<strong>Ozean</strong> Journal of Social Sciences 2(3), 2009<strong>Ozean</strong> Journal of Social Sciences 2(3), 2009ISSN 1943-2577© 2009 <strong>Ozean</strong> PublicationA REVIEW OF THE PROBLEMS ASSOCIATED WITH PHYSICAL DEVELOPMENTOF HUMAN ORGANISMSJolly Okoza, Ph.D. ,Oyaziwo Aluede, Ph.D. and Austin I. Ojugo, Ph.D.Dept. of Educational Foundations and Management,Ambrose Alli University, Ekpoma, NigeriaE-mail address for correspondence :oyaziwoaluede@yahoo.com__________________________________________________________________________________________Abstract : This article explains the formation of human being from a single cell that comes from two biologicalparents as a result of sexual intercourse. The essence of gene in human biological make-up was x-rayed. Growthand development processes from conception to adulthood were discussed. The characteristics that are manifested atthe different stages of physical development and the problems associated with it that are hazardous werehighlighted. The paper recommends that human beings must adopt a good pattern of lifestyle to stay healthy.___________________________________________________________________________________________INTRODUCTIONWe began life as a single cell, a fertilized human egg and developed into a human being made of trillions of cells.The nucleus of each human cell contains 46 chromosomes, which are thread like structures that come in 23 pairs,one member of each coming from each parent (Santrock, 2000). Chromosomes contain the remarkable geneticsubstance known as DNA (Deoxyribonucleic acid), a complex molecule that contains genetic information. DNA isfound in the chromosomes in association with protein, from which it may be separated by chemical methods. It hasmolecular weight of 5 to 10 million and is made up of long chains of nucleotides (Sinnott, Dunn & Dobzhansky,1958).Chromosomes contain thousands of genes. Genes are DNA segments that form templates for the production ofproteins. By directing the manufacture of proteins, the genes determine our individual biological development(Myers, 2004). Our genes, working in complex combinations and together with forces in the environment,ultimately determine many aspects of our biological make up (Baron, 2008). Collectively, some 3.1 billion pairednucleotides define the genes that determine our individual biological development. The sequence of the fournucleotide letters A,T,C and G (Adenine, Thymine, Cytosine and Guanine) – is virtually the same in all humans.Genetically speaking, every human being is close to being your identical twin (Plomin & Crabbe, 2000).Each gene is a self-replicating unit capable of synthesizing proteins the building blocks of our physical development(Myers, 2004). When we speak of development, we mean a pattern of movement or change that begins atconception and continues throughout the life span. This process is attained through heredity. Biological heredity isrealized through a dynamic process of organic development. The union of sex cells at fertilization is followed bytransformation of fertilized egg into an embryo, a fetus an infant, a child, an adolescent, an adult, a senescent andfinally a dead body (Baron, 2008). Consequently, this paper is presented under the following headings:167
<strong>Ozean</strong> Journal of Social Sciences 2(3), 2009i. Physical and sexual development from conception to birth and its associated problemsii. Physical and sexual development from infancy to childhood and its associated problemsiii. Physical and sexual development at adolescence and its associated problemsiv. Physical and sexual development at Adulthood and its associated problems.PHYSICAL AND SEXUAL DEVELOPMENT FROM CONCEPTION TO BIRTH AND ITSASSOCIATED PROBLEMSConception occurs when a single sperm cell from the male penetrates the female’s ovum (egg). This process is alsocalled fertilization. After fertilization, the ovum moves through the mother’s reproductive tract until it reaches thewomb or uterus. This takes several days and during this time the ovum divides frequently. Ten to fourteen daysafter fertilization, it becomes implanted in the wall of the uterus. This fertilized egg is called a zygote. For the nextsix weeks it is known as an embryo and develops rapidly. If, instead, the ovum becomes implanted into the oviduct– the tube connecting the ovary with the uterus – an ectopic pregnancy results. This can be very serious for themother and can cause even death if the condition is undetected; the oviduct can burst as the developing embryogrows larger (Baron, 2008). By the end of the eighth week the embryo is about one inch long, a face as well as armsand legs are present. By this time, too, all major internal organs have begun to form, and some, such as the sexglands, are already active.During the next seven months the developing child now called a fetus shows an increasingly human form. Differentparts of the body grow at different rates during this period. At first, the head grows rapidly compared to the trunkand legs later the lower parts of the body grow more rapidly. The external genitals take shape, so the sex of the fetusis recognizable by the twelfth week. Fingernails and toenails form, hair follicles appear, and eyelids that open andclose emerge. By the end of the twelfth week the fetus is 3 inches (7.6 centimeters) long and weighs about ¾ ounce(21 grams) (Baron, 2008).Under ideal conditions, development during the prenatal period occurs in an orderly fashion and the newborn childis well equipped at birth to survive outside its mother’s body. Unfortunately, however, conditions are not alwaysideal. Many environmental factors can damage the fetus and interfere with normal patterns of growth. The placentatransfers nutrients and oxygen from the mother to fetus, while screening out many potentially harmful substances.But some substances slip by. The placental screen can admit teratogens (Myers, 2004). A teratogen (the wordcomes from the Greek word tera, meaning “monster”) is any agent that causes a birth deficit. We will considersome of the most important teratogens here. During the late 1950s and 1960s, several hundred women tookthalidomide early in pregnancy to prevent morning sickness and insomnia. Tragically, babies born to these mothershad arms and legs that had not developed beyond stumps (Santrock, 2000). Such severely deformed babies with theabsence of limbs or deformed arms and legs are described to suffer a haracteristic known as phocomelia (Clifford,1981).There is no known safe amount of alcohol for a pregnant woman. Even light drinking can affect the fetal brain andeven a single drinking binge can kill millions of fetal brain cells (Braun, 1996; Ikonomidou, Bittagau, Ishimaru,Wozniak, Och, Genz, Price, Stefovska, Hoerster, Tenkova, Dikrania and Olney, 2000). Alcohol enters the Woman’sbloodstream - her fetus – and depresses activity in both their central nervous system. If she drinks heavily, her babywill be at risk of her birth defects and mental retardation. For 1 in 750 infants, the effects are visible as fetal alcoholsyndrome (FAS) (Myers, 2004). This is a cluster of abnormalities that occur in children born by mothers who areheavy drinkers. These abnormalities include a small head (Microencephaly) and defective limbs, face and heart.Most of the children are also below average in intelligence, irritability, hyperactivity, retarded motor and mentaldevelopment, feeding problems and short attention spans (Bokstein, Sampson, Streissgarth & Barr, 1996).Other teragotens for example, rubella or German measles, can cause blindness during the first four weeks ofpregnancy. Other diseases that can be transmitted to the fetus include chicken pox, mumps, tuberculosis, malaria,syphilis and herpes (Samson, 1988). A pregnant woman never smokes alone: she and her fetus both experiencereduced blood oxygen and shot of nicotine. If she is a heavy smoker, her fetus may receive fewer nutrients and beborn underweight. Heavy maternal smoking may also affect fetal brain (Myers, 2004).The importance of woman’s health to the health of their offspring is nowhere exemplified than when the mother isinfected with human immunodeficiency virus (HIV), the virus that is believed to be the cause of acquired immunedeficiency syndrome (AIDS). There are three ways a mother with HIV can infect her offspring:168