Module 36 37 38 02 05 2012 Module 36 Prenatal Development Conception to Birth The basics of genetics the blood stream The earliest development Chromosomes rod shaped structures that contain all basic hereditary information 23 pairs in each pair on is from the mother the other is from the father each contains thousands of Genes the parts of the chromosomes through which genetic information is transmitted produce each person s particular characteristics The human genome project o 2001 mapped the specific location and sequence of every human gene o started a revolution in health care because scientists can identify the particular genes responsible for genetically caused disorders o gene therapy inject genes to correct particular diseases into cells zygote the new cell formed by the union of an egg and sperm germinal period first 2 weeks as the zygote exponentially grows in embryonic period from week 2 to week 8 grows very large and begins to develop discernable body parts embryo a developed zygote that has a heart a brain and other organs fetal period from week 8 and continuing until birth responds to touch facial features major organs will begin functioning fetus a developing individual from 8 weeks after conceptions until birth age of viability the point at which a fetus can survive of born prematurely prenatal age of 22 weeks sensitive periods time when organisms are particularly susceptible to certain kinds of stimuli preterm infants born before week 38 less developed higher risk for illness future problems and even death Genetic Influence on the Fetus Prental environmental influences Phenylketonuria PKU cannot produce an enzyme that is required for normal development results in an accumulation of poisons that result in mental retardation treatable if caught early Sickle cell anemia 10 of the African American population has the gene abnormally shaped red blood cells results in episodes of pain yellowish eye stunted growth and vision problems Tay sachs disease found in Jews die by 3 4 because of inability to break down fat if both parents carry it their child has a chance of getting it Down syndrome causes of mental retardation zygote receives an extra chromosome at the moment of conception often related to the mother s age above 35 and younger than 18 Teratogens environmental agents such as a drug chemical virus or other factor that produce a birth defect Mother s nurtrition need to be well nourished to provide adequate nutrition to the fetus poorly nourished babies are more susceptible to disease Mother s illness sometimes can have no effect on mother but devastating consequences for the developing fetus if contracted during the early part of pregnancy Mother s emotional state autonomic nervous system of the fetus becomes especially sensitive as a result of chemical changes produced by the mother s emotional state Mother s use of drugs mother s who are addicted run the risk of giving birth to babies who are also addicted Alcohol extremely dangerous to fetal development fetal alcohol syndrome results in below average intelligence growth delays and facial deformities Nicotine use can lead to miscarriage and death Alternative paths to conception In vitro fertilization women s eggs are removed and a man s sperm is used to fertilize the eggs in the lab and then it is implanted into the women s uterus Gamete intrafallopian transfer and zygot intrafallopian transfer egg and sperm or fertilized egg is implanted in a woman s fallopian tubes Surrogate mother a woman who agrees to carry the child to term Module 37 Infancy and Childhood Neonate a newborn child covered in vernix a white greasy covering for protection before birth and languo a soft fuzz over the entire body The Extraordinary Newborn Reflexes unlearned involuntary responses the occur automatically in the presence of certain stimuli o Rooting relex turn their head towards thngs that touch their cheek their lips noise o Sucking reflex prompts infants to suck at things that touch o Gag relflex to clear the throat o Startle reflex flings arms out and arches back to a sudden o Babinski reflex toes fan out when the outer edge of the sole of the foot is stroked o Infants lose the reflexes after the first few months of life and replace them with more complex and organized behaviors Rolls over by 3 months Sits by 6 months Stands alone by 11 months And walks when 1 year old Development of the senses o Using a testing method of habituation decrease in the response to a stimulus that occurs after repeated presentations of the same stimulus o Showed that infants visual perception is remarkably sophisticated can discriminate facial expressions and imitate them o Can distinguish their mother s voice from others and distinguish languages o They can also recognize different tastes and smells Infancy through Childhood Physical Development o Triple in weight and double in height by the first year o Rapid growth slows as they get older average gain of 5 pounds and 3 inches a year o Relationship of size of various body parts to one another changes Development of Social Behavior o Attachment the positive emotional bond that develops between a child and a particular individual Lorenz newborn goslings that followed him imprinting the behavior that takes place during a critical period and involves attachment to the first moving object that is observed Harlow newborn monkeys more attached to terry cloth warm monkey than wire breast feeding monkey The greater the responsiveness of the caregiver s responsiveness to the child s signals the more likely the child will become securely attached o Assessing attachment Ainsworth strange situation leaving babies in a room with a stranger and then returning the baby to its mother Securely attached will cry when she leaves and then immediately return to her Avoidant children do not cry when she leaves and seem to avoid her when she returns Ambivalent anxiety when separated but show ambivalent actions when she returns Disorganized disoriented children show inconsistent and contradictory behavior Securely attached tend to be more social and have less psychological problems but does not a guarantee a good adjustment later o Father s Role Fathers are more physical and rough tumble Can still form connections like mothers o Social relationships with peers By the time they are 2 they prefer to play with friends Initially just playing side by side but then begin to play with each other Social interaction helps children
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