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FRHD 1010 (300)
Chapter 9-10

FRHD 1010 Chapter Notes - Chapter 9-10: Anemia, Water–Electrolyte Imbalance, Eating Disorder


Department
Family Relations and Human Development
Course Code
FRHD 1010
Professor
Susan Chuang
Chapter
9-10

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CHAPTER 9 ADOLESCENCE
Puberty
PUBERTY, the time between the first onrush of hormones and full adult physical development. Puberty
usually lasts 3-5 years. Many more years are required to achieve psychological maturity.
This process normally starts between ages 8-14
Most physical growth and maturation end about 4 years after the first signs appear, although some
individuals add height, weight, and muscle until age 20 or so
For girls, the observable changes of puberty usually begin with nipple growth and pubic hairs.
MENARCHE, a girl’s first menstrual period, signaling that she has begun ovulation. Pregnancy is
biologically possible, but ovulation and menstruation are often irregular for years after menarche. (12
years and 8 months).
SPERMARCHE, a boy’s first ejaculation of sperm. Ejaculations can occur as early as infancy, but
ejaculation signals sperm production. Spermarche may occur during sleep or via direct stimulation.
Unseen Beginnings
The entire process begins with an invisible event: a marked hormonal increase.
HORMONES, an organic chemical substance that is produced by one body tissue and conveyed via the
bloodstream to another to affect some physiological function.
Regulate hunger, sleep, mood, stress, sexual desire, etc.
PITUITARY, a gland in the brain that responds to a signal from the hypothalamus by producing some
hormones, including those that regulate growth ad that control other glands, among them the adrenal and
sex glands.
The pituitary produces hormones that stimulate the adrenal glands.
ADRENAL GLANDS, two glands, located above the kidneys, that produce hormones.
It follows the routes, known as HPA (HYPOTHALAMUS-PITUITARY-ADRENAL) AXIS, a
sequence of hormone production.
HPG (HYPOTHALAMUS-PITUITARY-GONAD) AXIS, another sequence of hormone production.
Gonadotropin-releasing hormone (GnRH) is released by the hypothalamus, causing the pituitary
to release gonadotropins, which in turn activate the gonads.
As a result, the gonads enlarge and increase their production of sex hormones, chiefly estradiol in
girls and testosterone in boys.
ESTRADIOL, a sex hormone, considered the chief estrogen. Females produce much more than males do.
TESTOSTERONE, a sex hormone, the best known of the androgens (male hormones), produced much
more in males than in females.
Males are twice as likely as females to become schizophrenic, whereas females are twice as likely to
become depressed.
Sexual Maturation
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PRIMARY SEX CHARACTERISTICS, the parts of the body that are directly involved in
reproduction, including the vagina, uterus, ovaries, testicles, and penis.
SECONDARY SEX CHARACTERISTCS, physical traits that are not directly involved in reproduction
but that indicate sexual maturity, such as a man’s beard and a woman’s breasts.
Age Puberty
Genes and Gender
Genes on the sex chromosomes have a marked effect.
Female height spurt occurs before menarche, whereas for the boys it occurs after spermarche.
Body Fat
Heavy girls reach menarche years earlier than malnourished ones do.
Most girls must weight at least 45kg before they experience their first period.
Puberty has occurred at younger ages since past centuries due to secular trend, more food has
allowed biological advances.
LEPTIN, a hormone that affects appetite and is believed to affect the onset of puberty. Leptin levels
increase during childhood and peak at around age 12.
Leptin affects appetite in females more than it does in males, and body fat is more closely
connected to the onset of puberty in girls than in boys.
Too Early, Too Late
Girls
Early maturing girls tend to have lower self-esteem, more depression, and poorer body image
than do other girls.
Delayed puberty in girls can be hereditary, but it can also be due to malnutrition, chromosomal
abnormalities, genetic disorders, or illness.
If puberty is delayed, girls may become distressed by the differences in their bodies compared to
others.
Boys
Early-maturing boys have been more aggressive, law-breaking, and alcohol-abusing.
Boys who reach puberty late may also have problems, becoming more anxious, depressed, and
afraid of sex than other boys.
Growing Bigger and Stronger
GROWTH SPURT, the relatively sudden and rapid physical growth that occurs during puberty. Each
body part increases in size on a schedule: weight usually precedes height, and growth of the limbs
precedes growth of the torso.
Sequence: Weight, Height, and Muscles
As the bones lengthen and harden, children eat more and gain weight.
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At age 17, the average girl has twice the percentage of body fat as her male classmate, whose
increased weight is mostly muscle.
Lungs triple in weight; adolescents breathe more deeply and slowly.
The heart doubles in size as the heart beat sows, decreasing the pulse rate while increasing blood
pressure.
Red blood cells increase in both sexes, but dramatically more so in boys, which aids oxygen
transport during intense exercise.
Both weight and height increase before muscles and internal organs: Athletic training and weight
lifting should be tailored to an adolescent’s size the previous year to protect immature muscles
and organs.
Sports injuries are the most common school accidents.
Only one organ, the lymphoid system (which includes the tonsils and adenoids), decreases in size
so teens are less susceptible to respiratory ailments.
Skin and Hair
Because of hormones, secretion of oils increases, which results in a greater susceptibility to acne.
During puberty, hair on the head and limbs become coarser and darker.
Body Rhythms
CIRCADIAN RHYTHMS, day-night cycle of biological activity that occurs approx. every 24 hours.
The hypothalamus and the pituitary regulate the hormones that affect biorhythms of stress,
appetite, sleep, and so on.
Hormones of the HPA axis at puberty cause a phase delay in sleep-wake cycles, making many
teens wide awake and hungry at midnight but half asleep with little appetite or energy all
morning.
Biology (circadian rhythms) and culture (socializing with friends and technology) work in
opposite directions, making teens increasingly sleep-deprived with each year of high school.
25% of Canadians are sleep-deprived, while 60-70% of Canadian students report being very sleep
during their morning classes.
Nutrition
Teenagers often skip breakfast, eat at midnight, guzzle down soft drinks, and munch on salty, processed
snacks.
Their hormones affect their diurnal rhythms, including their appetites;
Also, they seek independence by eating what they want, when they want.
Diet Deficiencies
Deficiencies of iron, calcium, zinc, and other minerals are especially common after puberty.
Anemia is more common in girls
o Because menstruation depletes iron.
The recommended intake for calcium is 1300 mg, but teens consume less than 500 mg a day.
Body Image
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