PRENATAL DEVELOPMENT

Chapter 5

I.Prenatal Development

Development of baby during period before birthThis is one of the most amazing concepts/gifts

God has given us here on EarthIt is absolutely astounding how people look at

the human body and prenatal development; They look it straight in the face and deny that there is a God who created it all, but instead claim in happens by accident!!

People look at a cardboard box and assume someone created it, but look at a human being and think it happened by chance.

II. Conception

A. Fertile period b/w 11th & 18th day of cycle

B. Ovulation Take place approx. 14th day 1. once each month, an ovum (female cell or egg)

is released by one of the ovaries 2. if egg meets a sperm & is then fertilized in the

Fallopian tube, conception takes place Conception – union of ovum & sperm, resulting in

pregnancy This union is called a zygote (fertilized egg) Zygote – 1st cell of life

3. If egg is not fertilized, it moves through the fallopian tube to uterus Uterus - organ where baby develops - - when egg reaches

uterus, it’s usually flushed away with menstruation bc it is no longer able to be used

III. Period of Zygote – 1st cell of life

A. lasts approx. 2 weeksB. attaches itself to lining of uterus &

begins to grow – 5 days to fully attachC. lining is needed to nourish the zygote so

the lining doesn’t shed itself = NO menstruation 1st sign of pregnancy is missed period

D. it grows by process called cell divisionE. remarkable growth takes place, yet by

end of 2 weeks, it’s still only the size of a pinhead

IV. Period of Embryo

2nd stage – developing cluster of cells in uterus during about 3rd-8th week of pregnancy

A. embryo becomes firmly attached to inner lining of uterus

B. by end of this stage, the placenta, which is the tissue that connects the sacs around the unborn baby to the mother’s uterus, develops

C. umbilical cord, long tube that connects the placenta to the unborn baby, is also developing

D. nourishment & O2 from mom’s bloodstream carried from placenta to baby through umbilical cord

E. soon embryo surrounded by bag of liquid called amniotic fluid (surrounds & protects baby during pregnancy)Actions as a cushion through minor

bumps or falls

V. Period of Fetus

Begins at 8 weeks and lasts until birthA. By beginning of this period, beginnings of

all organs and body parts 1. arms legs, facial features, internal organs, but not

ready to function yet

B. 4, 5th month1. kicks, movements, touch wall of uterus called

“quickening”

C. Heartbeat usually heard before movement feltD. Baby grows, volume of fluid increasesE. Just before delivery, fluid decreases as baby

becomes more active F. By 7th month most fetal dev. has taken placeG. Remaining months, major organs become ready to

function without help of mom’s body, baby gains weight, also stores nutrients and builds immunity to diseases and infections

H. Lightening- baby drops into birth canal1.) 1st baby- this takes place days or weeks before delivery2.) 2nd,3rd, etc.- this may happen just before labor

I. Baby nestled in pelvis, muscles of uterus and abdomen stretched

1.) can be stretched up to 60 times their orig. size and return to orig. size within a month after delivery

J. 40 weeks- Baby ready to be born! K. After birth, placenta must be delivered

Section 2- A closer look at conception

I. Genetics Package- -- passing on of character from previous generation-

physical build, skin color, hair texture and color, color of eyes, size of ears, hands, feet, blood type, some medical conditions

A. At conception, every baby receives 46 chromosomes (tiny particles in nucleus of every cell that carry hereditary char.)

1.) 23 from father’s sperm; 23 from mother’s ovum

2.) each contains thousands of genes that determine

inherited char.

3.) For every char., an individual receives 2 copies of a gene – one from mom, 1 from dad

ex. Both blue eyes -> child most likely to have blue eyes or one brown and one blue eye -> brown eye gene is the dominant factor (stronger); blue eye gene is recessive (weaker)

4.) fertilized egg is less than ½ the size of pin head – has its own genetic blueprint – AMAZING!!

B.Sex determination – at moment of conception 1. determined by special chromosome – X & Y Each ovum gives —X chrom; Each sperm gives—X or Y XX=girl, XY=boy Male determines sex of child

II. Multiple Births

A. fertilized egg divides into 2 cells & continues to divide into millions of cells

B. Sometimes growing mass of cells splits apart soon after fert. & the 2 clumps of cells continue to divide & grow into separate embryo 1. each half forms embryo – identical twins

2 babies from same egg & sperm One placenta, 2 umbilical cords

Same sex, similar characteristics

C. Fraternal twins– one egg may be released from each ovary at the same time 1. Each egg is fertilized by a diff. sperm 2. 2 placentas 3. each diff chromosomes

D. multiple births – can combination of fraternal & identical 3 eggs, 3 sperm – all fraternal Combo

III. Infertility

Inability to conceive children – 1/6A. usually fertility analysis after 1 yrB. sometimes surgery or medication may help

Meds to stimulate ovary releasing Possible multiple births Side effects – lung problems, nausea, abdominal pain

C. Sometimes male accounts for inability to conceive – low sperm count etc.

D. Good news- today half of those couples who would otherwise not be able to conceive can with med. Help

E. Medical and counseling support is needed by these couples

F. options for infertile couples 1. adoption – one of the best gifts 2. artificial insemination-

injecting father’s sperm into woman’s uterus with spec. needle (sometimes donor sperm which leads to ethical ?’s)

a.) a damaged fallopian tube = $5,000 for AI 3. in vitro fertilization –

surg. Remove egg from ovary which is placed in small glass with spec. solution and sperm added

a.) if fert. Takes place, zygote inserted in woman’s uterus b.) if it attaches itself to lining of uterus – normal preg.

4.)”Gift” – donor sperm is inserted in Fall. Tube a.) woman immobile for 3 days so zygote can travel to

uterus b.)more natural means - $8,000

5.) Ovum Transfer- “adoptive preg.” a.) egg from donor – in vitro fert. With sperm and then

implanted in uterus 6.) surrogate mother- “substitute”

A.) a woman carries and delivers a baby for a couple ALL are controversial- Is this what God intended

for procreation????

5-3 Prob. In Prenatal Dev.

I. Birth Defects- an abnormality presents at birth that affects the structure

1. premature babies- born before dev. is complete A.) less then 36 wks., weighs less then 5 ½ lbs. B.) low weight babies- born at full term, but less than 5

½ lbs. C.) need special care

2. some defects affect shape or size of body or certain parts- ex.- missing finger a.) physical birth defect

3.Others affect a part that doesn’t function properly – ex. Blindness, deafness

a.) functional birth defect4.Not all are apparent at birth, vary in severity; some can

be corrected5. Prenatal dev. Not proceeding normally often results in:

a. miscarriage -natural ending of preg. Before embryo or fetus could possible survive

b. still birth – natural ending of preg. After 20 weeks

c. grievous processes

Birth Defect Project

Create a PP on one of the following birth defects found on page 135 in your text book: Cerebral palsy Cleft lip/palate Cystic fibrosis Down syndrome Muscular dystrophy PKU Sickle-Cell Anemia Spina Bifida Tay-Sachs

Project must include:

PP CausePreventionTreatmentWhat the defect does to bodyWho usually gets itPictures

B. Causes 1. Hereditary disease/defect passed down – cleft

palate 1. environmental

a.) nutrient balance of mother’s diet b.) diseases, infections of mom during pregnancy

I. Avoiding Environmental Hazards

A. Alcohol – abstain from all alcohol, its not worth the risk FAS

Wide bridge nose Don’t like change Slow developing

B. Drugs Sudafed, tylenol, tums OK Prescription OTC drugs

No aspirin, cold med, antihistamine, especially through 3rd month

Caffeine Tobacco – low birth weight Illegal drugs – “street drugs”

Dev. Slow Born with addiction

C. X-rays – may be harmful to unborn fetusSTD’s

AIDS – attacks immune system Many others will cause birth defects or even death

Fetal testing

A. Ultra sound1. Uses sound waves to make a video image of an

unborn baby2. Skeletal or organ defects3. Due date

B. Amniocentesis Process of withdrawing a sample of the amniotic fluid

surrounding unborn baby with a special needle Test for Down Syndrome Risk of miscarriage

C. Chorionic villi sampling1. sampling small amounts of the tissue from the membrane that encases the fetus and the placenta2. go through the vagina to uterus3. villi are snipped4. tests same as amnio, but can be done earlier in pregnancy5. more than 100 birth defects can be detected prenatally