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Tuesday, November 23, 2021

Body Growth and Change : ADOLESCENCE

 Body Growth and Change  - ADOLESCENCE:

Puberty : is a period of rapid physical maturation involving hormonal and bodily changes that occur primarily in early adolescence. The features and proportions of the body change as the individual becomes capable of reproducing.

Puberty
 Determinants of Puberty: important physical changes and psychological accompaniments
Period of rapid physical and hormonal changes
Physical changes; growth spurt


Determinants of Puberty:
 important marker for the beginning of adolescence.
There are wide variations in the onset and progression of puberty. 
begin as early as 10 years of age or as late as 13½ for boys. It might end as early as 13 years or as late as 17 years.
Girls – menarche (a girl’s first menstruation), hips widen, body hair. Onset for most: 9 to 15 years of age. 
Boys – first ejaculation, grow taller, body hair.  Onset for most: 10 to 17 years of age.
Precocious puberty is the term used to describe the very early onset and rapid progression of puberty. Onset occurs before 8 years of age in girls and before 9 years of age in boys.
10 times more often in girls than in boys. When it occurs, usually treated with suppressing gonadotropic secretions, which temporarily stops pubertal change. The reasons for this treatment is that children who  have short stature, early sexual capability, and the potential for engaging in age-inappropriate behavior.

The most important factors that influence the onset and sequence of puberty are heredity, hormones, weight, and body fat.

 Heredity:  Programmed into the genes of every human being is a timing for the emergence of puberty. Nonetheless, within the boundaries of about 9 to 16 years of age, environmental factors such as health, weight, and stress can influence the onset and duration of puberty.

Hormones: Hormones are powerful chemical substances secreted by the endocrine glands and carried through the body by the bloodstream. In puberty, the secretion of key hormones is controlled by the interaction of the hypothalamus, the pituitary gland, and the gonads (sex glands). 


Height and Weight in Infancy and Childhood

 Height and Weight in Infancy and Childhood

 Infancy :        Average 20 inches, 7 ½ pounds at birth; 

 Full-term newborns (95%) are 18 to 22 inches long and weigh between 5½ and 10 pounds. 

After delivery lose 5 -7 % body weight. Infants adjust to sucking, swallowing, and digesting, they gaining an average of 5 to 6 ounces per week during the first month. 

They have doubled their birth weight by the age of 4 months.

 1st Year Triple weight by 1 year

  1½ adult height, 20% adult weight by age 2

 2nd Year Rate of growth slows down

Infants weigh approximately 26 to 32 pounds, one-fifth of their adult weight.

32 to 35 inches tall, which is nearly one-half of adult height.

Early   Childhood:   Growth slows, patterns vary individually

Girls slightly smaller and lighter than boys.

Both boys and girls slim down

Heads are large for their bodies, by the end of the preschool years they have lost their top-heavy look.

Girls gain fat, boys gain muscle.

Height differences are based on the ethnic origin and nutrition.

SES: First born --taller --Urban & Middle

Mothers smoked during pregnancy were half an inch shorter

Problems for short:

Congenital factors (genetic or prenatal problems), growth hormone deficiency, a physical problem that develops in childhood, or an emotional difficulty. 

Physical problems include malnutrition and chronic infections.

Middle and Late Childhood:  6 - 11 yrs; Slower, consistent growth
Elementary school years - grow an average of 2 to 3 inches a year. 
Boys & Girls 4 feet 2 inches tall and gain about 5 to 7 pounds a year. 8 yrs weigh 56 pounds. 
Muscle mass and strength increase as well as the size of some body organs.
increase in muscular strength is due to heredity and exercise.
Boys stronger, body proportions change
Head circumference, waist circumference, and leg length decrease in relation to body height.












Physical Development and Health: Body Growth and Changes (Growth Pattern)

 Physical Development  and Health


Body Growth and Changes: Growth Pattern

Patterns of growth (Infancy and Childhood, Puberty)


Changes in Proportions of  the Human Body During Growth

During prenatal development and early infancy, the head constitutes an extraordinarily large portion of the total body,  it generally follows two patterns: the cephalocaudal pattern and the proximodistal pattern.

Cephalocaudal pattern – from top (head) and  gradual to bottom (The sequence in which the fastest growth occurs at the top of the body—the head—with physical growth in size, weight, and feature differentiation gradually working from top to bottom). Eg. from neck to shoulders, to middle trunk, and so on .  

Sensory and motor development also generally proceed.

Proximodistal pattern – center of body outward  to extremities. (The sequence in which growth starts at the center of the body and moves toward the extremities) Eg, muscle control of the truck and arms matures

Growth rate affected by SES, birth order, and  maternal habits during prenatal development  ---Growth hormone deficiency – pituitary gland


Monday, August 9, 2021

Periods of development

 Periods of development:

Prenatal period: from conception to birth

Infancy and toddlerhood: birth to 2 years

Early childhood: 2-6 years old

Adolescence: 12-19 years old

Middle & late childhood: 6-12 years old

Early Adulthood: begins in the begins in the late teens or early twenties and lasts through the thirties.

Middle Adulthood: from 40 years of age to about 60. 


Late Adulthood: begins in the sixties or seventies and lasts until death. - the young old, or old age, and the old old, or late old age.

Prenatal period:  from conception to birth. It involves tremendous growth—from a single cell to an organism complete with brain and behavioral capabilities, produced in approximately a nine-month period.

Infancy:  from birth to 18 or 24 months. It is a time of extreme dependence upon adults. Many psychological activities are just beginning—language, symbolic thought, sensorimotor coordination, and social learning, for example.

Early childhood: from the end of infancy to about 5 or 6 years. It sometimes called the “preschool years.” During this time, children learn to become more self-sufficient and to care for themselves, develop school readiness skills (following instructions, identifying letters), and spend many hours in play with peers. First grade typically marks the end of early childhood.

Middle and late childhood:  from about 6 to 11 years of age. It is called as the “elementary school years.” The fundamental skills of reading, writing, and arithmetic are mastered. The child is formally exposed to the larger world and its culture. Achievement becomes a more central theme of the child’s world, and self-control increases.

Adolescence : period of transition from childhood to early adulthood, entered at 10 to 12 years of age and ending at 18 to 22 years of age. A rapid physical changes begins—dramatic gains in height and weight, changes in body contour, and the development of sexual characteristics such as enlargement of the breasts, development of pubic and facial hair, and deepening of the voice. At this point pursuit of independence and an identity are prominent. Thought is more logical, abstract, and idealistic. More time is spent outside the family.

Early adulthood: begins in the late teens or early twenties and lasts through the thirties. It is a time of establishing personal and economic independence, career development, and, for many, selecting a mate, learning to live with someone in an intimate way, starting a family, and rearing children.

Middle adulthood: from 40 years of age to about 60. It is a time of expanding personal and social involvement and responsibility; of assisting the next generation in becoming competent, mature individuals; and of reaching and maintaining satisfaction in a career.

Late adulthood: begins in the sixties or seventies and lasts until death. It is a time of adjustment to decreasing strength and health, life review, retirement, and adjustment to new social roles.

Life-span developmentalists increasingly distinguish between two age groups in late adulthood: the young old, or old age, and the old old, or late old age. Still others distinguish the oldest old (85 years and older) from younger older adults.

The Young Old (65 to 84)

:Increase their life expectancy with more older adults living longer

Have considerable potential for improved physical and cognitive fitness

Retain much of their cognitive capacity

Can develop strategies to cope with the gains and losses of aging

.The Oldest Old (85 and older): 

Show considerable loss in cognitive skills

Experience an increase in chronic stress

Alzheimer disease more common and individuals more frail

Dying with dignity less likely

.


Domains of Development

 Domains of Development

Development is described in three domains, but growth in one domain influences the other domains.

Physical Domain: 

body size, body proportions, appearance, brain development, motor development, perception capacities, physical health.

Cognitive Domain:

thought processes and intellectual abilities including attention, memory, problem solving, imagination, creativity, academic and everyday knowledge, metacognition, and language.

Social/Emotional Domain:

self-knowledge (self-esteem, metacognition, sexual identity, ethnic identity), moral reasoning, understanding and expression of emotions, self-regulation, temperament, understanding others, interpersonal skills, and friendships.


Early and Late Maturation

 Early and Late Maturation:

When adolescents mature earlier or later than their peers, they often perceive themselves differently and their maturational timing is linked to their socioemotional development and whether they develop problems.

 In the Berkeley Longitudinal Study, early-maturing boys perceived themselves more positively and had more successful peer relations than did latematuring boys.

 The findings for early-maturing girls were similar but not as strong as for boys.

When the late-maturing boys were in their thirties, they had developed a more positive identity than the earlymaturing boys had.

Perhaps the late-maturing boys had more time to explore life’s options, the early-maturing boys continued to focus on their physical status instead of paying attention to career development and achievement.

 The early maturation increases girls’ vulnerability to a number of problems.

Early-maturing girls are more likely to smoke, drink, be depressed,  have an eating disorder, struggle for earlier independence from their parents, and have older friends; and their bodies are likely to elicit responses from males that lead to earlier dating and earlier sexual experiences.

 Recent study revealed that early-maturing girls were more likely to try cigarettes and alcohol without their parents’ knowledge.

--are less likely to graduate from high school and tend to cohabit and marry earlier.

--social and cognitive immaturity, combined with early physical development, early-maturing girls are easily lured into problem behaviors, not recognizing the possible long-term effects of these on their development. 

ADOLESCENCE Determinants of Puberty

 ADOLESCENCE

Puberty is a period of rapid physical maturation involving hormonal and bodily changes that occur primarily in early adolescence.

The features and proportions of the body change as the individual becomes capable of reproducing.

 Determinants of Puberty:

Puberty is not the same as adolescence.

--as the most important marker for the beginning of adolescence.

 Puberty might begin as early as 10 years of age or as late as 13½ for boys.

It might end as early as 13 years or as late as 17 years.

 In fact, over the years the timing of puberty has changed.

For example, in Norway, menarche—a girl’s first menstruation—now occurs at just over 13 years of age, compared with 17 years of age in the 1840s.

 United States, where children mature up to a year earlier than in European countries.

 The normal range for the onset and progression of puberty for Girls occurs between the ages of 9 and 15.

 Precocious puberty is the term used to describe the very early onset and rapid progression of puberty.

 Judith Blakemore and her colleagues (2009) recently described the following characteristics of precocious puberty:

--pubertal onset occurs before 8 years of age in girls and before 9 years of age in boys.

--10 times more often in girls than in boys.

 It usually is treated by medically suppressing gonadotropic secretions, which temporarily stops pubertal change.

 The reasons for this treatment is that children who experience precocious puberty are ultimately likely to have short stature, early sexual capability, and the potential for engaging in age-inappropriate behavior.

Among the most important factors that influence the onset and sequence of puberty are heredity, hormones, weight, and body fat.

1. Heredity --Puberty is not an environmental accident. It does not take place at 2 or 3 years of age, and it does not occur in the twenties.

Programmed into the genes of every human being.

2. Hormones-- Behind the first whisker in boys and the widening of hips in girls is a flood of hormones.

Hormones are powerful chemical substances secreted by the endocrine glands and carried through the body by the bloodstream.

 It is controlled by the interaction of the

 The hypothalamus is a structure in the brain best known for hypothalamus, the pituitary gland, and the gonads (sex glands). -- monitoring eating, drinking, and sex.

 The pituitary gland is an important endocrine gland that controls growth and regulates other glands.

 The gonads are the sex glands—the testes in males, the ovaries in females.

 The key hormonal changes involve two classes of hormones  

--in males and females are: Androgens and Estrogens.

 Testosterone is an androgen that is a key hormone in the development of puberty in boys.

As the testosterone level rises during puberty, external genitals enlarge, height increases, and the voice changes.

 

Estradiol is an estrogen that plays an important role in female pubertal development.

As the estradiol level rises, breast development, uterine development, and skeletal changes occur.

 Are there links between hormones and adolescent behavior? Findings are inconsistent.

For example, one study found that social factors accounted for two to four times as hormonal factors in young adolescent girls’ depression and anger.

 Hormones do not act independently; hormonal activity is influenced by many environmental factors,

including parentadolescent relationships.

 Stress, eating patterns, sexual activity, and depression can also activate or suppress various aspects of

the hormone system.

 Growth Spurt: The rapid increases in growth since infancy.

The growth spurt associated with puberty occurs approximately two years earlier for girls than for boys.

(9 years of age for girls and 11 years of age for boys -USA).

 Boys and girls who are shorter or taller than their peers at the beginning of adolescence, girls are taller than boys, but later years most boys have taller than girls.

 

Sexual Maturation:

FOR BOYS: increase in penis and testicle size, appearance of straight pubic hair, minor voice change, first ejaculation (which usually occurs through masturbation or a wet dream), appearance of pubic hair, onset of maximum body growth, growth of hair in armpits, more detectable voice changes, and growth of facial hair.

 Three of the most noticeable areas of sexual maturation in boys are penis elongation, testes development, and growth of facial hair.

 FOR GIRLS:  First, on average the breasts enlarge and then pubic hair appears.

---the female grows in height, and her hips become wider than her shoulders.

Her first menstruation (menarche) occurs rather late in the pubertal cycle; it is considered normal if it occurs between the ages of 9 and 15.

 Pubertal females do not experience voice changes comparable to those in pubertal males.

By the end of puberty, the female’s breasts have become more fully rounded.

 

Body Image:

One psychological aspect of physical change in puberty is certain: Adolescents are preoccupied with their bodies and develop images of what their bodies are like.

 Preoccupation with body image is strong throughout adolescence and dissatisfied with their bodies than in late adolescence.

 Gender differences characterize adolescents’ perceptions of their bodies.

In general, girls are less happy with their bodies and have more negative body images than boys throughout puberty.

 As pubertal change proceeds, girls often become more dissatisfied with their bodies, probably because their body fat increases.

In contrast, boys become more satisfied as they move through puberty, probably because their muscle mass increases.

 Also some variations, keep in mind that there is considerable variation, with many adolescent girls having positive body images and many adolescent boys having negative body images.