does the "pushing" phase of labor typically last?
30 minutes
What is a healthy apgar score?
7-10
Very low birth weight
A birth weight of 3.25 lbs or less.
Low birth weight
A birth weight of 5.5 lbs.
chorionic villus sampling
A relatively risky first trimester test for fetal genetic disorders.
neural tube
A structure formed along the back of the embryo that develops into the central nervous system.
Apgar scale
A test given after birth to assess the baby's condition. It is scored from 1-10. A score of 7 or above means the baby is in good shape.
Ultrasound
An imaging tool used to date the pregnancy and assess fetal growth.
Overweight mothers have a greater risk of having high blood sugar levels. This can lead to all of the following EXCEPT: A: high blood pressure. B: preeclampsia. C: gestational diabetes. D: still birth.
D: still birth.
In vitro fertilization
Infertility treatment in which conception occurs outside the womb. The developing cell mass is then inserted into the woman's uterus so that pregnancy can occur.
mass-to-specific sequence
Large structures before detailed structures
When startled by a loud noise or sudden movement, infants throw their heads back, fling their arms and legs out, and then pull them in. Which reflex is this?
Moro
Progesterone
The hormone responsible for maintaining pregnancy
Amniocentesis
The insertion of a syringe into the uterus to extract amniotic fluid, which is tested for a variety of genetic and chromosomal conditions.
cell mass
The mass of cells inside the embryo that will eventually give rise to the structures of the fetus
Implantation
The process by which the zygote attaches to the uterine wall
Ovulation
The process of releasing a mature ovum into the Fallopian tube each month
Fertilization
The union of the sperm and egg beginning at ovulation
ovum
egg
At what stage does every major body structure begin to form?
embryonic period
Zygote
fertilized egg
At what stage do humans first begin to be able to hear and see?
fetal stage
At what stage does the brain form?
fetal stage
Cephalocaudal
from head to tail
cervix
opening at the lower end of the uterus
Uterus
organ of the female reproductive system in which a fertilized egg can develop
Placenta
organ that nourishes the fetus
What is the correct sequence of events in conception?
ovulation, fertilization, zygote, blastocyst, implantation
Substances that are harmful to a developing embryo and fetus are known as __________.
teratogens
proximodistal sequence
the developmental principle that growth occurs from the most interior parts of the body outward
Blastocyst
the hollow sphere of cells formed during the germinal stage in preparation for implantation
Teratogens
threats to the developing baby
Are the effects of teratogens predictable or unpredictable?
unpredictable
Third trimester symptoms
• Backaches • Leg cramps • Numbness and tingling • Heartburn • Insomnia • Anxiety
Examples of teratogens
• Drugs, alcohol, tobacco • Diseases • Medication • Environmental hazards • Stress • Genetic diseases
Second trimester symptoms
• Quickening - the sensation of the baby kicking • Expansion of the uterus • Beginning of connection with the baby
First trimester symptoms
• Release of progesterone • Morning sickness • Fatigue and nausea • 1 in 10 end in miscarriage