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Exploring Lifespan Development

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Exploring Lifespan Development Chapter 2 Prenatal Development (Part 2) Genital differentiation pics * * Quick Quiz: What is the purpose of a menstrual cycle? – PowerPoint PPT presentation

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Title: Exploring Lifespan Development


1
Exploring Lifespan Development
  • Chapter 2
  • Prenatal Development
  • (Part 2)

2
Quick Quiz
  • What is the purpose of a menstrual cycle?
  • T/F Women are born with all the eggs they will
    ever have.
  • Conception happens where in a womans body?
  • T/F A woman is pregnant for 10 months.
  • The most dramatic changes in our development
    occur when?
  • T/F All embryos start out as girls.

3
Prenatal Development is Divided into 3 Periods
  • Period of the Zygote (1-2 weeks) (Germinal stage)
  • Period of the Embryo (3-8 weeks) (Embryonic
    stage)
  • Period of the Fetus (9 weeks to birth)
  • (stages of pregnancy/fetal development are also
    referred to as trimesters, or 2 month increments)

4
1. Period of the Zygote
  • Conception Cells Zygote travels
    Implantation
  • Occurs ? Divide ? to uterus ? into
    uterine wall
  • 0 hours 36 hrs 3-4 days 1 week

5
From Conception to Implantation
6
Internal Female Organs
Uterus
Fallopian Tube
Fallopian Tube
Ovary
Ovary
(Via Laparoscopic Surgery)
7
Know
  • The final step in the period of the zygote is
    Implantation to the uterine wall.
  • Why?

8
Implantation Facts (the answer to Why?)
  • The dividing cell or blastocyst will not develop
    if it is not implanted, for it needs nourishment
    from the mother.
  • Implantation takes about 1 week to complete.
  • Implantation triggers hormonal changes that tell
    the womans body not to menstruate.
  • Once a Zygote is firmly implanted it is now
    called an Embryo.

9
Cell Division Implantation (what it looks
like)
Blastocyst hatching out of the hard outer shell
before it can begin to implant
Implantation! On to the next phase
Blastocyst
10
2. Period of the Embryo
  • The embryos body structures and internal organs
    develop.
  • Leg, arm buds appear, sensory systems and the
    brain and nervous system have begun to develop.
  • The embryo can sense its world, respond to touch
    and is moving. (mom cant feel it yet!)
  • Amniotic fluid cradles the embryo and the
    umbilical cord nourishes it and connects it to
    the mothers blood supply.
  • Growth of the head takes precedence over growth
    of the lower parts of the body

11
Period of the Embryo, cont.
  • The heart begins to beat at 6 weeks of pregnancy.
  • The placenta permits the embryo to exchange
    nutrients with mother
  • Placenta filters oxygen/nutrients which pass from
    mother to embryo and permits carbon dioxide/waste
    products to pass to the mother from the embryo.
  • Mother and embryo have separate circulatory
    systems

12
The Placenta (In Pictures!)
13
Guess What Guys?
  • You all started out as a female during the embryo
    stage of development!
  • At 9 weeks of pregnancy your Y chromosome kicked
    in and here you are, the vagina turned into a
    penis.

14
Which Embie is A Human?
Dolphin
Water Buffalo
Komodo Dragon
Whale
Mouse
Human
15
Embryo Development
  • Weeks
  • 3 through 8

3 ½ wks Neuronal development begins 8 wks
Neurons begin to fire!
6 wks My heart beats!
1 inch long and ½ oz.
16
3. Period of the Fetus
  • The longest prenatal period.
  • Further maturation of fetal organ
    systems/dramatic gains in size.
  • Gender can be determined via ultrasound.
  • Significant increase in brain maturity means new
    behavioral capacities ability to regulate its
    own basic body functions.

17
9-12 Weeks of Fetal Development
  • The brain signals the fetus to kick, curl its
    toes, open its mouth, and suck its thumb.
  • Fingernails, toenails, tooth buds and eyelids
    that open and close are formed.
  • 3 inches, lt 1 oz.

9 weeks
12 weeks
18
13-24 Weeks of Fetal Development
22 wks
16 wks
20 wks
24-25 wks
19
13-24 Weeks of Fetal Development
  • Skin thickens and is covered with Vernix-which
    protects it. A soft downy hair develops called
    Lanugo which helps the vernix stick.
  • Movements are now strong enough for mom to feel.
  • Alternates between periods of sleep/waking.
  • Fingers/toes completely formed
  • Fetus develops a temperament/activity level
  • Fetal hiccoughs common
  • Eyebrows, eyelashes and scalp hair emerge.
  • 12 inches, 1.8 lbs.

20
What is the Age of Viability?
  • The point at which a fetus can survive outside
    the womb.
  • Usually between
  • 23-24 weeks of pregnancy.

22 weeks
21
25-38 Weeks of Fetal Development
  • Fetus practices breathing by breathing and
    swallowing amniotic fluid
  • Heart/lungs capable of sustaining independent
    life.
  • Layer of fat is added to aid in temperature
    regulation
  • Fetus assumes head down position.
  • 19-20 inches, 7.5 lbs.

22
Question
  • True or false
  • Prenatal fetal movement can predict infant
    activity levels after birth.

23
Critical Periods in Prenatal Development
  • There are specific times during prenatal
    development when certain organs are developing
    rapidly.
  • If there is exposure to a Teratogen during these
    Critical Periods there can be harm done to the
    developing embryo/fetus.

24
Critical Periods in Prenatal Development
25
Teratogens
  • Environmental agents that can harm the developing
    embryo or fetus.
  • STDs
  • HIV/AIDS
  • Rubella
  • Toxemia
  • Rh Incompatibility

26
Teratogens, cont.
  • Drugs taken by the parents
  • Heroin/Methadone
  • Marijuana
  • Cocaine
  • Alcohol
  • Cigarettes

27
Teratogens, cont.
  • Environmental hazards
  • Parental age

28
Know
  • The embryo is generally more vulnerable to
    exposure to teratogens than the fetus.
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