conception and fetal development(1)

7/25/2019 Conception and Fetal Development(1)

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Conception and FetaConception and FetaDevelopmentDevelopment

NUR 324.60 Nursing Management of Childbearin

FamiliesOctober 0! 204

Nanc" Mur#h"! RN! M$N

%h& Candidate


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Objectives At the end of the student will be able to: Describe the process of fertilization and implantatio Describe the development, structure, and functions

placenta during intrauterine life. Discuss key concepts related to fetal development. Describe in order of increasing compleity the struc

that form during the cellular multiplication anddi!erentiation stages of intrauterine development.

"ummarize the signi#cant changes in growth anddevelopment of the embryo and fetus at $, %, &', &%'), *', *%, and *) weeks after conception.

+dentify the vulnerable periods during fetal developwhich malformations of the various organ systems moccur, and describe the resulting congenital malform


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Key Concepts and Terms

Chromosomes -enetics -ametogenesis, /ogenesis,

"permatogenesis

0itosis

0eiosis

1he 2rocess of Fertilization

2reparation for Fertilization1he 0oment of Fertilization

2re3embryonic "tage

Cellular 0ultiplication

+mplantation

Cellular Di!erentiation

Development and Functio2lacenta

2lacental Circulation

2lacental Functions

Function of Amniotic Fluid

4mbryonic and Fetal Deve

4mbryonic "tage

Fetal "tage

Factors +n5uencing 4mbryFetal Development


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Setting the Stage: FemaleSetting the Stage: FemaleReproductive CycleReproductive Cycle

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Setting the Stage: FemaleSetting the Stage: FemaleReproductive CycleReproductive Cycle

F40A4 7427/D6C1+94 C


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Figure 32a Sperm penetration of an ovum. The sequential steps of oocyte penetration by a

moving from top to bottom. Source: Scanning electron micrograph from Nilsson, L. (1990).

New York: Dell Publishing.


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Setting the Stage: the CelluSetting the Stage: the CelluLevelLevel

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Figure 31b Each spermatogonium produces four haploid spermatozoa.


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ConceptionConception

A se=uential process: -amete for/vulation, Fertilization

Following ovulation, fertilization ofallopian tube

Cell division occurs in the zygoteFlows into uterus


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Intrauterine evelopment:Intrauterine evelopment:Three StagesThree Stages "tage +: 2re34mbryonic: Fertilization 333&$ days

C!LL"L#R $"LTI%LIC#TIO&C4A9A-40/76A>A"1/C


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Intrauterine evelopmenIntrauterine evelopmen


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%re'!mbryonic Stage%re'!mbryonic Stage

Fertilized egg not yet implanted in the

6pon initial cell division the fertilized ebecomes a'"gote

At approimately &'3&$ days followingfertilization, zygote is implanted in the of the uterus

Cells specialize into what will become o


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%re'!mbryonic Stag%re'!mbryonic Stag

0orula >lastocys


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I$%L#&T#TIO&I$%L#&T#TIO&


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I$%L#&T#TIO&I$%L#&T#TIO&(')* #+S a,ter(')* #+S a,ter

Fertili-ationFertili-ation


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I$%L#&T#TIO&I$%L#&T#TIO&

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Figure 37 Early development of primary embryonic membranes. At 412 weeks, the decidua cap

portion enclosing the embryo on the uterine surface) and decidua basalis (placental portion encom

elaborate chorionic villi and maternal endometrium) are well formed. The chorionic villi lie in blo

intervillous spaces within the endometrium. The amnion and yolk sac are well developed. Source:

Marieb, E. N. (1998).


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!mbryonic Stage

Di!erentiation of tissues into what wbecome organs organogenesisCritical period of pregnancy in that organogenesis occurs, anomalies caresult in miscarriage

6mbilical cord and placenta developprovide nutrition and oygen to andremove waste from the embryo

Developmental patterns:Cephalocaudal 2atterns

2roimodistal 2atterns


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Fetal StageFetal Stage All organsBbody systems in place

/rganogenesis is complete. Characterized by rapid body growth andi!erentiation of body tissues.

At approimately * months, genitalia can beidenti#ed

At approimately $ months, movements can be by the motherAt approimately months fetus may be viablecan survive outside the womb with nutrition antemperature regulation support.


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#ge#ge

Fertilization age947"6"

-estational age commonly used in practice: FerAge ' Geeks

Full term H *% to $( weeks of fertilization age or *) tweeks of gestational ageafter last menstrual period


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Critical %eriods duringCritical %eriods duringevelopmentevelopment

2oints at which key transitions occur tenbe the most criticalAttachment to the uterine wall/rganogenesis tends to most vulnerama@or malformations.E 2re34mbryon

into early 4mbryonic "tagesChronic eposure to toins during fetstage linked to delay in fetal growth ade#cits in intellectual potential fetal

%eriods o, Critical%eriods o, Critical


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%eriods o, Critical%eriods o, Criticalevelopments .based onevelopments .based on

Fertili-ation #ge/Fertili-ation #ge/


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Factors In0uencing FetaFactors In0uencing Fetaevelopmentevelopment

Circulation1eratogens

0aternal 7isk factors 2re3eisting medical conditions

+nfections -estational disorders 0aternal 8utrition Family history


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The Father1s Role in FetaThe Father1s Role in Fetaevelopmentevelopment

;ealth of "permItoins, radiationdrugs and alcohol

"upportive partnerIemotionalsupport, support for alcohol J tob

free pregnancy"upport and encourage access tohealth care


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Figure 310 Vascular arrangement of the placenta. Arrows indicate the direction of blood flow. M

through the uterine arteries to the intervillous spaces of the placenta and returns through the uterine

circulation. Fetal blood flows through the umbilical arteries into the villous capillaries of the placen

through the umbilical vein to the fetal circulation.


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"$3ILIC#L COR"$3ILIC#L COR

>y the #fth week of embryonic development, theumbilical cord has formed.

1wo arteries and one vein A393A

GhartonKs Lelly


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"$3ILIC#L COR #3&OR$#"$3ILIC#L COR #3&OR$#

(elamentous insertion of umbilical cord


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F!T#L CIRC"L#TIO&F!T#L CIRC"L#TIO&

;igh pulmonary vascular resistance

1ransient structures &uctus )enosus

Foramen o)ale

&uctus arteriosus

https:BBwww.youtube.comBwatchMvHuwswhoNfkm0


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$"LTIF!T#L %R!4&CI!$"LTIF!T#L %R!4&CI!

https:BBwww.youtube.comBwatchMvHOetwC*wd

conception and fetal development(1)

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