Lesson 5 and Lesson 6

Question 1

What are the three period of prenatal development?

Answer 1

1. Germinal period
2. Priced of embryo
3. Period of the fetus

Question 2

What is the time frame for the germinal period?

Answer 2

Conception to 2 weeks

Question 3

What happens during week 1?

Answer 3

-Fertilization occurs in the Fallopian tube. Soon after, cell multiplication begins, with the number of cells increasing rapidly enough that this is considered the most rapid period of growth in the lifespan.

Question 4

What i a blastocyst?

Answer 4

When theses cells begin to differentiate and gravitate toward particular positions the entire cell mass is called a blastocyst.

Question 5

What two layers are formed after about a week of conception?

Answer 5

The outer cells will form the placenta and the inner cells of the blastocyst will form the nucleus of what eventually will become the embryo.

Question 6

What is the first task of the blastocyst?

Answer 6

It is to achieve implantation. Specifically, these cells must embed themselves in the nurturing lining of the uterus. This implantation occurs about 10 days after conception.

Question 7

What is the placenta and when does it develop?

Answer 7

The placenta develops some time during the second week of the prenatal period. It grows from the outer layer of the blastocyst and attaches to the wall of the uterus.

The placenta is an organ that allows for exchanges of oxygen, nourishment, and waste products between the blood system of the pregnant woman and that of the developing organism. The placenta also controls production of hormones important to pregnancy.

Question 8

What is the time frame of the Period of the Embryo stage?

Answer 8

3-8 weeks

Question 9

What consists of the Period of the Embryo?

Answer 9

This period is marked by growth into specific body systems. It is a very important time of development because growth is very rapid and all of the organism’s vital organs are forming.
The first sign of a human body is development (by about day 14) of a thin line down the middle of the embryo (primitive streak). This will become the neural tube at 22 days, and marks the beginning of the development of the central nervous system, brain and spinal column.

Question 10

What are the two direction development proceeds in?

Answer 10

1. Cephalocaudal (head to tail) - from the top of the body downward
2. Prosimodistal (spine to extremities) - from the center fo the body outward. Thus, growth will be most rapid at the center (proximodistal) of the head (cephalocaudal).

Question 11

What happens in the 4th week of development? (Within Period of the Embryo)

Answer 11

The head takes shape as eyes, ears, nose and mouth start to form. Also, a miniscule blood vessels that will become the heart begins to pulsate.

Question 12

What happens in the fifth week of development? (Within Period of Embryo)

Answer 12

• Arm and leg buds appear
• upper arms, the forearms, then hands, then fingers develop (note proximodistal direction of development from center of body outward).
• legs, then feet, then toes develop (again this represents proximodistal development, but the fact that the legs/feet/toes envelop after the arms/hands/fingers represents cephalocaudal development.

Question 13

What goes on during the eighth week after conception (56 days)? (Period of the Embryo)

Answer 13

The embryo weighs 1/30 ounce (1 gram) and is approximately one inch long. This embryo now has all the structures/organs of the human body, except for the sex organs, which will not e fully developed until approximately the 12th week. The embryo moves frequently, about 150 times/hour, but such movement is random and imperceptible to the pregnant woman, who even at this point might not know she is pregnant. Once this juncture in the pregnancy is reached, the organism is referred to as a fetus.

Question 14

What is the time frame for the Period of the Fetus?

Answer 14

9 weeks - Birth

Question 15

What goes on during the Period of the Fetus?

Answer 15

During this period of prenatal development, the organism will grow from approximately 1/4 oz and 1” length to approximately 7lbs and 20 inches in length (average).

Question 16

What goes on during the 3rd month? (Period of Fetus)

Answer 16

In the 23rd pair of chromosomes is xY (male), a gene on the Y chromosome commands that male sexual organs develop. Without this command, the default of prenatal development is the formation of the female sexual organs.

by the 112th week, genitals are fully formed and sending hormones to the developing brain.

By the end of the 3rd month, the fetus has all body parts, weighs approximately 3 ounces and is approximately 3 inches long. Though there is a variation from fetus to fetus in terms of size and relative development, all are too small and too immature to survive out of the womb at this time.

Question 17

What happens during the 4th, 5th and 6th months?

Answer 17

• heartbeat becomes stronger and is detectable with a stethoscope
• Cardiovascular system becomes more active
• Pregnant woman feels moement (17-18 weeks)
• Digestive, respiratory and excretory systems develop; organs begin to function
• Fingernails, toenails buds for teeth form; hair grows

Question 18

What is Neurogenesis?

Answer 18

Development of many new neurons [brain cells]

Question 19

What is synaptogenesis?

Answer 19

Development of many new synapses, which are connections between neurons

Question 20

What goes on with the brain during months 4,5, and 6

Answer 20

Rapid growth and development, increasing 6 times in size. In fact, brain growth during this period is the greatest of the entire lifespan. Neurogenesis and synaptogenesis characterize this rapid growth.

Question 21

What is the Age of Viability?

Answer 21

It is the age at which a preteen newborn can survive. Currently, at 22 weeks after conception, a fetus can survive outside the moother’s uterus if specialized medical care is available.

Thus, 22weeks is the age of viability.

Question 22

What happens during the final three months?

Answer 22

Maturation of the neurological respiratory and cardiovascular systems, all of which strengthens the fetus in preparation for life outside the womb.

Weight gain in the last three months is proximity 5 ounces, which assures adequate nutrition to the rapidly developing brain. The fetus practices breathing during this tie by swallowing fluid and breathing it out.

the relationship between monsters and baby intensifies as the increasing size and movement of the fetus make the pregnant woman very aware of it. Fetus becomes aware of the sound of the mothers voice, her smell and her movements, all of which can contribute to the relationship that will develop between baby and mother following birth.

Question 23

What happens at time of Birth?

Answer 23

At approximately 266 days from conception (40 weeks from the pregnant woman’ last period or 38 weeks after conception), the fetal brain signals the release of hormones, specifically oxytocin, which initiates the process of labor as the uterus contracts at regular intervals to push the fetus out. Labor is divided into three stages.

Question 24

What is the first stage of Birth?

Answer 24

This is the longest stage of birth. Contractions lead to dilation (increased size of the opening) and shortening (effacement, or thinning) of the cervix. The average time for this stage for a first pregnancy is said to be about 8-10 hours.

Question 25

What happens during the second stage?

Answer 25

During the second stage the bby’’s head moves through the vagina nd is born, followed quickly by the shoulders and the rest of the body. The average time for this stage is said to be 1-2 hours for the first-time mother.

Question 26

What happens during the third stage?

Answer 26

The birth process does not end with the birth of the infant. In third stage of labor, blood flow through the umbilical cord must stop the placenta must detach itself from the uterine lining, and the placenta must be born.

Question 27

What is the APGAR scale?

Answer 27

A scale that focuses on five characteristics that are each evaluate on a three point scale ranging from 0-2.

Question 28

What are the five characteristics on the APGAR scale?

Answer 28

1. Heart rate
2. Respiratory effort
3. Muscle tone
4. Color
5. Reflex irritability

Question 29

What does the rating of 0-2 on he APGAR scale mean?

Answer 29

A 2 means a higher score and reflects that things are as they should be.
A low score reflect problems.

A total score of above 7 is good. A total score below 7 indicates the newborn needs assistance breathing. A total score below 4 is an emergency and requires immediate medical attention.

Question 30

Using prevention as a solution to healthy babies?

Answer 30

There is no substitute for good prenatal care. A medical professional (physician or midwife) should follow the pregnancy and provide regular check ups for the pregnant woman. In this way, many problems can be dentifrice day early and remedied before they become very serious. Additionally, the pregnant woman is much more likely to receive the information and advice she will need to take care of herself in a way that will optimize the likelihood of a healthy pregnancy and birth.

Question 31

What is Canalization?

Answer 31

This is a process characterized by rigidly defined pathways along which genes direct the development of specific characteristics. Basically, through the long course of evolution, characteristics (physical and behavioral) that have become essential to survival of the species have become canalized, which means the genes that lead to the expression of these characteristics are very likely to lead to this expression, even in the ace of environmental factors that might threaten this expression.

Question 32

What is Teratology?

Answer 32

It is the study of birth defects, and its goal is to increase the odds of normal prenatal development.

Question 33

What are teratogens?

Answer 33

These are substances, such as drugs and pollutants and conditions (e.g. severe malnutrition and extreme stress), that increase the risk of prenatal abnormalities. Teratogens can cause physical as well as learning and behavioral problems.

Question 34

What is Behavioral teratogens?

Answer 34

Behavioral teratogens are those teratogens that harm the brain, and thus impair the child’s future intellectual and emotional functioning (about 20% of children suffer from these).

Question 35

Determining Risk

Answer 35

All pregnant women in the twenty-first century will be exposed to teratogens at some point during their pregnancy. Such exposure puts the developing embryo/fetus at risk, but a number of factors determine whether teratogens exposure will lead to defects.

Several prenatal factors determine the specific level of risk, including timing dosage and genetic vulnerability; there also are known protective factors.

Question 36

What is timing?

Answer 36

Timing - Every part of the developing organism has a critical period which is a time of maximum vulnerability that occurs when cells are specializing to become specific organs, body parts, other important structures of the organism. In other words, it is the case that specific parts of the organism are most at risk when they are forming and developing most rapidly.

Question 37

Amount of exposure

Answer 37

The potential damage caused by any teratogen is relate to the amount of exposure to that teratogens.

Some teratogens are characterized by threshold effects, which means that exposure to these teratogens maybe harmless to a point, but beyond that point there will be damage.

Examples: alcohol and marijuana.
At low levels, alcohol does not cause harm to the embryo/fetus.

Question 38

Genes associated with risks

Answer 38

Although not well understood, genes are known to affect the likelihood of prenatal damage.

Question 39

Avoid known teratogen

Answer 39

It is important for pregnant women to avoid teratogens to the extent this is possible. The more informed a pregnant woman is about the potential hazards, the better able she is to protect herself and her enveloping embryo/fetus.

Question 40

The benefits of prenatal care

Answer 40

There is no better way to improve the odds of a healthy pregnancy and birth than by receiving prenatal care.

Question 41

Effective prenatal care consists of:

Answer 41

1. Protects against teratogens (such as by not prescribing dangerous medications.)
2. Typically involves a sonogram which allows for the early assessment of normal development.
3. Allows for avoidance of harm from certain diseases such as Aids
4. Affords/promotes proper nutrition.

Question 42

Nutrition as a protective factor

Answer 42

It is very important that the pregnant woman be well nourished. The average pregnant woman should gain at least 20 pounds during her pregnancy, and she should have a well rounded diet and, if recommended by her physician o midwife, should take prenatal vitamins.

Question 43

Social support and protective factors

Answer 43

Pregnant women who are happy with the level of social support they receive from those around them experience fewer complications during pregnancy and birth than do women who are not happy with the level of social support they receive.