Conception and Fetal Development

1
Conception and Fetal Development

• Chapter 4

2
Conception

• Components of fertility
• Male and female
• Menstrual Cycle
• Hormonal
• Ovarian
• Endometrial

3
Hormonal Function

• Function of hormones
• FSH
• LH
• Progesterone
• Testosterone

4
Cellular Division

• Mitosis cellular division for healing
• Meiosis cellular division r/t reproduction
• Oogenesis
• Spermatogenesis

5
Fertilization

• Viability of ova vs. sperm
• Fertilization occurs in distal 1/3 of tube
• Embryonic development occurs immediately
• HCG stimulates corpus luteum to secrete
  progesterone

6
Implantation

• Occurs 7 days after fertilization
• Implants near fundus
• Chorionic villae implant into endometrium which
  becomes decidua
• Placental formation begins
• Outer layer of chorionic villae become membranes-
  chorion and amnion

7
Placenta

• Structure cotyledons, circulation
• Functions
• Fetal respiration, nutrition, excretion
• Transport of passive immunity (IGG)
• Stores glycogen and iron
• Produces HCG, progesterone, estrogen, HPL
• Suppresses maternal immune response

8
Umbilical Cord and Amniotic Fluid

• Umbilical Cord
• One vein-two arteries
• Whartons jelly
• Amniotic fluid
• Volume changes
• Diagnostic
• Alkaline

9
Fetal Circulation

• Maternal blood carries oxygen disposes of waste
• Fetal Hgb greater affinity for 02
• Vein transports 02
• Purpose of foramen ovale and ductus is to bypass
  non-functional fetal organs

10
Human Development

• Pre-embryonic-first 21 days
• Embryonic-21days-9 wks
• Most susceptible to teratogens
• Period of differentiation
• Fetal 9-40 weeks
• Period of continued development

11
What parents want to know?

• 4-12 wks- All body parts formed, heart beating
• 16 wks- Sex can be determined
• 20 wks- Lanugo, vernix, hair, movement, favorite
  position, sleep-awake pattern, suck, grasp
• 24 wks- Respiratory movements

12
Development Milestones

• 28 wks- eyes open, breathe, surfactant
  developing, 2/3 of birth weight
• 32 wks- active period, gaining weight
• 35-36 wks- surfactant will prevent alveoli
  collapse
• 38-40 wks- passive immunity (IGG) received from
  mom