Psychology Chapter 5 Girls Encouraged Less Tomboyish And More Sedentary

Chapter 5

5

BODY, BRAIN, AND HEALTH

LEARNING OBJECTIVES

After reading and studying the material in this chapter, the student should be able to

understand the following ideas/concepts.

5.1 BUILDING BLOCKS OF GROWTH AND LIFELONG HEALTH

• Associate key processes of the endocrine and nervous systems with important aspects of

5.2 THE INFANT

• Discuss typical changes in the brain during infancy.

5.3 THE CHILD

5.4 THE ADOLESCENT

5.5 THE ADULT

• Integrate the findings of both gains and losses in the adult brain.

• Summarize changes in the reproductive system throughout adulthood, with attention to

Chapter 5

CHAPTER OUTLINE

I Building Blocks of Growth and Lifelong Health

A. Growth and a Related Disorder

1. Human growth is a complex process that occurs over many years and is

influenced by genetic and environmental factors

a. Average U.S. female: 5’ 4”; average U.S. male: 5’ 10”; but great variability

B. The Endocrine System

1. Endocrine glands secrete chemicals called hormones into bloodstream

2. Pituitary gland – “master” endocrine gland located at base of brain

a. Directly controlled by hypothalamus

b. Triggers release of hormones from all other glands and produces growth

3. Thyroid gland plays key role in growth and development and impact on nervous

system

a. Unnoticed deficiency of gland can lead to lower IQ in infants and slower

4. Males and sex hormones

a. Male fetus will not develop testes (a type of endocrine gland) unless gene on

Y chromosome triggered

5. Ovaries – female endocrine glands that produce larger quantities of the primary

female hormone estrogen and of progesterone

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6. Adrenal gland secretes hormones that contribute to maturation of bones and

muscles in both sexes

7. In adulthood, endocrine glands continue to regulate bodily processes

C. The Brain and Nervous System

1. The nervous system components – brain, spinal cord, and neural tissue

2. Neuron – basic cell unit of nervous system

a. Dendrites – branches that receive signals from other neurons

b. Axon – long segment of neuron in which signal is transmitted

c. Synapse – gap between neurons

d. Neurotransmitter – brain chemicals stored at end of the axons released across

D. Principles of Growth

1. Cephalocaudal principle – head to tail development

a. Head growth first, then trunk, then legs

2. Proximodistal principle – center outward to extremities

3. Orthogenetic principle – global and undifferentiated to increased differentiation

and hierarchical integration

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1. Health is a life-long process (influenced by personal choice)

Checking Mastery

1. How does the endocrine system support development?

➢ Answer: The endocrine system consists of a set of glands that secrete chemicals

called hormones directly into the bloodstream. One of these is the pituitary gland,

2. How does myelination contribute to developmental changes that we can observe?

➢ Answer: Myelination speeds up neural “communication” and proceeds in a

3. What is one example each of cephalocaudal and proximodistal development?

➢ Answer: An example of cephalocaudal (head to tail) growth is that the head is

II The Infant

A. Rapid Growth

1. Typical newborn 20 inches and 7-7.5 pounds

2. Early size related to prenatal experience

a. Ounce per day and inch per month gain

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i. Grasping reflex may help infants cling to caregivers

3. Behavioral states – organized, individual patterns of daily activity

a. Predictable sleep-wake cycles within six months after birth

i. Newborns spend half of time in active, rapid eye movement (REM) sleep

deprivation)

C. Health and Wellness

1. Most babies under 750 grams (1 lb, 10.5 ounces) die within first year

2. Complications of premature birth second leading cause of death during first year

3. Congenital malformations – genetic or prenatal event defects present at birth

Checking Mastery

1. What are the most significant brain changes that occur during infancy?

➢ Answer: The young brain undergoes synaptogenesis, or growth of synapses

2. What are two infant reflexes that may help ensure survival in the early months of life?

3. What can an infant’s sleep-wake cycle indicate about her development?

➢ Answer: Establishing a regular sleep-wake cycle can show that infants are

III The Child

A. Steady Growth

a. Steady but slower (ages two through puberty) – 2 to 3 inches and 5 to 6

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B. Brain Laterization

C. Physical Behavior

1. Unlike infants, children master ability to move in a changing environment

(adaptation)

2. Refinement of motor skills (initially awkward)

a. Can run in a straight line

3. Improvements in eye/hand coordination often due to practice

a. Age three, have hard time with buttons

4. Faster reaction times steady improvement across childhood

a. Increased speed of neural processing leads to improvements in memory and

other cognitive functions

D. Health and Wellness

1. Many factors impact health (e.g., parent’s education, socioeconomic status)

2. Socio-historical context also plays role in the health and well-being of a child

4. Nutrition important contributor to childhood health

a. As appetite diminishes, children may become picky eaters

b. Fast foods are often high in carbohydrates and low in nutrition

i. School children often frequent convenience stores and consume many

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5. Schools can have big impact

a. Students in schools with breakfast programs have healthier weights as

indicated by body mass index (BMI)—marker of body fat calculated from

6. Physical activity fosters good health

a. Children need 60 minutes of moderate or vigorous exercise a day

b. Physical fitness may enhance cognitive functioning (including academic

7. Increasing number of children meet criteria for obesity—being 20% or more

above ideal weight for height, age, and sex

i. Obesity rates have tripled in past 30 years

ii. Children in neighborhoods with safe outdoor activities less likely to be

Checking Mastery

1. How are brain functions of the two hemispheres typically organized?

➢ Answer: Activity within the two hemispheres of the brain is typically

2. What are two major factors that contribute to health during childhood?

3. What are two things that schools or parents can do to influence children’s eating

behaviors in order to help them maintain or achieve a healthy weight?

IV The Adolescent

A. The Adolescent Brain: What’s Going on in There?

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1. Many brain changes during adolescence

a. Volume of gray matter increases, peaks, then decreases

B. The Growth Spurt

2. Adolescent growth spurt

a. Triggered by hormones

b. Boys and girls grow at different rates

i. Female peak growth for height around age 12, male peak age 13.4

ii. Female peak weight growth around age 12.5, male peak age 13.9

C. Sexual Maturation

1. Sexual maturation due to adrenal gland activity and release of adrenal androgens

(called adrenarche) and gonadal hormones

a. Adrenarche primarily responsible for secondary sex characteristics (e.g., pubic

2. Tanner scale used to measure progression through puberty and attainment of

sexual maturity

a. Five stages ranging from prepubertal—no evidence of secondary sexual

characteristics— to adult secondary sexual characteristics

b. Females

i. Menarche – first menstruation

3. Variations in timing

a. Genes help determine the rate of adolescent development

b. Physical and sexual maturation triggered when hypothalamus of brain

stimulates endocrine system

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i. Boys and girls have similar levels of “male” and “female” hormones

c. Secular trend – earlier maturation and greater body size in industrial societies

i. Better medical care and nutrition

d. Stress may delay sexual maturation

4. Family situations affect timing of puberty

a. Girls of depressed mothers tend to enter puberty earlier

b. Girls in homes involving separation or divorce tend to enter puberty earlier

D. Psychological Implications

1. Concern with body image

a. Concern more prominent in females, with individual reactions varying widely

b. Negative cultural views of menstruation lead to negative image

c. Boys have more positive body images

i. Welcome change in height and weight and related to athletic prowess

ii. Constitutional growth delay – characterized as being at or below fifth

iv. Relationships tend to become warmer after puberty

E. Early vs. Late Development

1. Early maturation more advantageous for boys than for girls

a. Early maturing boys

i. More positive effects including social competence and self-assuredness

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c. Early maturing girls

i. Do not tend to gain status from increase in size (as boys do) and may be

the subject of ridicule

ii. Higher levels of body dissatisfaction

d. Late maturation for girls

i. Some anxiety but not as disadvantageous as for boys

ii. Outperform others on school achievement tests

2. Impact of time of maturity tends to fade with time

a. May be some risk of long-term problems associated with early maturing girls

3. Psychological differences between late and early maturation becoming smaller

a. Timing-of-puberty effect mediated by adolescent’s perceptions

i. Self-perception for reason of timing (“late bloomer” vs. athletic impact)

F. Physical Behavior

1. Muscular strength and physical competence increases (e.g., ball throwing,

jumping)

2. Many adolescents not as active as they should be

G. Health and Wellness

1. Sedentary lifestyle of modern society undermining physical fitness of teens

a. Adolescents drinking more nutrient-poor beverages gain weight and have

higher systolic blood pressure, which increases risk for later health problems

(e.g., kidney disease, arthritis)

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2. Unintentional injuries leading cause of death in teens

a. Mostly vehicle accidents

Checking Mastery

1. How do the typical brain changes throughout adolescence correlate with teen

behavior?

➢ Answer: A heightened period of synaptogenesis and pruning seems to occur at

2. Which group of teens is likely to have the “best” experience of puberty and which

group is likely to experience more problems with the process of puberty?

➢ Answer: Experience with the process of puberty will be influenced by many

3. What factors affect timing of menarche in girls?

➢ Answer: Timing of menarche is influenced by genetic factors, body weight (in

V The Adult

A. Typical Changes

B. Appearance and Physical Functioning

1. Most changes after 40

a. Wrinkles, graying and thinning hair, and weight gain

b. “Middle–age spread” controllable by exercise, but adults often do not have the

time

i. Just 30% of adults engage in any physical activity during leisure time

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e. Aging involves gradual decline in efficiencies of body systems in later life

i. Loss of heart and lung capacity

ii. Loss of muscle strength

iii. Decrease in ability to control body temperature and of immune system to

fight disease

2. Decrease in reserve capacity—ability of organs to respond to demand, lower

maximal heart rate—is a fact of aging

a. Older age decline related to decreased involvement in vigorous physical

activities

C. Psychological Implications

a. Negative stereotypes can lead to “ageism”—prejudice against elderly

i. Some older adults bothered by physical appearance (women more so than

D. The Changing Brain

1. Brain development is never truly complete

2. Normal aging includes only mild nervous system degeneration

a. Brain weight and volume decrease in adult years

3. The brighter side

4. Scaffolding Theory of Aging and Compensation (STAC)

E. The Changing Reproductive System

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1. Sex hormone levels fluctuate in both males and females

a. Males fluctuate more annually

i. High levels of testosterone related to aggression and sexual activity, but

changes in hormone levels not clearly tied to changes in mood or behavior

2. Female menopause

a. Menopause – ending of menstrual period in midlife (i.e., no ovulation or

menstruation)

i. Typical age range is from 45 to 54; due to drop in levels of estrogen and

other female hormones creating a hormone mix more “masculine” and less

“feminine” than that of premenopausal women

ii. Age of menopause somewhat related to when a woman’s mother reached

menopause

viii. Expectation of impact also predict reaction

b. Hormone replacement therapy or HRT—replacement of estrogen/progestin—

was thought to compensate for loss of hormones

i. HRT often relieves physical symptoms of menopause (e.g., hot flashes,

vaginal dryness)

3. Male andropause

a. Andropause – male loss of reproductive capacity (“male menopause”)

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F. Slowing Down

1. Older adults tend to perform motor actions more slowly and with less

coordination

a. Most trouble on novel and complex tasks

b. Slowing is the result of slowing of brain and nervous system affecting motor

iii. Aerobic exercise and playing video games can increase speed of reactions

G. Disease, Disuse, and Abuse

1. Effects of aging confounded with effects of disease, disuse, or abuse

2. Most older people have some chronic disease (e.g., arthritis, heart disease)

a. Birren (1963) found one group of older men with no sign of disease compared

with others with slight traces, but no clinically diagnosable diseases

i. Healthier group of older men hardly differed from younger men

b. Disuse contributes to steep declines in physical functioning (“use it or lose it”

maxim)

i. Body disuse (sedentary lifestyle) will result in muscle atrophy

H. Health and Wellness

1. Many 70-and-older adults have at least one chronic impairment

a. About half have arthritis or hypertension (high blood pressure)

2. Exercise very important to staying healthy

a. Low-intensity exercise and weight lifting can increase strength

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3. Osteoporosis – disease resulting in loss of bone mass due to loss of minerals,

leaving bones more fragile and easier to fracture

a. Nearly one-third of older adults with hip fracture die within one year

4. Osteoarthritis – aging of the joints due to use that damages the cartilage resulting

in pain and restricted movement

I. Theories of Aging: Why Do We Age and Die?

a. Maximum Life Span

J. Successful Aging

1. Snowdon (2002) longitudinal study of nuns

a. Underwent annual mental and physical testing

b. Nuns with autobiographies with positive emotions lived longer

Checking Mastery

1. What physical changes, including those in the brain, can we expect as we age?

➢ Answer: With old age come some physical changes, including slowing down of

2. What is the major difference between a programmed theory of aging and an error

theory of aging?

➢ Answer: Programmed theories of aging emphasize predictable, genetically-based

3. What have we learned about successful aging from the “Nun Study” and other

research on centenarians?

➢ Answer: From the “Nun” Study, we know there is a connection between level of

Chapter 5

SUGGESTIONS FOR CLASS DISCUSSIONS OR PROJECTS: To develop critical thinking

skills and enhance learning with exercises that support the course learning objectives.

1. Physical Characteristics across the Life Span: Ask students to report on the media’s portrayal

of physical characteristics across the lifespan. For example, students might:

• Look through magazine articles and advertisements to determine the following: Are older

2. Developmental Drawings: Bring into class, or have the class collect, drawing samples from

children of various ages. These can also be used to show children’s early attempts at mastering

3. Nutrition and Development: A number of sources have pointed to school lunches as a major

contributor to the increased incidence of obesity in school children. In recent years, British

4. Neonatal Reflexes: Students can gain a better understanding of neonatal reflexes by seeing

them in action. Have students with access to infants review the major reflexes identified in Table

5.2. Then ask them to try identifying whether these reflexes still exist (or have disappeared) in

the infants they know.

5. Maturation: In connection with the material on early and late maturation in adolescence, ask

students of both sexes to describe their experiences about early versus late maturation and

6. Ideal Age: Have students interview adults between ages 20 and 100 on their current physical

status and how that status has changed with time. Also, have students ask each person about their

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7. Impact of Physical Aging: In order to get a hands-on experience concerning the impact of

physical aging, have students interview four family members or friends from the following: 35-

45 years old, 45-55 years old, 55-65 years old, and someone 66 or older, and ask them to respond

to the following questions:

• On a scale from 1 (worst) to 10 (best), how would you rate your overall physical ability?