Reproduction, Heredity and Genetics, and Prenatal Development Chapter 3 Reproduction, Heredity and Genetics, and Prenatal Development

Reproduction Process by which organisms create more organisms of own kind. Male and female gametes or sex cells: Sperm and ovum create zygote

Male Reproductive System Testes: produce sperm Penis: Man’s external organ

The Female Reproductive System Ovaries produce ova. Ovum released approximately every 28 days. Moves through fallopian tubes where it may be fertilized by sperm. Uterus prepares itself for conception. Unfertilized ovum shed; expelled through cervix and vagina.

How and When Fertilization Occurs Menstrual Cycle Ovulation Fertilization Multiple Conception

Conceiving or Avoiding Conception Infertility and Assisted Reproductive Technology In Vitro Fertilization Ethical Dilemmas of Baby Making Birth Control Methods a. Contraception b. Abortion

Infertility and Assisted Reproductive Technology In vitro fertilization (IVF) Gamete intrafallopian transfer (GIFT) Zygote intrafallopian transfer (ZIFT) Intracytoplasmic sperm injection (ICSI) Preimplantation genetic treatment (PGT) Ovarian and sperm cryopreservation Sperm sorting (sperm separation) Embryo adoption

Ethical Dilemmas of Baby Making ARTs have significantly improved pregnancy rates Questions: How long should embryos develop in lab? Who do embryos belong to? What type of research is being conducted?

Birth Control Methods Abstinence Contraception Abortion

The Expanding Reproductive Years Menstruation can begin at 8 or 9 years of age; average 11 to 12 Advanced technology allows women to choose childbearing after menopause.

Heredity and Genetics Heredity: our biological inheritance Genetics: the scientific study of biological inheritance

The Human Genome Project The sequencing of the genetic blueprint of all the genes on their appropriate chromosomes Genome is divided into chromosomes Chromosomes contain genes Genes are made of DNA

What are Chromosomes and Genes? DNA Human genome Mitosis Meiosis

Determination of an Embryo’s Sex 46 chromosomes (23 pairs) 22 are similar in size and shape in both men and women: autosomes 23rd pair: sex chromosome, determines baby’s sex.

Principles of Genetics Gregor Johann Mendel Dominant and Recessive Characteristics a. Allele (dominant or recessive) b. Homozygous characteristic c. Heterozygous characteristics d. Polygenic inheritance

Phenotypes and Genotypes Genotype: Actual genetic makeup of organism Phenotype: Observable characteristics of organism

Multifactorial Transmission Environmental factors interact with genetic factors to produce traits. Sex-Linked Inherited Characteristics: Genes that are linked or appear on the same chromosome are inherited together: Sex-linked traits.

Genetic Counseling and Testing Genetic Counseling: Helps parents find out risk of passing along a particular disorder or disease.

Genetic and Chromosomal Abnormalities Downs’ Syndrome: Occurs in 1 out of every 800 live births. In 95% of all cases there are three copies of the 21st chromosome: trisomy 21 Extra chromosome alters course of development and causes physical characteristics.

Box: Human Diversity Prenatal diagnosis: Amniocentesis Ultrasonography Fetoscopy Chorionic villus biopsy Maternal blood sampling

Prenatal Development Germinal Period: From conception to second week. Characterized by growth of zygote and establishment of linkage between zygote and support system of mother.

Embryonic Period From end of second week to eighth week. Rapid growth Establishment of a placental relationship with mother Early structural appearance of all chief organs Development of recognizable human body.

Development during embryonic period Cephalocaudal Proximodistal Critical Period

Fetal Period Begins with the ninth week and ends with birth Characteristics: Organism called a fetus Major organ systems continue to develop and assume their specialized functions.

Loss by Miscarriage Miscarriage: organism is naturally expelled from uterus before it is viable.

Prenatal Environmental Influences Teratogens: Drugs and other chemical agents that can cause birth defects: Smoking Marijuana Hard Drugs Alcohol Oral Contraceptives Toxins in environment and workplace

Maternal Infectious and Noninfectious Diseases: Rubella and Other Agents Syphilis Genital Herpes HIV/AIDS Diabetes Maternal Sensitization: The Rh Factor Maternal Stress Maternal Age Maternal Nutrition and Prenatal Care