Essentials of Anatomy and Physiology

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CHAPTER 21

Chapter Outline

Human Development
Fertilization
Implantation
Embryo and Embryonic Membranes
Placenta and Umbilical Cord
Placental hormones
Parturition and Labor
The Infant at Birth
Genetics
Chromosomes and Genes
Genotype and Phenotype
Inheritance: Dominant–Recessive
Inheritance: Multiple Alleles
Inheritance: Sex-Linked Traits

BOX21–1 TWINS

BOX21–2 FETAL DIAGNOSIS

BOX21–3 CONGENITAL FETAL INFECTIONS

BOX21–4 FETAL ALCOHOL SYNDROME

BOX21–5 PREMATURE BIRTH

BOX21–6 APGAR SCORE

BOX21–7 SOLUTION TO GENETICS QUESTION

Student Objectives

• Describe the process of fertilization and cleavage
  to the blastocyst stage.


• Explain when, where, and how implantation of the
  embryo occurs.


• Describe the functions of the embryonic mem-
  branes.


• Describe the structure and functions of the pla-
  centa and umbilical cord.


• Name and explain the functions of the placental
  hormones.


• State the length of the average gestation period,
  and describe the stages of labor.


• Describe the major changes in the infant at birth.


• Describe some important maternal changes during
  pregnancy.


• Explain homologous chromosomes, autosomes,
  sex chromosomes, and genes.


• Define alleles, genotype, phenotype, homozygous,
  and heterozygous.


• Explain the following patterns of inheritance:
  dominant–recessive, multiple alleles, and sex-
  linked traits.