What are the three areas of change that developmental psychologists study? Developmental psychologists study: 1. Physical (growth and development of skills) 2. Mental( intellect and cognitive skills) 3. and social (relationships and connections to others) changes throughout the life cycle. What are three major issues in developmental psychology? BIG ISSUES Developmental Psychology Issue Nature/Nurture Continuity/Stages Stability/Change Details How do genetic inheritance (our nature) and experience (the nurture we receive) influence our behavior? Is developmental a gradual, continuous process or a sequence of separate stages? Do our early personality traits persist through life, or do we become different persons as we age. 6 Prenatal development We don't often discuss prenatal physical development in psychology courses, but I think that's really inexcusable. Fetal Development Stage Length of time Conception Zygote Embryo Fetus Neonate FAS Teratogen Description How does human conception occur? A total of 200 million or more sperm deposited during intercourse approach the egg 85,000 times their own size. The few that make it to the egg release digestive enzymes that eat away the egg’s protective coating, allowing a sperm to penetrate. The egg’s surface blocks out all others and within a half day, the egg nucleus and the sperm nucleus fuse. http://www.metacafe.com/watch/4038085/prenatal_development/ In the Womb – National Geographic http://video.nationalgeographic.com/video/player/national-geographic-channel/allvideos/av-5243-5543/ngc-inside-the-womb.html Conception: Female releases egg / OVA (HAVE 500 at birth) and meets with up to 2 million sperm (male begins producing at puberty) released during intercourse. Conception A single sperm cell (male) penetrates the outer coating of the egg (female) and fuse to form one fertilized cell. Lennart Nilsson/ Albert Bonniers Publishing Company Lennart Nilsson/ Albert Bonniers Publishing Company 8 1. After sexual intercourse, sperm travels through the cervix and uterus and into the Fallopian tubes. 2. Conception usually takes place in the outer third of the Fallopian tube. 3. A single sperm penetrates that egg (up to 100 try) and a joining of the genetic information occurs. 4. This resulting single cell is called a zygote: < ½ of all fertilized eggs become a zygote. 5. Cells then differentiate to become intestine and brains, etc. 6. 10 days, attach to uterine wall for next 37 weeks = embryo 7. 9 weeks - birth = fetus Zygote (10 days) --- Embryo (approx. 2-9 wks) --- Fetus (2 - 37 weeks /birth) Define zygote, embryo, and fetus, and explain how teratogens can affect development. OF Note - Fewer than half of fertilized eggs, called zygotes, survive. 1. In the first week, cell division produces a zygote of some 100 cells, which are already beginning to differentiate, to specialize in structure and function. 2. About 10 days after conception, the zygote’s outer part attaches to the uterine wall and becomes the placenta through which nourishment passes. 3. The inner cells become the embryo. 4. FETAL STAGE = by 9 weeks after conception, the embryo looks unmistakably human and is now a fetus. 5. During the sixth month, internal organs such as the stomach have become sufficiently formed and functional to allow a prematurely born fetus a chance of survival. 6. 25 weeks gestation 7. At each prenatal stage, genetic and environmental factors affect development. 8. Along with nutrients, teratogens ingested by the mother can reach the developing child and place it at risk. 9. If the mother drinks heavily, the effects may be visible as fetal alcohol syndrome (FAS). 10. AT each prenatal stage, genetic and environmental factors, germs and virus’s, can slip through the placenta and affect development. This is called TERATOGENS. Teratogens is a medical term from the Greek, literally meaning monster Teratogen - A drug or other substance capable of interfering with the development of a fetus, causing birth defects. FAS Drinking during pregnancy can lead to a range of physical, learning, and behavioral effects in the developing brain, the most serious of which is a collection of symptoms known as fetal alcohol syndrome (FAS). Children with FAS may have distinct facial features. FAS infants also are markedly smaller than average. Their brains have less volume (i.e., microencephaly). And they have fewer numbers of brain cells (i.e., neurons) or fewer neurons that are able to function correctly, leading to long–term problems in learning and behavior. It is during this critical period of differentiation (most of the first trimester or threemonth period) that the growing fetus is most susceptible to damage from external sources (teratogens) including viral infections such as rubella, x-rays and other radiation, and poor nutrition. http://embryology.med.unsw.edu.au/wwwhuman/Stages/CStages.htm Handout Known teratogens: The American College of Occupational and Environmental Medicine recognizes the following teratogens. Smoking: fetus gets fewer nutrients leading to underweight babies Ionizing radiation: atomic weapons, radiation therapy Infections: herpes virus , , rubella virus (German measles), syphilis, Venezuelan equine encephalitis virus Metabolic imbalance: diabetes, folic acid deficiency, hyperthermia, rheumatic disease and congenital heart block FAS /Fetal Alcohol Syndrome (there is no known SAFE amout od alcohol known for pregnant females) 4 in 10 alcoholic mothers have an FAS child at birth As a result - 1: 750 will suffer: small mis proportioned head, lifelong brain abnormalities, Leading cause of mental retardation Drugs and environmental chemicals: Accutane, androgenic hormones, busulfan, ACE inhibitors, cocaine, lithium, organic mercury compounds, penicillamine, tetracyclines, thalidomide, trimethadione, valproic acid. A child who has one developmental problem may have other problems that arose at the same time: Kidney problems and hearing problems, for example, are often found together because both kidneys and the inner ears develop at the same time. Week 3 we see the formation of the heart, the beginning development of the brain and spinal cord, and the beginning of the gastrointestinal tract. * Teratogens introduced during this period may cause severe problems such as the absence of one or more limbs or a heart that is outside of the chest cavity at birth. Drugs crossing the placenta: Thalidomide is a drug that was sold during the late 1950s and 1960s as a sleeping aid and to pregnant women as an antiemetic to combat morning sickness and other symptoms. Caused severe limb malformation or the absence of limbs Weeks 4 and 5 --1/4 inch long; child is the size of a grain of rice * Here we see the beginnings of the vertebra, the lower jaw, the larynx (voice box), and the rudiments of the ear and eye. * The heart, which is still outside body, now beats at a regular rhythm. * Although arm and leg "buds" are visible with hand and foot "pads," the embryo still has a tail and cannot be distinguished from pig, rabbit, elephant, or chick embryo. * Teratogens may cause very serious problems involving the esophagus, vertebrae, eyes. The baby could be born with severe facial clefts or missing hands or feet. Week 6 -- 1/2 inch, 1/1000 of an ounce; child = the size of a tip of a q-tip * We see the formation of the nose, jaw, palate, lung buds. * The fingers and toes form, but may still be webbed. * The tail is receding, and the heart is almost fully developed. * Teratogens at this point may leave the baby with profound heart problems or a cleft lip. Week 7 -- 7/8 inch, 1/30 ounce; Circumference of an AA battery * This week, the eyes move forward on the face, and the eyelids and tongue begin to form. * All essential organs have begun to form. * Teratogens may cause heart and lung problems, a cleft palate, and ambiguous genitalia (not quite male or female). Week 8 --1 inch, 1/15 ounce; Pointer finger to knuckle * The embryo now resembles a human being. * The facial features continue to develop and the external ear appears. * Also, we see the beginnings of external genitalia. * By now, the circulation through the umbilical cord is well developed. * The long bones begin to form and the muscles are able to contract. * Teratogens may still cause heart problems and stunting of the fingers and toes. The Fetus: At this point the embryo is developed enough to call a fetus. All organs and structures found in a full-term newborn are present. Weeks 9 to 12 -- 3 inches, 1 ounce: size = 4 fingers w/o thumb * The head comprises nearly half of the fetus’ size and the face is well formed. * The eyelids close now and will not reopen until about the 28th week. * The tooth buds for the baby teeth appear. * The genitalia are now clearly male or female. Weeks 13 to 16 -- 6 inches; size = Average length of a pen * These weeks mark the beginning of the second trimester. * Although the skin of the fetus is almost transparent, fine hair develops on the head called lanugo. * The fetus makes active movements, including sucking, which leads to some swallowing of the amniotic fluid. * A thin dark substance called meconium is made in the intestinal tract. * The heart beats120-150 beats per minute and brain waves detectable. Weeks 17 to 20 -- 8 inches; size = Width of your PSI book * Eyebrows and lashes appear and nails appear on fingers and toes. * This is an exciting time for the parents: The can mother feel the fetus moving ("quickening") and the fetal heartbeat can be heard with a stethoscope. Weeks 21 to 24 -- 11.2 inches, 1 lb. 10 oz; Length of a piece of paper * All the eye components are developed, footprints and fingerprints are forming, and the entire body covered in cream-cheese-like vernix caseosa. * The fetus now has a startle reflex. Weeks 25 to 28 -- 15 inches, 2 lbs. 11 oz.: Width of computer monitor / media center * Now we are entering the third trimester. * During these weeks, we see rapid brain development. * The nervous system is developed enough to control some body functions, and the eyelids open and close. * A baby born at this time may survive, but the chances of complications and death are high. Weeks 29 to 32 -- 15 -17 inches, 4 lbs. 6 oz: Fingers to elbow * These weeks see further development towards independent life: * There is a rapid increase in the amount of body fat and the fetus begins storing its own iron, calcium, and phosphorus. * The bones are fully developed, but still soft and pliable. * There are rhythmic breathing movements present, the fetal body temperature is partially self-controlled, and there is increased central nervous system control over body functions. Weeks 33 to 36 -- 16 -19 inches, 5 lbs. 12 oz. to 6 lbs. 12 oz: Shoulder to hip * The lanugo (body hair) begins to disappear. * A baby born at 36 weeks has a high chance of survival. Weeks 37 to 40 -- 19 - 21 inches 7 or 8 pounds * At 38 weeks, the fetus is considered full term. * It fills the entire uterus, and its head is the same size around as its shoulders. * The mother supplies the fetus with the antibodies it needs to protect it against disease. Birth: Birth has nearly as many dangers as the embryonic stage, mostly from infections and anoxia. * Anoxia means "no oxygen," and can be due to a number of situations: * If something prevents the exchange of blood from mother to child prior to the baby breathing on its own, the lack of oxygen quickly begins to take its toll, especially on the brain. * This is called cord strangulation, and it can be caused by the cord being pressed between the baby's head and the mother's pelvis. * A breech birth, which involves the baby's buttocks going first instead of its head, can slow the birth process. * And premature separation of the placenta from the mother's uterus can cause anoxia as well.