Chapter 6

Conception

and Fetal Development

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Cell division

Mitosis

Meiosis

Gametogenesis

Spermatogenesis

Oogenesis

Conception

Ovum

Sperm

Conception

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Fertilization

Morula

Blastocyst

Implantation

Chorionic villi

Decidua basalis

Conception (Cont.)

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Primary germ layers

Ectoderm

Mesoderm

Endoderm

Development of the embryo

Membranes

Chorion

Amnion and amniotic cavity

Embryo and Fetus

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Amniotic fluid

Serves numerous functions

Volume is important to fetal well-being

Yolk sac

Becomes primitive digestive system

Umbilical cord

Supplies the embryo with maternal nutrients and

oxygen

Embryo and Fetus (Cont.)

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Placenta

Structure

• Maternal-placental-embryonic circulation by day 17

Function

• Endocrine gland

• Metabolic function and waste

• Nutrient storage

Embryo and Fetus (Cont.)

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Fetal maturation

Viability

• Capability of fetus to survive outside uterus

• Limitations based on central nervous system function and

oxygenation capability of lungs

Fetal circulatory system

• FHR 110 to 160 beats/min

Embryo and Fetus (Cont.)

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Fetal maturation

Hematopoietic system

Respiratory system

• Primary surfactants

Gastrointestinal system

Hepatic system

Renal system

Embryo and Fetus (Cont.)

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Fetal maturation

Neurologic system

• Sensory awareness

Endocrine system

Reproductive system

Musculoskeletal system

Integumentary system

Immunologic system

Embryo and Fetus (Cont.)

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Multifetal pregnancy

Twins

• Dizygotic twins

• Monozygotic twins

• Conjoined twins

Other multifetal pregnancies

Embryo and Fetus (Cont.)

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Teratogens

Drugs

Chemicals

Infection

Exposure to radiation

Maternal conditions

Maternal nutrition

Malnutrition

Nongenetic Factors

Influencing Development

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A woman is 8 months pregnant. She tells the nurse that

she knows her baby listens to her but her husband thinks

she is imagining things. The most appropriate response

by the nurse is:

“Many women imagine what their baby is like.”

“Babies in utero do respond to their mother’s voice.”

“You’ll need to ask the doctor if the baby can hear yet.”

“Thinking that your baby hears will help you bond with

the baby.”

Question

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