Identify and describe the stages and factors that can affect human development from conception through birth REVIEW THE STAGES OF FETAL DEVELOPMENT EXPLORE FACTORS AFFECTING FETAL DEVELOPMENT PROMOTE HEALTHY FETAL DEVELOPMENT EXPLORE CONCEPTION Gain a better understanding of how a fetus develops, and the mother physically changes during pregnancy.

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2. OUTCOMES
after this lesson, students will be able to:
 Identify and describe the stages and factors that can affect human
development from conception through birth
 REVIEW THE STAGES OF FETAL DEVELOPMENT
 EXPLORE FACTORS AFFECTING FETAL DEVELOPMENT
 PROMOTE HEALTHY FETAL DEVELOPMENT
 EXPLORE CONCEPTION
Gain a better understanding of how a fetus develops, and the mother physically
changes during pregnancy.
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3. Conception
 Revise lesson 3 (fertilization)
 Summary:
 Conception occurs when an egg from the mother is fertilized by a sperm from the
father. In humans, the conception process begins with ovulation, when an ovum, or
egg (the largest cell in the human body), which has been stored in one of the
mother's two ovaries, matures and is released into the fallopian tube.
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4. Stages of Prenatal Development
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5. Prenatal Development: GERMINAL STAGE
 Begins at conception when the sperm and egg cell unite in one of the two fallopian tubes.
 The fertilized egg is called a zygote.
 Just a few hours after conception, the single-celled zygote begins making a journey down the fallopian tube to
the uterus.
 Cell division: 24 to 36 hours after conception Through the process of mitosis.
 zygote first divides into two cells, then into four, eight, sixteen, and so on.
 Once the eight-cell point has been reached, the cells begin to differentiate and take on certain characteristics
that will determine the type of cells they will eventually become.
 Cells multiply
 Cell division continues at a rapid rate during the approximately week-long journey from fallopian tube to
uterus wall.
 The cells develop into what is known as a blastocyst. The blastocyst is made up of three layers, each of which
develops into different structures in the body.
 Ectoderm: Skin and nervous system
 Endoderm: Digestive and respiratory systems
 Mesoderm: Muscle and skeletal systems
https://www.verywellmind.com/stages-of-prenatal-development-2795073
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6. Prenatal Development: GERMINAL STAGE
 Finally, the blastocyst arrives at the uterus and attaches to the uterine wall (IMPLANTATION)
 Implantation occurs when the cells nestle into the uterine lining and rupture tiny blood
vessels.
 The connective web of blood vessels and membranes that form between them will provide
nourishment for the developing being for the next nine months.
 Implantation is not always an automatic and sure-fire process.
 Researchers estimate that approximately 60% of all natural conceptions never become properly
implanted in the uterus, which results in the new life ending before the mother is ever aware she is
pregnant.
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7. Summary………….
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8. Prenatal Development: Embryonic Stage
 At this point, the mass of cells is now known as an embryo.
 The beginning of the third week after conception marks the start of the embryonic period, a
time when the mass of cells becomes distinct as a human.
 The embryonic stage plays an important role in the development of the brain.
 Approximately four weeks after conception, the neural tube forms.
 This tube will later develop into the central nervous system including the spinal cord and
brain.
 The neural tube begins to form along with an area known as the neural plate.
 The earliest signs of development of the neural tube are the emergence of two ridges that
form along each side of the neural plate.
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9. Prenatal Development: Embryonic Stage
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11. Prenatal Development: Embryonic Stage
 By the eighth week of development, the embryo has all of the basic organs and parts except
those of the sex organs.
 At this point, the embryo weighs just one gram and is about one inch in length.
 By the end of the embryonic period, the basic structures of the brain and central nervous
system have been established.
 At this point, the basic structure of the peripheral nervous system is also defined.
 The production of neurons, or brain cells, begins around day 42 after conception and is
mostly complete sometime around the middle of pregnancy.
 As neurons form, they migrate to different areas of the brain. Once they have reached the
correct location, they begin to form connections with other neural cells, establishing
rudimentary neural networks.
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13. Prenatal Development: Fetal Stage
 Once cell differentiation is mostly complete, the embryo enters the next stage and becomes
known as a fetus.
 This period of development begins during the ninth week and lasts until birth.
 The early body systems and structures established in the embryonic stage continue to
develop.
 The neural tube develops into the brain and spinal cord and neurons continue to form.
 Once these neurons have formed, they begin to migrate to their correct locations.
 Between the ninth and twelfth week of gestation (at the earliest), reflexes begin to emerge.
 The fetus begins to make reflexive motions with its arms and legs.4
 During the third month of gestation, the sex organs begin to differentiate.
 By the end of the month, all parts of the body will be formed.
 The end of the third month also marks the end of the first trimester of pregnancy.
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14. Prenatal Development: Fetal Stage
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15. The
fetal
stage
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16. Three Stages of Prenatal Development
 - When does Psychological Development start?
 WHAT IS YOUR OPINION ON WHTEHETHER THE GERMINAL STAGE TRULY IS THE
FIRST STAGE OF DEVELOPMENT?
 - VIDEO (‘NICE TO KNOW’ )- YOU HAVE COVERED THIS IN PSYCH 2ND YEAR
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17. Month by month development:
MONTH 1 – WEEK 1-4
 After an egg has been fertilized and implants into the uterine lining, a sac
grows around it. This becomes the amniotic sac and will hold the amniotic
fluid and cushion the embryo. The placenta also forms during this month. This
will bring nutrition and support to the baby from the mother.
 The face and eyes begin to develop, and the heart begins to beat. By the end
of the 4th week, your baby will slightly smaller than a grain of rice! B
vitamins play a crucial role in you and your baby’s development and your
health during pregnancy. Vitamin B6 and Folic Acid (Vitamin B9) are especially
important for early development, so make sure you are getting the right
amounts of these.
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18. Month by month development:
Month 3 – Week 10-14
 The limbs, as well as the hands, feet, fingers, and toes, become well
developed. The fingernails and toenails begin to form. The external ears and
teeth begin their development as well. Though reproductive organs haven
begun to form, they can’t yet be determined on an ultrasound or sonogram.
By the end of the 3rd month, your baby is fully formed (with all organs and
extremities present), he or she weighs about an ounce and is 4 inches long!
 After the 3rd month of development, the chance of miscarriage drops
considerably.
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19. Month by month development:
Month 4 – Week 15-19
 Hair, eyelids, eyelashes, and nails become well developed. The heartbeat is
now clearly audible through a Doppler instrument. The teeth become denser,
and the baby begins to stretch, yawn and make other movements. The
reproductive organs are now visible on an ultrasound. Your baby can now
stretch, suck their thumb, yawn, and make super cute faces.
 This is the month that his or her nervous system develops. Their reproductive
system also fully develops meaning your doctor can tell you whether you are
having a girl or boy via ultrasound. By the end of the 4th month, your baby is
about 6 inches long and weighs 4 ounces!
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20. Month by month development:
Month 5 – Week 20-24
 This month you may start to feel the baby move. Hair growth continues on
the baby’s head and body. The shoulders and back become covered with a
thin hair called lanugo. A thick substance, called vernix caseosa, covers the
skin to keep it protected from the exposure to amniotic fluid. This layer will
shed before the baby is born. At the end of month 5, your baby is about 10
inches long and can weigh anywhere from .5 lbs – 1 lb!
 If your baby is born prematurely after the 23rd week, he or she will be kept in
the NICU for a better chance of survival.
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21. Month by month development:
Month 6 – Week 25-30
 The skin is still translucent yet reddish and wrinkled. His or her fingerprints
and toe prints become well developed. The baby’s eyelids become parted,
and the eyes can be opened. Your baby will respond to external stimuli such
as sounds by increasing their pulse or moving. This is when you may
experience your baby’s hiccups in jerk-like motions. At the end of month 6,
your baby is about 12 inches long and can weigh close to 2 lbs!
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22. Month by month development:
Month 7 – Week 26-29
 During this month, your baby will continue to grow and develop the existing
organs and systems. In addition, a layer of fat will begin to be stored. At this
stage, hearing is fully developed. He or she will react to sound, pain, and
light and often changes position. The amount of amniotic fluid that cushions
the baby begins to decrease as the baby grows larger. At the end of this
month, your baby is about 14 inches long and can weigh between 2 – 4 lbs!
 If born prematurely after week 27, your baby has a better chance of survival.
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23. Month by month development:
Month 8 – Week 30-34
 The baby continues to mature during this month, adding to fat stores and
experiencing a rapid development of the brain. The baby can see at this stage
and will begin to kick more. Most of the internal organs and systems are fully
developed, but the lungs still need time to mature. By month 8, your baby is
close to 18 inches long and can weigh close to 5 lbs!
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25. Month by month development:
Month 9 – Week 35-40+
 The lungs become mature during this time in preparation for birth. Reflexes
become more coordinated, allowing the baby to respond to sounds, blink, grasp,
and turn his or her head. The baby may move less during the last few weeks and
will move into a position for birth, with the head down near the birth canal. Your
baby is now about 18-20 inches long and can weigh at least 7 lbs!
 Video- Fetal development month by month
 Birth control pills?
 Self assessment questions: https://www.proprofs.com/quiz-
school/story.php?title=fetal-development-quiz
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26. Reference list
 https://www.verywellmind.com/stages-of-prenatal-development-2795073
 https://www.whattoexpect.com/getting-pregnant/ovulation/implantation/
 https://www.researchgate.net/figure/Normal-and-abnormal-neural-tube-
formation-A-Major-steps-of-neural-tube-formation-The_fig1_336266755
 https://www.babycenter.com/pregnancy/your-baby/fetal-development-
week-by-week_10406730
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