Experiencing The Lifespan JANET BELSKY Experiencing The Lifespan 3rd edition Chapter 2: Prenatal Development, Pregnancy, and Birth Copyright © 2013, 2011 by Worth Publishers

Figure 2.1 The female and male reproductive systems JANET BELSKY Copyright © 2013, 2011 by Worth Publishers

Figure 2.2 The human building blocks: The nucleus of every human cell contains chromosomes, each of which is made up of two strands of DNA connected in a double helix. JANET BELSKY Copyright © 2013, 2011 by Worth Publishers

Figure 2.3 A map of human chromosomes: This magnified grid, called a karyotype, shows the 46 chromosomes in their matched pairs. The final pair, with its X and Y, shows that this person is a male. Also, notice the huge size of the X chromosome compared to the Y. JANET BELSKY Copyright © 2013, 2011 by Worth Publishers

Figure 2.4 The events of the germinal stage: The fertilized ovum divides on its trip to the uterus, then becomes a hollow ball called a blastocyst, and finally fully implants in the wall of the uterus at about 14 days after fertilization. JANET BELSKY Copyright © 2013, 2011 by Worth Publishers

Figure 2.5 The neural tube: This structure is one of the first to form after implantation. The brain and spinal cord will develop from it. JANET BELSKY Copyright © 2013, 2011 by Worth Publishers

Figure 2.6 Forming a brain: climbing neurons: During the earlier part of the fetal period, the neurons destined to make up the brain ascend these ladder-like filaments to reach the uppermost part of what had been the neural tube. JANET BELSKY Copyright © 2013, 2011 by Worth Publishers

Figure 2.7 The expanding brain: The brain grows dramatically month by month during the fetal period. During the final months, it develops its characteristic folds. JANET BELSKY Copyright © 2013, 2011 by Worth Publishers

Figure 2.8 Poised to be born: This diagram shows the fetus inside the woman’s uterus late in pregnancy. Notice the placenta, amniotic sac, and umbilical cord. JANET BELSKY Copyright © 2013, 2011 by Worth Publishers

Table 2.1 Measuring Stress in Mothers-to-Be: A Short Section Summary Questionnaire JANET BELSKY Copyright © 2013, 2011 by Worth Publishers

Table 2.2 Examples of Known Teratogens and the Damage They Can Do JANET BELSKY Copyright © 2013, 2011 by Worth Publishers

Table 2.3 Some Examples of Dominant, Recessive, and Sex-Linked Single-Gene Disorders JANET BELSKY Copyright © 2013, 2011 by Worth Publishers

Figure 2.9 Some possible missteps on the path to reproduction: In this diagram, you can see some problems that may cause infertility in women. You can also use it to review the ovulation-to-implantation sequence. JANET BELSKY Copyright © 2013, 2011 by Worth Publishers

Figure 2.10 Labor and childbirth: In the first stage of labor, the cervix dilates; then in the second stage, the baby’s head emerges and the baby is born. JANET BELSKY Copyright © 2013, 2011 by Worth Publishers

Table 2.4 The Major Players and Interventions in Labor and Birth JANET BELSKY Copyright © 2013, 2011 by Worth Publishers