The human body contains 100 trillion cells There

The human body contains 100 trillion cells. There is a nucleus inside each human cell (except red blood cells). Each nucleus contains 46 chromosomes, arranged in 23 pairs. One chromosome of every pair is from each parent. The chromosomes are filled with tightly coiled strands of DNA. Genes are segments of DNA that contain instructions to make proteins— the building blocks of life.

Gametes and Zygote Sperm Ovum Gametes (reproductive cells) Fertilization Zygote

The Process of Meiosis for Sperm Cells Cell with 46 chromosomes (only one pair of homologous chromosomes is shown here). Each member of the pair has begun to replicate similar to mitotic cell division. First meiotic cell division begins, but does not proceed as in mitosis. Instead of the replicated chromosome splitting apart, one member of each homologous pair becomes a part of the first-generation daughter cell. The second meiotic division proceeds after the first is completed; now the replicated chromosome acquired in the first-generation daughter cell splits apart. Each of the four gametes produced by the two-step process now has acquired one member of the pair of homologous chromosomes.

The Process of Mitosis Cell nucleus with a pair of chromosomes Chromosomes split and replicate to produce two identical pairs The pairs separate, and the cell divides Each daughter cell now has a pair of chromosomes that is identical to the original pair

GENOTYPE AND PHENOTYPE · GENOTYPE: Set of genetic traits a person inherits; a person’s inborn capacity or potential · PHENOTYPE: Set of traits a person actually displays, resulting from a combination of the person’s genotype (potential) and life experiences that modify that potential

Inheritance of Hemophilia, a Sex-Linked Disorder Carrier Mother X X X Normal Father Y XX Normal Daughter (25%) XX Carrier Daughter (25%) XY Normal Son (25%) XY Hemophilic Son (25%)

FREQUENCY OF DOWN SYNDROME (PER 1000) Relationship Between Maternal Age and the Incidence of Down Syndrome 100 90 80 70 60 50 40 30 20 10 0 15 20 25 30 35 40 MATERNAL AGE (YEARS) 45 50

Inheritance of a Dominant Gene Disorder Affected Parent (Has the Disorder) Normal Father D r r Dr Affected (25%) rr normal (25%) (50%)

Inheritance of a Recessive Gene Disorder Carrier Mother D D r Dr Affected (25%) rr normal (25%) Carrier Father r

Risk of Selected Genetic Disorders Chromosomal Down Syndrome Klinefelter syndrome (XXY) Fragile X syndrome Turner syndrome (XO) Dominant Gene Polydactyly Achondroplasia Huntington disease Recessive Gene Cystic fibrosis Sickle-cell disease Tay-Sachs disease 1/800 men 1/1, 200 male births 1/2, 000 female births 1/3, 00 women 1/300 - 1/100 1/2, 300 1/15, 000 - 1/5, 000 1/2, 500 white persons (risk of being a carrier is 1/25) 1/625 African Americans (risk of being a carrier is 1/10) 1/3, 600 Eastern European Jews(risk of being a carrier is 1/300) X Linked Hemophilia 1/2, 500 male babies Multifactorial Congenital heart disease Neural tube defect Cleft lip/cleft palate 1/125 1 - 2/1, 000 1/1, 000 - 1/5, 000 Sources: ACOG (1990); Blatt (1988); Diamond (1989(; Hagerman (1996); Selekman (1993); Stratford (1994).

Who Should Seek Prenatal Counseling? 1. Couples who already have a child with some serious defect such as Down syndrome, spina bifida, congenital heart disease, limb malformation, or mental retardation 2. Couples with a family history of a genetic disease or mental retardation 3. Couples who are blood relatives (first or second cousins) 4. African Americans, Ashkenzzi Jews, Italians, Greeks, and other high-risk ethnic groups 5. Women who have had a serious infection early in pregnancy (rubella or toxoplasmosis) or who have been infected with HIV 6. Women who have taken potentially harmful medications early in pregnancy or habitually use drugs or alcohol 7. Women who have had X rays taken early in pregnancy 8. Women who have experienced two or more of the following: stillbirth, death of a newborn baby, miscarriage 9. Any woman thirty-five years or older Source: Adapted from Fienbloom & Forman (1987) p. 129

The Concept of Range of Reaction for Intellectual Performance child A child B child C Reaction Range Intellectual Performance (IQ) High Average Low Restricted Average Type of Environment Enriched

Measuring the effects of Nature and Nurture: Twin and Adoption Studies

Correlations of IQ Scores Correlation of IQ scores +1. 00 +0. 90 +0. 80 +0. 70 +0. 60 +0. 50 +0. 40 +0. 30 +0. 20 +0. 10 Identical twins reared together Siblings reared apart Identical twins reared apart Unrelated children reared together Non-identical twins reared together Unrelated children reared apart Siblings reared together

Blastocyst Morula Cleavage Zygote Fertilization 3 4 5 Uterine wall 2 Fallopian tube Developing follicles 6 7 1 Implantation beginning Uterus Cervix Vagina Ovulation Mature follicle Ovary

The Germinal Stage of Prenatal Development Implantation of the Embryo Zygote Fallopian tube Ovary Uterus Embryo joined to uterine wall Cervix Blastocyst Vagina

Development During the Embryonic and Fetal Stages 15 weeks 4 weeks 7 weeks 6 ½ weeks 9 weeks

Centrifuge Uterine wall Chorion Amniotic fluid Placenta Cells Cell culture Cell Amniotic fluid Biochemical tests Chromosome analysis

Embryonic period (in weeks) 4 5 6 3 Central nervous system Eye Ear Heart 7 8 Fetal period (in weeks) 12 16 Full term 20 36 38 Brain Palate Ear Eye Heart Arm Leg Teeth External genitalia Central nervous system Heart Arms Eyes Legs Teeth Palate External genitalia Ear Period when major abnormality occurs Period when minor defect or abnormality occurs

Occupation Hazardous Substances Cleaning Personnel Soaps, detergents, solvents Electronic Assemblers Lead, tin, antimony, trichloroethylene, methyl chloride, resins Hair Dressers and Cosmetologists Hair-spray resins, aerosol propellants, solvents, dyes Health Personnel Anesthetic gases, x-rays, laboratory chemicals Painters Lead, titanium, toluene Photographic Processors Caustics, bromides, iodides, silver nitrate Plastic Workers Formaldehyde, vinyl chloride Printing Personnel Ink mists, methanol, carbon tetrachloride, lead, solvents, trichloroethylene Textile and Garment Workers Formadehyde, dyes, asbestos, solvents, flame retardants Transportation Personnel Carbon monoxide, lead

Nutritional Need Differences Between Nonpregnant and Pregnant Women (24 years old) Nutrient Folic acid Vitamin D Iron Calcium Phosphorus Pyridoxine Thiamin Zinc Riboflavin Protein Iodine Vitamin C Energy Magnesium Niacin Vitamin B-12 Vitamin A Nonpregnant 180 mcg 5 mg 15 mg 800 mg 1. 6 mg 1. 1 mg 12 mg 1. 3 mg 50 g 150 mcg 60 mg 2200 kcal 280 mg 15 mg 2. 0 mcg 800 mg Source: Data from Reece et al. , 1995. Pregnant 400 mcg 10 mg 30 mg 1200 mg 2. 2 mg 1. 5 mg 1. 6 mg 60 g 175 mcg 70 mg 2500 kcal 320 mg 17 mg 2. 2 mcg 800 mg Percent Dietary Sources Increase +122 +100 +50 +38 +36 +25 +23 +20 +17 +14 +13 +10 0 Leafy vegetables, liver Fortified dairy products Meats, eggs, grains Dairy products Meats, liver, enriched grains Enriched grains, pork Meats, seafood, eggs Meats, liver, enriched grains Meats, fish, poultry, dairy Iodized salt, seafood Citrus fruits, tomatoes Proteins, fats, carbohydrates Seafood, legumes, grains Meats, nuts, legumes Animal proteins Dark green, yellow, or orange fruits and vegetables, liver

Spine Coccyx Rectum Bladder Pubic bone Cervix Vagina Potential width of birth canal Water about to break (The baby's head now rests inside the cervix) The baby in the uterus before labor Transition: The baby in the birth canal STAGE 1 The baby about to be born The head rotates sideways after it emerges STAGE 2 The delivery of the placenta STAGE 3

Prenatal Risk Factors · Genetic Abnormalities (Down Syndrome, PKU, Huntington’s Disease, Sickle Cell, etc. ) · Teratogen Exposure (alcohol, drugs, AIDS, DES, tobacco, Thalidomide, etc. ) · Maternal Age (Over 40 or under 18) · Maternal Malnutrition · Low SES · Lack of Prenatal Care