Child Development unit 2 PDF

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CHILD DEVELOPMENT: Stages Of Span Development: Prenatal Development, Birth and Infancy, Childhood, Adolescence, Adulthood. 88-117 Chap 4 Chap 5 203-215 PRENATAL DEVELOPMENT: Prenatal development is defined as the process of growth and development within the womb from fertilization until birth. CONCEPTION: Conception occurs when a sperm cell from a fertile man swims up through the vagina and into the uterus of a woman and joins with the woman’s egg cell as it travels down one of the fallopian tubes from the ovary to the uterus. Conception process begins with ovulation, when an ovum, or egg, which has been stored in one of the female’s two ovaries, matures and is released into the fallopian tube. Ovulation occurs about halfway through the woman’s menstrual cycle and is aided by the release of a complex combination of hormones. In addition to helping the egg mature, the hormones also cause the lining of the uterus to grow thicker and more suitable for implantation of a fertilized egg. The male produces sperm in vast numbers—an average of 300 million a day. After the intercourse, sperm deposited by the man’s ejaculation, which are travelling up the fallopian tube, may fertilize the egg. When a sperm cell joins with an egg, it’s called fertilization. The vast changes that take place during the 38 weeks of pregnancy are usually divided into three periods: (1) the period of the zygote, (2) the period of the embryo, and (3) the period of the fetus. Stage 1 : Zygote (2 weeks) Within several hours of conception, half of the 23 chromosomes from the egg and half of the 23 chromosomes from the sperm fuse together, creating a zygote — a fertilized ovum. The period of the zygote lasts about two weeks, from fertilization until the tiny mass of cells drifts down and out of the fallopian tube and attaches itself to the wall of the uterus. Rapid cell division occurs and by the fourth day, 60 to 70 cells exist that form a hollow, fluid-filled ball called a blastocyst. The cells on the inside of the blastocyst, called the embryonic disk , will become the new organism; the thin outer ring of cells, termed the trophoblast , will become the structures that provide protective covering and nourishment. Theb l a s t oc y s ta r r i v e sa tt heut e r usa nda t t a c h e st ot heut e r i newa l l ,apr oc e s skno wna si mpl a nt a t i o n. I mpl a nt a t i o no c c u r swhe nt h ec e l l sn e s t l ei n t ot h eu t e r i n el i ni n ga ndr up t u r et i n ybl oodv e s s e l s . The c o nne c t i v ewe bofbl oodv e s s e l sa ndme mb r a ne st h a tf or mb e t we e nt he m wi l lpr o vi denour i s h me ntf or t hede v e l opi n gbe i n gf ort hene xtni n emon t hs .Amnion, a protective membrane, encloses the developing organism in amniotic fluid , which helps keep the temperature of the prenatal world constant and provides a cushion against any jolts caused by the woman’s movement. Another protective membrane, chorion, develops placenta, which is an organ that allows the exchange of nutrients between the embryo and the mother, while at the same time filtering out harmful material. The filtering occurs through a thin membrane that separates the mother’s blood from the blood of the fetus, allowing them to share only the material that is able to pass through the filter. Finally, the umbilical cord, which links placenta to the developing organ, transfers all material to the fetus. It

contains one large vein that delivers blood loaded with nutrients and two arteries that remove waste products. Thus the placenta and the umbilical cord protect the fetus from many foreign agents in the mother’s system that might otherwise pose a threat. Stage 2 Embryo (lasts about 6 weeks) Theb e gi nn i n goft het h i r dwe e ka f t e rc onc e pt i onma r kst hes t a r to ft h ee mb r y oni cp e r i od,at i mewhe n t hema s so fc e l l sb e c ome sd i s t i nc ta sah uma n.Du r i n gt h i ss t a g e , whi c hlasts from implantation through the eighth week of pregnancy, the most rapid prenatal changes take place, as the groundwork is laid for all body structures and internal organs. In the first week of this period, the embryonic disk forms three layers of cells: the ectoderm , which will become the nervous system and skin; (2) the mesoderm , from which will develop the muscles, skeleton, circulatory system, and other internal organs; and (3) the endoderm , which will become the digestive system, lungs, urinary tract, and glands. These three layers give rise to all parts of the body. Ar oundt h ef our t hwe e k,t hehe a db e gi n st of or m, q u i c kl yf o l l o we db yt hee y e s ,n os e , e a r s , a ndmo ut h. Theb l oodv e s s e lt ha twi l lb e c o met h ehe a r ts t a r tt op ul s e .Heart develops separate chambers, and the liver and spleen take over production of blood cells so that the yolk sac is no longer needed Dur i n g t hefif t hwe e k, bu dst h a twi l lf or mt hea r msa ndl e gsa ppe a r .At seventh weeks, production of neurons (nerve cells that store and transmit information) begins deep inside the neural tube. Once formed, neurons begin traveling along tiny threads to their permanent locations, where they will hee ndo ft hee mbr y oni cpe r i od, t heba s i cs t r uc t ur e soft h e form the major parts of the brain. Byt br a i na ndc e nt r a lne r v ouss y s t e mh a v ebe e ne s t a bl i s he d. Thee mb r y oi sn o wapproximately 1 inch long and 1⁄7 ounce in weight and can already sense its world. Stage 3 Fetus The period of the fetus, from the ninth week to the end of pregnancy, is the longest prenatal period. During this “growth and finishing” phase, the organism increases rapidly in size, especially from the ninth to the twentieth week. Byt heni nt hwe e k, the organs, muscles, and nervous system start to become organized and connected and r e fle x e sb e g i nt oe me r g e .Thef e t u sbe gi nst oma k er e fle x i v emo t i o n swi t hi t sa r msa n d l e g s . The tiny lungs begin to expand and contract in an early rehearsal of breathing movements. By the twelfth week, the external genitals are well-formed, and the sex of the fetus can be detected with ultrasound. Other finishing touches appear, such as fingernails, toenails, tooth buds, and ee n doft het hi r dmo nt ha l s o eyelids. The heartbeat can now be heard through a stethoscope. Th ma r kst h ee n do ft hefir s tt r i me s t e rofpr e gna nc y . By the middle of the second trimester, between 17 and 20 weeks, the new being has grown large enough that the mother can feel its movements. A white, cheeselike substance called vernix covers the skin, protecting it from chapping during the long months spent in the amniotic fluid. White, downy hair called lanugo also covers the entire body, helping the vernix stick to the skin. Many organs are well developed by the end of second trimester, however, glial cells, which support and feed the neurons, continue to increase rapidly throughout the remaining months of pregnancy, as

well as after birth. Neurons also, begin forming synapses, or connections, at a rapid pace. By this time, the baby can hear (and recognize) sounds and respond to light. The third trimester begins in week 28 of pregnancy and lasts until birth. . The point at which the baby can first survive, called the age of viability, occurs sometime between 22 and 26 week. A baby born between the seventh and eighth months, however, usually needs oxygen assistance to breathe…………………………………………………

v i r onme nt a lv a r i a b l e sc a na l s opl a yama j o rr ol ei npr e na t a l Prenatal environmental influences: En de v e l o pme n t . Teratogen refers to any environmental agent that causes damage during the prenatal period. In the period of the zygote , before implantation, teratogens rarely have any impact. If they do, the tiny mass of cells is usually so damaged that it dies. The embryonic period is the time when serious defects are most likely to occur because the foundations for all body parts are being laid down. During the fetal period , teratogenic damage is usually minor. However, organs such as the brain, ears, eyes, teeth, and genitals can still be strongly affected. The harm done by teratogens is not always simple and straightforward. It depends on the following factors: Dose: larger doses over longer time periods usually have more negative effects. Heredity . The genetic makeup of the mother and the developing organism plays an important role. Some individuals are better able than others to withstand harmful environments. Other negative influences . The presence of several negative factors at once, such as additional teratogens, poor nutrition, and lack of medical care, can worsen the impact of a single harmful agent. Age . The effects of teratogens vary with the age of the organism at time of exposure.

Variety of teratogens: 1) Prescription and Nonprescription Drugs: Many prescription and nonprescription medications can impair embryonic and fetal development. About 70% of pregnant women take at least one prescription drug. Prescription drugs can cause birth defects, problems in overall health, and development of the fetus. In the early 1960s, sedative called thalidomide was widely taken by mother in Canada, Europe, and South America. About 7,000 infants worldwide were affected. thalidomide produced gross deformities of the embryo’s developing arms and legs and, less frequently, damage to the ears, heart, kidneys, and genitals. It also affected child’s average intelligence in its later years. Another medication, a synthetic hormone called diethylstilbestrol (DES) , was widely prescribed between 1945 and 1970 to prevent miscarriages. As daughters of these mothers reached adolescence and young adulthood, they showed unusually high rates of cancer of the vagina, malformations of the uterus, and infertility. When they tried to have children, their pregnancies more often resulted in prematurity, low birth weight, and miscarriage than those of nonDES-exposed women. Currently, the most widely used potent teratogen is a vitamin A derivative called Accutane (known by the generic name isotretinoin ), . Exposure during the first trimester of

pregnancy results in eye, ear, skull, brain, heart, and immune system abnormalities. many pregnant women continue to take over-the-counter medications without consulting their doctors. Aspirin is one of the most common, is linked to low birth weight, infant death around the time of birth, poorer motor development, and lower intelligence test scores in early childhoodCoffee, tea, cola, and cocoa contain another frequently consumed drug, caffeine, which could lead to low birth weight and miscarriage Antidepressant medications are linked to increased risk of premature delivery and birth complications, including respiratory distress and persistent high blood pressure in infancy. 2) illegal drugs: Theus eo fhighly addictive mood-altering drugs, such as cocaine and heroin, b yt he mot he rc a nh a v ed e v a s t a t i n gc ons e q ue nc e st ot h ef e t us .Babies born to users of cocaine, heroin, or methadone are at risk for a wide variety of problems, including pre maturity, low birth weight, physical defects, breathing difficulties, and death at or around the time of birth. Throughout the first year, heroin- and methadone-exposed infants are less attentive to the environment than nonexposed babies, and their motor development is slow. Another commonly used illegal drug is, marijuana. prenatal marijuana exposure is linked to smaller head size (a measure of brain growth); to attention, memory, and academic achievement difficulties; to impulsivity and overactivity; and to depression as well as anger and aggression in childhood and adolescence. 3) Tobacco: Another widely used teratogen is tobacco. The best-known effect of smoking during the prenatal period is low birth weight. other serious consequences of tobacco are miscarriage, prematurity, cleft lip and palate, impaired heart rate and breathing during sleep, infant death, and asthma and cancer later in childhood. Nicotine, the addictive substance in tobacco, constricts blood vessels, lessens blood flow to the uterus, and causes the placenta to grow abnormally. This reduces the transfer of nutrients, so the fetus gains weight poorly. Also, nicotine raises the concentration of carbon monoxide in the bloodstreams of both mother and fetus. Carbon monoxide displaces oxygen from red blood cells, damaging the central nervous system and slowing body growth in the foetuses. 4) Alcohol: One of the most commonly used teratogens is alcohol. Alcohol interferes with production and migration of neurons in the primitive neural tube. EEG and fMRI research reveals reduced brain size, damage to many brain structures, and abnormalities in brain functioning, including the electrical and chemical activity involved in transferring messages from one part of the brain to another. Also, the body uses large quantities of oxygen to metabolize alcohol. A pregnant woman’s heavy drinking draws away oxygen that the developing organism needs for cell growth. Alcohol consumption can result in, fetal alcohol syndrome (FAS), a condition caused by maternal alcohol drinking that can lead to numerous detrimental developmental effects, including limb and facial abnormalities, genital anomalies, and mental retardation. Children with FASD are given one of three diagnoses, which vary in severity: 1. Fetal alcohol syndrome (FAS), distinguished by (a) slow physical growth, (b) a pattern of three facial abnormalities (short eyelid openings; a thin upper lip; a smooth or flattened philtrum, or indentation running from the bottom of the nose to the center of the upper lip), and (c) brain injury, evident in a small head and impairment in at least three areas of functioning—for example, memory, language and communication, attention span and activity level (overactivity), planning and reasoning, motor coordination, or social skills. 2. Partial fetal alcohol syndrome (p-FAS), characterized by (a) two of the three facial abnormalities just mentioned and (b) brain injury, again evident in at least three areas of impaired functioning.

Mothers of children with p-FAS generally drank alcohol in smaller quantities, and children’s defects vary with the timing and length of alcohol exposure. 3. Alcohol-related neurodevelopmental disorder (ARND), in which at least three areas of mental functioning are impaired, despite typical physical growth and absence of facial abnormalities. Again, prenatal alcohol exposure, though confirmed, is less pervasive than in FAS 5) Radiation:

6) Environmental pollution: researchers quote that many babies are “born polluted” by chemicals that not only impair prenatal development but also increase the chances of health problems and lifethreatening diseases later on. Prenatal exposure to traffic-related air pollution due to residence near roadways, for example, is linked to lower birth weight, with complicated pregnancies at greater risk. Mercury – physical deformities, mental retardation, abnormal speech, difficulty in chewing and swallowing, and uncoordinated movements. High levels of prenatal mercury exposure disrupt production and migration of neurons, causing widespread brain damage. PCB – prenatal exposure to very high levels of PCBs in rice oil resulted in low birth weight, discolored skin, deformities of the gums and nails, EEG brainwave abnormalities, and delayed cognitive development. Lead – High levels of prenatal lead exposure are consistently related to prematurity, low birth weight, brain damage, poorer mental and motor development and a wide variety of physical defects. dioxins —toxic compounds resulting from incineration— is linked to brain, immune system, and thyroid damage in babies and to an increased incidence of breast and uterine cancers in women. 7) Maternal Disease: A number of maternal diseases can negatively impact the fetus, including herpes, rubella, and AIDS. Rubella: Rubella, also called German measles, is an infection that causes mild flu-like symptoms and a rash on the skin. Rubella has been associated with a number of birth defects. If the mother contracts the disease during the first three months of pregnancy, damage can occur in the eyes, ears, heart or brain of the unborn child. Deafness is almost certain if the mother has German measles before the 11th week of prenatal development and can also cause brain damage. The human immunodeficiency virus (HIV) , which can lead to acquired immune deficiency syndrome (AIDS) , a disease that destroys the immune system. One of the main ways children under age 13 become infected with HIV is via mother-to-child transmission of the virus prenatally, during labor, or by breastfeeding. Herpes virus is one of the most common maternal diseases and can be transmitted to the fetus, leading to deafness, brain swelling, or intellectual disability. Women with herpes virus are often encouraged to deliver via cesarean to avoid transmission of the virus. Bacterial and Parasitic Diseases: The tiny parasite, toxoplasma gondii, causes an infection called Toxoplasmosis. Toxoplasmosis can cause premature birth, stillbirth, and can result in birth defects to the eyes and brain. While most babies born with this infection show no symptoms, ten percent may experience eye infections, enlarged liver and spleen, jaundice, and pneumonia. Other maternal factors:

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Exercise Nutrition Emotional stress Maternal age

CHILDBIRTH: Childbirth, also known as labour and delivery, is the ending of pregnancy where the baby leaves the uterus by passing through the vagina and in some cases, Caesarean section. 3 stages: 1. Dilation and effacement of the cervix. This is the longest stage of labor, lasting an average of 12 to 14 hours with a first birth and 4 to 6 hours with later births. Contractions of the uterus gradually become more frequent and powerful, causing the cervix, or uterine opening, to widen and thin to nothing, forming a clear channel from the uterus into the birth canal, or vagina 2. Delivery of the baby. This second stage is much shorter than the first, lasting about 50 minutes for a first baby and 20 minutes in later births. Strong contractions of the uterus continue, but the mother also feels a natural urge to squeeze and push with her abdominal muscles. As she does so with each contraction, she forces the baby down and out. 3. Birth of the placenta. Labor comes to an end with a few final contractions and pushes. These cause the placenta to separate from the wall of the uterus and be delivered in about 5 to 10 minutes. Baby’s adaption to labor and delivery: During childbirth, high levels of infant cortisol and other stress hormones are adaptive. They help the baby withstand oxygen deprivation by sending a rich supply of blood to the brain and heart. Stress hormones prepare the baby to breathe by causing the lungs to absorb any remaining fluid and by expanding the bronchial tubes. Stress hormones also arouse infants into alertness so they are born wide awake, ready to interact with their world. Assessing the Newborn’s Physical Condition: To assess the baby’s physical condition, doctors and nurses use the Apgar Scal. Apgar stands for "Appearance, Pulse, Grimace, Activity, and Respiration. The Apgar score checks 5 characteristics of the baby. These are:     

skin colour heart rate reflexes and responsiveness muscle tone breathing rate

Score of 7 or better: good condition

Score between 4 and 6: baby needs assistance Score of 3 or lower: baby is in serious danger and needs medical attention...