1. Prenatal Growth from Conception to Birth
Fetal Development
Prenatal Growth from Conception to Birth
These are my notes
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Fetal Development

2. Outline of Topics Conception •Sperm •Ovum
Zygotic Period •Conception - 1st week
Embryonic Period •2nd week - 2nd month
Early Fetal Period •3rd - 6th month
Later Fetal Period •7th - 9th month/birth
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Fetal Development

3. Key Terms Conception Sperm Ovum Zygote Mitosis Embryo Ectoderm
Mesoderm
Endoderm
Congenital Malformations
Fetus
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Fetal Development

4. Conception
Conception occurs when the sperm meets and penetrates the ovum, or egg
Also known as fertilization
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Fetal Development

5. Sperm Sperm is the male reproductive cell Chief Characteristics:
Tightly packed tip (acrosome) that contains 23 chromosomes that carry genetic information
Short neck region
Trail to propel it in its search for the ovum
Microscopic
One of the smallest cells in the male body
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Fetal Development

6. Sperm Facts
Remains capable of fertilizing egg for hours after ejaculation
Of 200 million sperm that enter the vagina, only about 200 survive the journey to the fallopian tubes, where fertilization occurs
Males, at birth, have in their testes those cells that will eventually produce sperm
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Fetal Development

7. Ovum (Egg) The ovum is the female reproductive cell
Chief Characteristics:
Round
.01 mm in diameter
Consistency of stiff jelly
Contributes 23 chromosomes
Barely visible to the naked eye
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Fetal Development

8. Ovum (Egg) Facts Females already have 1-2 million primal eggs at birth
Eggs usually fertilized about 12 hours after discharged from the ovary or they die within hours
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Fetal Development

9. Zygotic Period (Conception - 1st Week)
A zygote is a fertilized egg with 46 chromosomes
Genetic potential determined at this time
Egg is 2.5 mm in diameter at end of 1st week
Mitosis, a process of cell division, occurs during this period
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Fetal Development

10. Rejection from the body
A variety of reasons cause about 50% of fertilized eggs to spontaneously abort during this period
Reasons include:
Rejection from the body
Continuance of ingestion of drugs or alcohol by mother (usually unaware of pregnancy at this time)
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Fetal Development

11. Embryonic Period (2nd Week - 2nd Month)
The differentiation of embryonic cells into layers marks the beginning of the embryo, or embryonic period
Period when all body systems form
Highly sensitive for susceptibility of congenital malformations, or abnormal conditions with which an infant is born
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Fetal Development

12. 3 Layers of Cells in the Embryonic Period:
Ectoderm--sense organs and nervous system develop from this layer
Mesoderm--accounts for formation of muscular, skeletal, circulatory systems
Endoderm--eventually accounts for formation of digestive and glandular systems
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Fetal Development

13. Embryonic Period: End of the 1st Month
1/4 inch (6 mm) long
1 oz. Weight
Crescent-shaped with small limb buds on sides
Tail with tiny ridges
Rudimentary circulatory system is forming
Heart begins to beat
Growth acceleration
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Fetal Development

14. Embryonic Period: End of 2nd Month
1.5 inches long
Beginning of face, neck, fingers, toes develop
Limb buds lengthen
Muscles enlarge
Sex organs begin to form
Rapid brain development
Embryo is firmly planted on uterine wall and is receiving nourishment from placenta and umbilical cord
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Fetal Development

15. Early Fetal Period (3rd - 6th Month)
Period of the fetus begins around the 3rd month and continues until delivery
Movement first becomes apparent to mother at this time
No new anatomical features appear during this period, yet still critical time
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Fetal Development

16. Early Fetal Period: 3rd Month
Rapid growth, 3 inches long at end of 3rd month
Sexual differentiation continues
Teeth buds emerge
Stomach and kidneys begin to function
Vocal cords appear
Reflex actions felt: opens/closes mouth, clenches fist, sucks thumb
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Fetal Development

17. Early Fetal Period: 4th Month
Most rapid growth rate (doubles in length to 6-8 inches)
6 oz. Weight
Hands fully shaped
Bony tissue begins to form
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Fetal Development

18. Early Fetal Period: 5th Month
Reaches 1/2 of birth length (8-10 inches)
Only 10% of birth weight (1/2 lb.)
Skin, hair, nails appear
Internal organs grow and assume proper anatomical positions
Pigmented hair on head and eyebrows appears
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Fetal Development

19. Early Fetal Period: 6th Month
13 inches long
1 lb. Weight
Eyelids reopen and are completed
Structurally complete but functionally immature
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Fetal Development

20. Later Fetal Period (7th - 9th Month/Birth)
From the 7th month to birth, the fetus triples in weight
This is a period of filling out
Preparation for birth
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Fetal Development

21. Later Fetal Period: 7th Month
A layer of adipose tissue begins to form under skin (serves as both insulator and food supplier)
Rapid 2-4 lb. Weight gain
14-16 inches long
Fetus is quiet for long periods of time
Brain more active and is increasing control over body systems
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22. Later Fetal Period: 8th Month
Fetus is more active (frequent changes in position)
Fatty deposits distributed
16-18 inches long
4-6 lbs.
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23. Later Fetal Period: 9th Month (Birth)
19-21 inches long
6-8 lbs.
Birth process is initiated by placenta and contraction of uterine muscles
Birth generally occurs after week 40 of gestation (normal is wks.)
Find out more about birth at:
Childbirth.org
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Fetal Development

24. Review Activity
Now it is time to test your new knowledge on Fetal Development!
Click the arrow above to view and print a “Review Activity” worksheet.
The next five slides will show only pictures and brief descriptions of each of the five periods of development in random order.
Your job is to write down the letter of the slide next to the corresponding stage on the worksheet.
We will go over the answers at the end of the lesson. Good luck!
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Fetal Development

25. A. Movement first becomes apparent to the mother
Fetus begins to suck it’s thumb
Skin, hair, and nails appear
No new anatomical features during this period, yet still a critical time
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26. B. The sperm meets and penetrates the ovum, or egg 11/22/2018
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27. C.
The differentiation of embryonic cells into layers marks the beginning of this period
Highly susceptible period for congenital malformations
Heart begins to beat
Beginnings of face, neck, fingers, toes develop
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28. D. Genetic potential determined during this period Mitosis occurs
50% of fertilized eggs spontaneously abort at this time
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29. E. Fetus triples in weight Period of filling out and preparation
Rapid weight gain
More active
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30. Answers: How did you do? 1. Conception B 2. Zygotic Period D
3. Embryonic Period C
4. Early Fetal Period A
5. Later Fetal Period E
Good Job!
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Fetal Development

31. References
Dacey, J.S. & Travers, J.F. (2002) Human Development Across the Lifespan. McGraw Hill. New York
Gallahue, D.L. & Ozmun, J.C. (2002) Understanding Motor Development. McGraw Hill. New York
Fetal Development Overview:
Conception Icon:
Ovum Icon:
Sperm Icon:
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Fetal Development

32. Review Activity 1. Conception 2. Zygotic Period 3. Embryonic Period
4. Early Fetal Period
5. Later Fetal Period
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