Introduction to Human Development Essay Example

Introduction to Human Development Essay INTRODUCTION â€Å"The human being†¦ the most sophisticated, amazing and wondrous creation in this earth. If one would take a peek at what’s inside his human body, he’ll be amazed to see hundreds of bones, miles of blood vessels and trillions of cells, all working together so he could be healthy and in perfect shape. Each organ, each body part, each a miracle†¦ Each a piece of evidence of God’s mighty providence. † This lesson familiarizes you with the principles and stages of human growth, maturation and development. It discusses how humans grow, develop, change and adapt to their environment throughout their life span. Warm-Up Did you know that there are 26 billion cells in a new born baby and about 50 trillion cells in an adult? Cells are responsible for supplying you with the energy you need, transporting oxygen around your body and moving your body parts. Indeed, every single cell in your body helps you maintain vitality and life. BASIC CONCEPTS 1. Human Development refers to the biological and psychological development of the human being throughout the lifespan. It consists of the development from infancy, childhood, and adolescence, adulthood to old age. . Development refers to the qualitative, progressive series of changes in an orderly and coherent fashion leading to maturation 3. Growth refers to quantitative changes in an individual as he progresses in chronological age. 4. Maturation is the process by which heredity exerts its influence long after birth. 5. Genetics is the science of heredity. It originated with the discovery by Gregor Mendel that hereditary characters are determined by f actors transmitted without change and in predictable fashion from one generation to the next. 6. We will write a custom essay sample on Introduction to Human Development specifically for you for only $16.38 $13.9/page Order now We will write a custom essay sample on Introduction to Human Development specifically for you FOR ONLY $16.38 $13.9/page Hire Writer We will write a custom essay sample on Introduction to Human Development specifically for you FOR ONLY $16.38 $13.9/page Hire Writer Heredity is the passing on of physical or mental characteristics from parents to offspring through the genes. 7. Gene is a unit of heredity; a segment of the DNA which contains the instructions for the development of a particular inherited characteristic. There are about 30,000 genes that contain chemical instructions. The chemical instructions in the genes program the development of millions of individual parts into a complex body and brain. 8. DNA or deoxyribonucleic acid is a nucleic acid which occurs in combination with protein in the chromosomes, which contains the genetic instructions. It consists of four nitrogenous bases (adenine, guanine, thymine, cytosine), a sugar (2-deoxy-D- ribose), and phosphoric acid, arranged in a regular structure- (two chains twisted round each other in the form of a double helix). 9. Nucleic acids are large molecules produced by living cells which store genetic information, and composed of a chain of nucleotides. Two forms are: deoxyribonucleic acid (DNA) which is found primarily in the nucleus and ribonucleic acid (RNA), found in the nucleus and cytoplasm. 10. Chromosomes are threads within the nucleus of a cell which are the carriers of genetic material, consisting of DNA and various types of protein (histones). They occur in pairs a normal human body cell has 46 chromosomes: 22 pairs of autosomes together with one matching pair of X chromosomes in females (the 23rd pair- XX) and one mismatching pair, the X and Y sex chromosomes in males (the 23rd pair-XY) 11. Sex chromosome is the 23rd pair of chromosomes represented differently in the sexes, and responsible for the genetic determination of the sex of an individual. There are 1,000 genes in each chromosome. 12. Gamete is a specialized reproductive cell that fuses with another gamete of the opposite sex during fertilization, to form a zygote. Gametes are usually differentiated into male (sperm) and female (egg, ovum). 13. Sexual Reproduction is the act or process of producing offspring through sexual intercourse or artificial insemination. The Stages of Reproduction: 1. During ovulation period, females release and deposit sex chromosomes in the uterus. In the reproduction process, the male releases sperm cells that contain either X or Y chromosomes. The first male chromosome that meets and unites with the egg determines the gender of the offspring. If Y chromosome from the male first unites with the egg (which is an X chromosome), the offspring is male (XY). But if an X chromosome coming from the male first unites (XX), the gender of the offspring is female. 2. The successful sperm cell penetrates inside the ovum. The tail of the sperm separates to the head during this process. The nucleus of the sperm cell will then unite with the nucleus of the ovum and undergo a process called fertilization. The 23 chromosomes from the sperm cell will pair with the 23 chromosomes from the egg cell and the resulting zygote starts life with 46 chromosomes. . When the zygote is about to divide, chromosome replication and cell division arise wherein chromosomes and genes are doubled. All cells except the reproductive cells receive identical inheritance. The process of cell division continues with the chromosomes being always replicated as described. 4. Sometimes, instead of remaining together as parts of a single organism, the cells separate. Th ey develop to form identical twins. Siamese twins come from an incomplete separation of the two identical cells. 5. However, if two egg cells are fertilized separately, they develop to form fraternal twins. Chromosomal Abnormalities: 1. Turner’s syndrome- is a rare case wherein females may be born with only 1 X chromosome (45 chromosomes instead of 46). They fail to develop sexually at puberty. They show normal intelligence but with cognitive defects like poor performance in math and spatial organization. 2. Down’s Syndrome- a defect which usually stems from a failure of one chromosome of a germ cell to split in the normal way to form a healthy ovum with 23 chromosomes; an ovum with 24 chromosomes is produced, and if this ovum is fertilized, the developing embryo possesses an extra chromosome (47). The condition is named after English physician J L H Down (1828-96), and is sometimes referred to as mongolism. 3. Klinefelter’s Syndrome- a rare case wherein the 23rd chromosome fails to divide properly giving off extra X or Y chromosome (47). An individual with an xxy 23rd chromosome is physically a male but with feminine characteristics like large breasts but with small testes incapable of producing sperms. Male with XYY chromosomes are taller and unusually aggressive than the normal XY. Sex-Linked Genes 1. Sex-Linked Genes bare genes carried on the X and Y chromosomes, and the characteristics they control. In mammals females have two X chromosomes and males an X and a Y chromosome. Women transmit one X chromosome to either sons or daughters, while men pass their X chromosome only to their daughters. a. A characteristic feature of sex-linked inheritance is thus the absence of male-to-male transmission. Most sex-linked diseases in humans are inherited as recessives; with the males the affected sex (e. g. colorblindness, baldness, hemophilia, Duchenne muscular dystrophy). 2. Hemophilia is an inherited disorder of blood coagulation, resulting from a deficiency in one of the proteins responsible for normal blood clotting. STAGES OF HUMAN DEVELOPMENT STAGESAGEHIGHLIGHTS 1. Prenatal Conception to birth Rapid physical development of body and nervous system 2. Infancy Birth to 2 years Motor development. Attachment to primary caregiver. 3. Childhood 2 to 12 years Increasing ability to think logically and reason abstractly. Refinement of motor skills. Peer socialization. 4. Adolescence 13 to 20 years Thinking and reasoning are more mature like. Identity crisis. Socializations to opposite sex. STAGESAGEHIGHLIGHTS 5. Adulthood 21 to 60 years Love, marriage, career and stability. . Old Age 61 to retirement Reflection of accomplishments. Physical and mental health deteriorates. A. Prenatal Stage 1. Prenatal Period- the period from conception to birth, usually encompassing nine months of pregnancy. 2. Pregnancy is a physiological process in which females nurture their developing young within the uterus; also known as gestation. It begins when the fertilized ovum embeds itself in the uterine wall (implantation), and ends with the birth of the offspring (parturition). It lasts on average 38 weeks (9 ? onths or 266 days) from the first day of the last menstrual period, menstruation is absent (in response to circulating hormones), the uterus enlarges, the breasts increase in size in preparation for lactation, and there are other major physiological changes. 3. Fertilization is the union of two gametes to form a zygote, as occurs during sexual reproduction. 4. Zygote a one-celled organism formed by the union of a sperm and egg cell. The zygote undergoes rapid mitotic divisions with no significant growth (a process known as cleavage) and cellular differentiation, leading to development of an embryo. . Cleavage is the process by which a fertilized egg cell (zygote) divides to give rise to all the cells of an organism. The prenatal stages 1. Germinal stage the first prenatal stage that occurs from first to second week of conception. 2. Embryonic stage the second prenatal stage that occurs fr om third to eighth week of conception. 3. Fetal stage the third and final prenatal stage that occurs from ninth week of conception to birth. STAGE AGE (week) SIZE CHARACTERISTICS GERMINAL STAGE or period of zygote (1 to 2 weeks) 1 week 150 cells Zygote attaches to the uterine lining. weeksSeveral thousand cellsPlacental circulation established EMBRYONIC STAGE or period of embryo (3 to 8 weeks)3 weeks1/10 inchMajor systems, organs, and structures of the body develop. 6 weeks? inchArms and legs develop. Jaws form around mouth. 8 weeks1 inch, 1/30 ounceBones begin to develop in limbs. Sex organs begin to form. FETAL STAGE or period of fetus (9 weeks to birth)9 (2. 5 mos. )1 ? inchFormation of brain; Gender can be distinguished. 12 (3 mos. )3 inches, 1 ounceCan smile and frown; Circulatory system working. 16 (4 mos. )6. 5 inches, 4 ounceHeartbeat is strong; Mother feels movement. 0 (5 mos. )10 inches, 5 ounceHiccups begin; hair form 24 (6 mos. )12 inches, 1. 5 lbsVisual and auditory se nses functional; eyes open. 28 (7 mos. )15 inches, 2. 5 lbsBody fat is added; brain specialization. 32 (8 mos. )17 inches, 2. 5 lbsPeriods of sleep and wakefulness. 36 (9 mos. )19 inches, 6 lbsRapid increase in weight; Gains immunity from mother. 38 (9 1/5)21 inches, 8 lbsBirth- 266 days from conception. B. INFANCY. 1. Infancy is the period of human development from birth to two years. 2. Neonate is a newborn child. 3. Capacities of a newborn: a. Newborns have poor vision and cannot see as well as an adult until about age 2. b. Newborns pay attention to sounds particularly to human speech. c. Infants can discriminate different tastes and prefer sweets like breast milk. d. Neonate can identify odors especially that of the mother. e. Infants can learn from the moment they are born and show good memories by 3 months of age. 4. Motor Development refers to the progression of muscular coordination required for physical activities. Stages of Motor Development In Infancy AGE (months)ACTIVITIESAGE (months)ACTIVITIES Lifts head up 11 Stands alone 2. 5 Rolls over 12 Walks alone 3 Sits propped up 14 (1 yr, 2 mos) Walks backward 6 Sits without support 17 (1 yr, 5 mos) Walks up steps 6. 5 Stands holding on 20 (1 yr, 8 mos) Kicks ball forward 9 Walks holding on 10 Stands momentarily 5. Critical Periods are the crucial time periods in a person’s life during which specific events occur if development is to proceed normally. In fetus, t he 6 to 7 weeks is critical for normal development of the sex organs- like deficiency in hormones. Visual corrections are critical up to 7 years old. . Sensitive Periods are periods that are optimal for a particular kind of development. First year of life is a sensitive period for interpersonal attachment. 7. Temperament refers to such mood-related personality characteristics. a. Easy Temperament is a term used to describe a child who is playful, regular in his sleeping and eating patterns, and adapts readily to new situations. b. Difficult Temperament is a term used to describe a child who is irritable, has irregular sleeping and eating patterns, and responds intensely and negatively to new situations. c. Slow to warm up temperament is a term used to describe a child who is relatively inactive, tends to withdraw from new situations in a mild way, and requires more time than easy infants to new situations. 8. Attachment is used to describe an infant’s tendency to seek closeness to particular people (especially the mother) and to feel more secure in their presence. 9. Separation anxiety is a distress among infants when a caretaker is not nearby. 10. Sensitive Responsiveness is a characteristic of a caretaker who responds promptly when the baby cries and behaves affectionately when they pick up the baby. The caretaker also tailors their response to the baby’s needs. C. ADOLESCENCE 1. Adolescence refers to the period of transition from childhood to adulthood covering 13 to 20 years old. It is characterize by a rapid physical growth known as the adolescent growth spurt. 2. Puberty is a period of sexual maturation that transforms a child into a biologically mature adult capable of sexual reproduction, which takes place over a period of 3 or 4 years. a. It starts when a female has a menarche between the ages of 11 to 17 (average is 12) and when a male begin to ejaculate semen between the ages of 12 to 16 (average is 14 1/2). . Secondary sex characteristics like bodily hair patterns, pitch of voice and muscle development are evident for both males and females. c. Changes in the intellectual abilities, body proportions, and sexual urges (together with changing relationships with parents and peers) create enormous challenges. d. Psychological effects of puberty such as moodiness, inn er turmoil, and rebellion are linked directly to the hormonal changes of puberty. D. ADULTHOOD 1. Adulthood is a stage of human development from ages 21 to 60 that is marked by both maturity and change. . It involves transition in the family relationships, including adjusting to marriage parenthood and empty nest. 2. Age-related physical transitions include: changes in appearance; sensory losses (especially vision and hearing), and hormonal changes. Mental speed declines. a. Menopause is the cessation of menstruation that usually occurs between 45 and 50 years. It is often accompanied by physical (sweating, hot flushes, vaginitis) and psychogenic (depression, insomnia, fatigue) disturbances, which generally respond to estrogen therapy. . Mid-life Crisis is a difficult, turbulent period of doubts and reappraisal of one’s life. E. OLD AGE 1. Old age a stage of human development which covers those 65 years old and above. 2. Ageism is discrimination on the basis of age, often res ulting in the denial of rights and services in the elderly. a. Dementia- is a brain disorder that involves losses of cognitive abilities and mental functioning. b. Alzheimer’s disease is a degenerative disorder whose progression cannot be stopped; it is irreversible and ultimately ends in death.