OB Final Study Guide

Chapter 3 Genetics, Conception, Fetal Development, and Reproductive Technology o  30,000 genes in the human genome (organism’s complete set of DNA)  46 chromosomes; 22 homologous pairs of chromosomes and one pair of sex chromosomes  recessive genetic disorders  sickle cell anemia, cystic fibrosis, thalassemia, Tay-Sachs disease  carrier testing  identify individuals who carry one copy of a gene mutation that, when present in two copies causes a genetic disorder; used when there is a family history of genetic disorder  preimplantation testing/preimplantation genetic diagnosis  used to detect genetic changes in embryos that are created using assisted reproductive techniques  prenatal testing  early detection of genetic disorders  risks for conceiving child with genetic disorder  maternal age older than 35, man/woman who has genetic disorder; family history of genetic disorder, history of previous pregnancy resulting in a genetic disorder or newborn  sickle cell anemia o most common of African ancestry o sickle-cell hemoglobin forms rigid crystals that distort and disrupt RBCs; oxygen-carrying capacity of blood is diminished  cystic fibrosis o most common genetic disease of European ancestry o production of thick mucus clogs in bronchial tree and pancreatic ducts o most severe effects are chronic respiratory infections and pulmonary failure  Tay-Sach disease o Most common among Jewish ancestry o Degeneration of neurons and nervous system results in death by the 2 years old  PKU o Lack of enzyme to metabolize the amino acid phenylalanine  leads to severe mental and physical retardation  Huntington’s Disease o Uncontrollable muscle contractions between 30-50 years followed by memory loss and personality o No treatment that can delay mental deterioration  Hemophilia (X-linked) o Lack of factor 8 o Can be controlled with factor 8 from donated blood  Duchenne’s Musclular Dystrophy o Replacement of muscle by adipose or scare tissue with progressive loss of muscle function; often fatal before age 20 due to involvement of cardiac muscle  teratogens  any drugs, viruses, infections, or other exposures that can cause embryonic/fetal developmental abnormality  degree or types of malformation vary on length of exposure, amount of exposure, and when it occurs during human development  exposure after 13 weeks may cause fetal growth restriction or reduction of organ size  toxoplasma is a protozoan parasite found in cat feces and uncooked/rare beef and lamb o can cause fetal demise, mental retardation, blindness when fetus is exposed  rubella  increased risk for heart defects, deafness and/or blindness, mental retardation, fetal demise  cytomegalovirus  increased risk for hydrocephaly, microcephaly, cerebral calcification, mental retardation, hearing loss  herpes varicella/chicken pox  increased risk for hypoplasia of hands and feet, blindness/cataracts, mental retardation  syphilis  increased risk for skin, bone and/or teeth defects, fetal demise  cocaine  increased risk for heart, limbs, face, GI/GU tract defects, cerebral infarctions, placental abnormalities