Intro and prenatal development
- 2. Life Stages Life Stages: Infancy-birth to 1 year Early childhood- 1 to 6 years Middle childhood- 6 to 12 years Adolescence- 12 to 20 years Early adulthood - 20 to 40 years Middle adulthood- 40 to 65 years Late adulthood- 65 years and up
- 3. As individuals pass through these life stages, four main type of growth and development occur: 1. Physical: refers to body growth and includes height and weight changes, muscle and nerve development, and changes in body organs. 2. Mental: refers to development of the mind and includes learning how to solve problems, make judgments, and deal with situations.
- 4. 3. Emotional: refers to feelings and includes dealing with love, hate, joy, fear, excitement, and other similar feelings. 4. Social: refers to interactions and relationships with others
- 5. Forming a New Life Fertilization (conception) – union of sperm and ovum to produce a zygote. Zygote – celled organism resulting from fertilization. Dizygotic Twins (Fraternal Twins) – twins conceived by the two union of two different ova (a single ovum that has split) – no more alike genetically than any other siblings and need not even be of the same sex. Monozygotic Twins (Identical Twins) - twins resulting from the division of a single zygote after fertilization – genetically similar.
- 6. DNA, Genes and Chromosomes Deoxyribonucleic Acid (DNA) – chemical that carries inherited instructions for the development of all cellular forms of life. Genetic Code – sequence of bases within the DNA molecule; governs the formation of proteins that determine the structure and functions of living cells. Chromosomes – coils of DNA that consist of genes.
- 7. Genes – small segments of DNA located in definite positions on particular chromosomes; functional units of heredity. Human Genome – complete sequence of genes in the human body. Autosomes – in humans, the 22 pairs of chromosomes not related to sexual expression. Sex Chromosomes – pair of chromosomes that determines sex: XX in the normal human female, XY in the normal human male.
- 8. Sex Chromosome Abnormalities Pattern/ Name Typical Characteristics Incidence Treatment XXY Male: tall stature; tendency toward low IQ, especially verbal. 1 in 1,000 male births No special treatment XXX (triple X) Female: normal appearance, menstrual irregularities, learning disorders, mental retardation. 1 in 1,000 female births Special education XXY (kleinfelter) Male; sterility, underdeveloped secondary sex characteristics small testes, learning disorders. 1 in 1,000 male births Hormone therapy, special education XO (Turner) Female; short stature, webbed neck, impaired spatial abilities, no menstruation, infertility, underdeveloped sex organs, incomplete development of secondary sex characteristics. 1 in 1,500 to 2,500 female births Hormone therapy, special education Fragile X Minor-to-severe mental retardation; symptoms, which are more severe in males, include delayed speech and motor development, speech impairments, and hyperactivity: the most common inherited form of mental retardation 1 in 1,200 male births; 1 in 2,000 female births Educational and behavioral therapies when needed
- 10. PRENATAL DEVELOPMENT Gestation or Prenatal development – period of development between conception and birth; the process that transforms a zygote into a new-born. Gestational Age – age of an unborn baby, usually dated from the first day of an expectant mother’s last menstrual cycle.
- 11. THE NEED FOR PRECONCEPTION CARE: Care should begin before pregnancy to identify preventable risks. Types of care: Physical examination and the taking of medical and family histories Vaccinations for rubella and hepatitis B Risk screening for genetic disorders and infectious diseases such as STDs Counseling women to avoid smoking and alcohol, maintain a healthy body weight and take folic acid supplements
- 12. Symptoms of Pregnancy Physical Change Causes and Timing Tender, swollen breasts or nipples Increased production of the female hormones estrogen and progesterone stimulates breast growth to prepare for producing milk (most noticeable in a first preganancy). Fatigue: need to take extra naps Woman’s heart is pumping harder and faster to produce extra blood to carry nutrients to the fetus. Stepped-up production of hormones takes extra effort. Progesterone depresses central nervous system and may cause sleepiness. Concerns about pregnancy may sap energy. Slight bleeding or cramping Implantation bleeding may occur about 10 to 14 days after fertilization when fertilized ovum attaches to lining of uterus. Many women also have cramps (similar to menstrual cramps) as the uterus begins to enlarge. Food cravings Hormonal changes may alter food preferences, especially during first trimester, when hormones have greatest impact.
- 13. Symptoms of Pregnancy Physical Change Causes and Timing Nausea with or without vomiting Rising levels of estrogen produced by placenta and fetus cause stomach to empty more slowly. Also, heightened sense of smell may trigger nausea in response to certain odors, such as coffee, meat, dairy products, or spicy foods. Morning Sickness may begin as early as 2 weeks after conception, but usually around 4 to 8 weeks, and may occur at any time of day. Frequent urination Enlarging uterus during first trimester exerts pressure on the bladder. Frequent, mild headaches Increased blood circulation caused by hormonal changes may bring these on.
- 14. Symptoms of Pregnancy Physical Change Causes and Timing Constipation Increase in progesterone may slow digestion, so food passes more slowly through intestinal tract. Mood swings Flood of hormones early in pregnancy can produce emotional highs and lows. Faintless and dizziness Lightheaded feeling may be triggered by blood vessel dilation and low blood pressure or by low blood sugar. Raised basal body temperature Basal body temperature (taken first thing in the morning) normally rises soon after ovulation each month and then drops during menstruation. When menstruation ceases, temperature remains elevated.
- 15. Stages of Prenatal Development Germinal Stage – first two weeks of prenatal development, characterized by rapid cell division, blastocyst formation, and implantation in the wall of the uterus.
- 16. Embryonic stage Second stage of gestation (2 to 8 weeks), characterized by rapid growth and development of major body systems and organs. This is a critical period, when the embryo is most vulnerable to destructive influences in the prenatal environment. The most severely defective embryos usually do not survive beyond the first trimester or 3-month period of pregnancy.
- 17. Fetal stage (8 weeks to birth) Final stage of gestation from 8 weeks to birth, characterized by increased differentiation of body parts and greatly enlarged body size. During this period, the fetus grows rapidly to about 20 times its previous length and organs and body systems become more complex. Right up to birth, “finishing touches” such as fingernails, toenails, and eyelids continue to develop.