1. Chapter 23 Pregnancy, Growth, and Development
Pregnancy is the presence of a developing offspring in the uterus
Growth is an increase in size. Involves increases in cell numbers and cell sizes
Development is the continuous process by which an individual changes from one life phase to another
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2. Fertilization
Paths of the egg and sperm cells through the female reproductive tract
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3. Steps in Fertilization
acrosome releases enzymes
sperm cell penetrates zona pellucida
sperm cell’s membrane fuses with egg cell’s membrane
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4. Formation of Morula
zygote
blastomeres
morula
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5. Early Human Development
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6. Implantation
trophoblast will help form the placenta
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7. Summary of Stages and Events of Early Human Prenatal Development
fertilized ovum
zygote forms
cleavage
mitosis increases cell number
morula
solid ball of cell
blastocyst
trophoblast and inner cell mass form
gastrula
primary germ layers form
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8. Hormonal Changes During Pregnancy
Mechanism that preserves uterine lining during early pregnancy
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9. Hormonal Changes During Pregnancy
Relative concentrations of three hormones in maternal blood during pregnancy
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10. Hormonal Changes During Pregnancy
secretion of maintains corpus luteum
corpus luteum secretes estrogens and progesterone
estrogens and progesterone stimulate and maintain uterine lining, inhibit FSH and LH, inhibit uterine contractions, and enlarge reproductive organs
placental lactogen
aldosterone promotes sodium retention
PTH
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11. Derivatives of Each Primary Germ Layer
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12. Embryos three weeks; dorsal view three and a half weeks; lateral view
four weeks; lateral view
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13. Embryonic Development
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14. Changes During Embryonic Development
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15. Placenta
Consists of an embryonic portion and a maternal portion
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16. Placenta at Seventh Week
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17. Embryo at Eight Weeks End of eighth week marks end of embryonic period
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18. Teratogens
structures in developing embryo are sensitive to teratogens at different times
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19. Development
body portions change considerably
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20. Development of External Reproductive Organs
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21. Position of Full-Term Fetus
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22. Major Events of Fetal Development
9th –12th week
ossification centers appear
sex organs differentiate
fetal limbs begin to move
13th – 16th week
body grows rapidly
ossification continues
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23. Major Events of Fetal Development
17th – 20th week
muscle movements stronger
21st – 38th week
body gains weight
subcutaneous fat deposited
eyebrows and eyelashes appear
eyelids open
testes descend
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24. Fetal Circulation
oxygen and nutrients diffuse into the fetal blood from the maternal blood
waste diffuses into the maternal blood from the fetal blood
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25. Fetal Cardiovascular Adaptations
fetal blood has greater oxygen-carrying capacity
umbilical vein-
ductus venosus –
foramen ovale –
ductus arteriosis
umbilical arteries carry blood from internal iliac arteries to placenta
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26. Fetal Circulation
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27. Fetal Circulation Summary
Prenatal Heart
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28. Factors Contributing to the Labor Process
as birth approaches, progesterone levels decrease
prostaglandins synthesized which may initiate labor
fetal head stretches uterus
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29. Birth Process A positive feedback mechanism propels the birth process
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30. Stages in Birth
stage
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31. Milk Production
placental estrogens and progesterone stimulate further breast development
estrogens cause ductile system to grow
progesterone causes alveolar glands to develop
placental lactogen also produces changes in breast
prolactin is released about the 5th week of pregnancy
breast production does not begin until after birth
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32. Postnatal Period Neonatal period
newborn begins to carry on respiration, obtain nutrients, digest nutrients, excrete wastes, regulate body temperature, and make cardiovascular adjustments
Infancy
teeth begin to erupt
muscular and nervous systems mature
communication begins
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33. Major Changes in the Newborn’s Cardiovascular System
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34. Causes of Death
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35. Clinical Application Preimplantation Genetic Diagnosis
Probes disease-causing genes in an eight-celled embryo
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