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