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Prenatal

August 13, 2012 by  

prenatal exam

The human nest.

Prenatal development is both complicated and fast paced. In only 40 weeks, a single fertilized egg matures into a baby. We explore the question: when does life begin?

Here’s what is included in this lesson:

  • Ovulation
  • Fertilization
  • Implantation
  • Germinal stage
  • Embryonic stage
  • Fetal stage

Read chapter 3 of Berk’s Development Thru The Lifespan

Here are the resources you need:

CLUSTER

SLIDES

TERMS

[dropdown_box expand_text=” Terms To Know” show_more=”More” show_less=”Less” start=”hide”]

  • 300 bones
  • 70+ reflexes
  • age of viability = somewhere about 6 months pregnant, fetus can survive if born
  • alcohol-related neurodevelopmental disorder (ARND) = alcohol-related developmental disabilities
  • amnion = fluid-filled sac that holds developing fetus
  • anoxia = low oxygen; potential cause of brain damage during delivery
  • Apgar Scale = evaluation of newborns on complexion, pulse, reflexes, activity & respiration
  • blastocyst
  • blastula
  • breech position = non-head-first birth (buttocks or feet)
  • cancer
  • cervix
  • cesarean delivery = surgical delivery of babies through abdominal wall, typically in distress
  • chorion = outermost layer of an embryo, developed by follicle cells of ovary
  • chromosomes
  • cilia
  • cleavage
  • corpus luteum
  • DNA
  • egg
  • ejaculatation
  • embryo = first 8 weeks of prenatal development
  • embryo stage
  • enzymes
  • expected date of delivery
  • expel
  • fallopian tube
  • fallopian tube contractions
  • female sex cells
  • fertilization
  • fertilized egg
  • fetal alcohol spectrum disorder (FASD) = continuum of disorders cause by prenatal alcohol exposure
  • fetal alcohol syndrome (FAS) = prenatal exposure to alcohol, leading cause of mental retardation
  • fetal monitors = monitors fetal heart rate & mother’s uterine contractions
  • fetal stage
  • fetus = from week 8-40 of prenatal development
  • fimbria
  • follicle
  • fraternal twins
  • FSH (folicle stimulating)
  • full term
  • germinal stage
  • hCG (human chorionic gonadotrophin)
  • hormones
  • human placental lactogen (HPL)
  • implantation
  • infant mortality = death of infant under 1 year old
  • inflammation
  • irregular ovulation
  • lanugo = soft fine hair on fetus, normally disappears before birth
  • last menses period (LMP)
  • LH (luteinizing hormone)
  • ligaments
  • menstrual period
  • morula
  • natural childbirth (prepared) = 1930’s movement, noninvasive methods to reduce delivery pain
  • Neonatal Behavioral Assessment Scale (NBAS) = test for infant 3 days to 4 weeks, checklist
  • neural tube = develops into spinal cord and brain
  • non-rapid-eye-movement (NREM) sleep = 3 sleep stages that precede REM
  • ova (plural)
  • ovarian stem cells
  • ovaries
  • ovulation
  • ovum
  • partial fetal alcohol syndrome (p-FAS) = prenatal alcohol exposure: CNS damage & growth deficiency
  • placenta = organ that filters mother’s blood supply for developing fetus
  • preterm infants
  • progesterone
  • rapid-eye-movement (REM) sleep = stage of sleep that includes vivid dreams & sleep paralysis
  • reflex = smallest amount of behavior, sensory neuron goes to spinal cord & triggers motor neuron
  • Rh factor incompatibility = can be a problem in delivery with fetus & mother’s blood come in contact
  • scar tissue & cysts
  • small-for-date infants = below 10th percentile in weight
  • sperm
  • sperm head
  • sperm middle
  • sperm tail
  • states of arousal = levels of consciousness, including sleep
  • sudden infant death syndrome (SIDS) = unexpected death of infant under age 1
  • surfactant
  • teratogen = any substance that interferes with embryo development
  • testicles
  • trimesters = 40 weeks of pregnancy divided into 3 sections
  • trophoblast
  • tubal ectopic pregnancy
  • umbilical cord = connects fetus and placenta
  • unfertilized egg
  • uterine contractions
  • uterus
  • vagina
  • vernix = vernix caseosa, white coating on newborn’s skin, waxy texture
  • viability
  • visual acuity = clearness, focus; newborn have limited vision
  • XX
  • XY
  • zygote

 

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NOTES

[dropdown_box expand_text=” For You” show_more=”Notes” show_less=”Less” start=”hide”]

  • Female sex cells
    • Eggs & Ovaries
    • Left & right
    • Attached to uterus by ligaments
      • Not attached to fallopian tubes
    • 250k cells in each at birth
      • Limited supply
      • Ovarian stem cells add more
  • Classic Example
    • Hormones stimulate monthly
      • FSH (folicle stimulating)
      • LH (luteinizing hormone)
    • One ovary ovulates
      • Randomly left or right
    • Release one egg
    • Follicle swells with fluid
    • Follicle erupts
    • Mature egg pushed thru wall
      • Fluid & cell
    • Fallopian tube fimbria (fringe)
      • Fill with blood
      • Brushes egg into tube
    • Fallopian tube contractions move egg along toward uterus
    • If unfertilized, egg moves to uterus, expelled
    • If fertilized, egg moves to uterus
      • Subdividing as it goes
      • Implanted
  • In real life
    • Can release more than one egg
      • Fraternal twins
      • Each can have its own Dad
    • Ovulate with no menstrual period
      • Can ovulate but no egg
    • Irregular ovulation
    • Normal cycle varies between folk
      • 21-35 days typical
    • Normal cycle can vary in you
    • Pain when ovulation begins
    • Pain when egg pushed out
    • Pain from fallopian contractions
    • Pain from uterine contractions
  • Ovum (ova is plural)
    • Grain of sand
    • 23 chromosomes
    • 22 match 22 of men
    • 23rd is X chromosome
  • Male sex cells
    • Testicles
    • Outside ovaries
    • Sperm factories
  • Sperm
    • Produced daily
    • Kept alive by nurse cells
    • Takes 2-3 months to mature
    • Stored for release
    • Die daily
    • 23 chromosomes
      • 22 match the 22 of women
      • 23rd determines sex
        • X or Y
        • Girl (XX) or boy (XY)
    • 3 parts
      • Head; covered with enzymes
      • Middle (connector)
      • Tail
  • Process
    • Sperm ejaculate 300 million
    • Enter vagina
    • 20% die immediately
    • Can live 4-5 days
    • 10% make it through cervix; 3 million
    • Must swim upstream
    • Go to correct fallopian tube
  • Fallopian tubes
    • About width of pencil
    • Collect & transport zygote
    • Go from ovary to uterus
    • Long, thin tubes
    • 2 (left & right)
  • Fimbria = fringe
    • collection end of tube
    • finger-like projections
    • actively go and get egg
  • Cilia = tiny hair-like fibers
    • “feed” it into fallopian tube
  • Problems:
    • tubal ectopic pregnancies
    • inflammation (infection)
    • cancer (extremely rare)
    • scar tissue (adhesions)
    • cysts
    • fertilization occurs in fallopian tube
  • Classic Example
    • Good swimmers
    • 1000 reach ovum
    • 1 binds with egg
    • Penetrates egg
    • Swells in size
    • Releases DNA
    • Chromosomes line up
    • Pairs connect
    • Dominant-recessive
    • Unique combinations
    • Takes 24 hours
  • Germinal Stage Week 1 & 2
    • Week 1
    • Fertilization to implantation
    • Zygote = 1 fertilized egg
      • Surrounded by plasma membrane
      • Mother’s body changes
      • Uterine lining is developing
    • Cleavage
      • partitions zygote into 2 cells
      • 30 hours after fertilization
    • Zygote remains the same size
      • Component cells are smaller
    • Morula
      • Solid ball of 32 cells
      • Day 4-5 but still same size
    • Blastula
      • Same size as original cell
      • Hollow ball of 250+ cells
      • Filled with fluid
      • 2 layers
        • Inner layer = blastocyst
          • becomes embryo
        • Outer layer = trophoblast
          • attaches itself to uterine wall = implantation
    • Implantation
      • Blastula arrives at uterus
  • Day 7-8
    • Stays in uterus a couple of days
    • Imbeds itself in uterine wall
  • Day 11-14
    • Blastula secretes hormones
    • hCG (human chorionic gonadotrophin)
    • Maintains corpus luteum
    • Corpus luteum secretes progesterone for 1st trimester
      • human placental lactogen (HPL)
    • Anti-insulin properties
    • Facilitates fetus’ energy supply
    • Mother may notice missed period
    • Conception = fertilization or implantation?
  • Embryo Stage Week 3-8
  • Fetal Stage Week 9-39
    • Week 24 (6 months)
      • 50% viability
      • Lungs produce surfactant
      • Surfactant
        • keeps lungs air sacs from collapsing when we exhale
    • Week 26-27 (3rd trimester)
      • 85% viability
      • 1.5-2 pounds, 10 inches
    • Week 28 (7 months)
      • Brain surface is wrinkled
      • Breathing & body temp controlled by brain
    • Week 32 (8 months
      • Eyes open when alert
      • Closed when sleeping
      • Eye color is blue
        • regardless of permanent color
        • requires exposure to light
    • Week 39-40
      • 98% viability
      • Expected date of delivery
      • 280 days from last menses period (LMP)
      • 8 pounds, 20 inches
    • Week 40-42
      • full term
      • 70+ reflexes
      • has 300 bones
      • adults have 206 (some fuse together)

 

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 QUIZ

[dropdown_box expand_text=” For You” show_more=”Quiz” show_less=”Less” start=”hide”]

  • 1. Which weeks are the fetal stage of development:
    • a.           1-4
    • b.           3-11
    • c.           9-40
    • d.           10-49
  • 2. A solid ball of 32 cells is called a:
    • a.           ovumento
    • b.           morula
    • c.           zygote
    • d.           cilia
  • 3. When is a fetus 50% viable?
    • a.           week 18
    • b.           week 24
    • c.           week 28
    • d.           week 32
  • 4. If 300 million sperm enter the vagina, how many reach the ovum?
    • a.           1
    • b.           ~1000
      c.           ~10,000
    • d.           ~100,000
  • 5. Typically, fertilization occurs in the:
    • a.           fallopian tube
    • b.           vagina
    • c.           uterus
    • d.           cervix

For the answers: Click Here

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DISCUSSION ITEM

  • What types of birth control are acceptable to you?

 

 

 

 

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