Chapter 11: Exam 4 Flashcards
G. Stanley Hall
(1904) believed that adolescence is marked by turmoil and used the German phase strum and drang (“storm and stress”) to refer to the conflicts of adolescence.
Puberty
The biological stage of development characterized by changes that lead to reproduction capacity.
Feedback Loop
A system in which glands regulate each other’s functioning through a series of hormonal stages involving the hypothalamus, pituitary gland, the gonads - the ovaries in females and testes in males - and hormones.
CONTROLS PUBERTY
Hypothalamus
Signals the pituitary glands releasing hormones that control physical growth and the gonads
Gonads
Respond to pituitary hormones, increasing their production of sex hormones (androgens and estrogens)
Sex Hormones
Further stimulate the hypothalamus, perpetuating the feedback loop.
Primary Sex Characteristics
The structures that make reproduction possible
*Girls (ovaries, vagina, uterus, and fallopian tubes)
*Boys (penis, testes, prostate gland, and seminal vesicles)
Secondary Sex Characteristics
Physical indicators of sexual maturation - such as changes to the voice and growth of bodily hair - do not directly involve reproductive structures.
involves breast development, deepening of the voice, and the appearance of facial, pubic, and underarm hair.
The Adolescent Growth Spurt
*Stable growth patterns in height/weight end abruptly with the adolescent growth spurt.
*Girls start to spurt in height sooner than boys (average age of a little more than ten)
*Boys start to spurt two years later
*Girls reach their peak growth in height at about 12 to 14 years old
***Overall, boys add an average of 14 1/2” during the spurt and the girls add a little more than 13”.
Enormous amounts of food to fuel their growth spurts
Active 14 to 15 year old boys may consume 3,000 to 4,000 calories a day without becoming obese.
asynchronous growth
unbalanced growth, such as the growth that occurs during the early part of adolescence and causes many adolescents to appear gawky (different parts of the body grow at different rates)
*Hands and feet mature before the arms and legs do, may complain of big hands or feet
*Legs reach their peak growth before the shoulders and chest
*Boys stop growing out of their pants about a year before they stop growing out of their jackets.
Truth or Fiction
American adolescents are growing taller than their parents
Fiction
The statement is too general to be considered true. The average height for adults is greater than it was 100 years ago, but the upward trend seems to have stopped for middle-and-upper-class children. It does seem to remain true for children of lower socioeconomic status.
Secular Trend
A historical trend toward increasing adult height and earlier puberty.
*Swedish boys and girls grew more rapidly in 1938 and 1968 than they did in 1883 and ended up several inches taller.
*At age 15, boys were more than 6” taller, and girls were more than 3” taller, on average than their counterparts from the previous century.
***Trend documented in nearly all European countries in the U.S.
However, children from the middle-and upper-class families in developed nations no longer grow taller, whereas their poorer counterparts continue to gain.
Signs of Puberty in Boys
*Accelerated growth of the testes begins on average 11 1/2 plus or minus two years
*Penis growth spurt begins a year later, and still later, pubic hair develops
*Underarm and facial hair appears at about 15 (only 1/2 of American boys shave by the age of 17)
*Voice deepens because of growth of the “voice box,” or larynx, and lengthening of the vocal cords at 14 or 15
Semen
The fluid that controls sperm and substances that nourish and help transport sperm.
*Boys typically ejaculate seminal fluid by age 13 or 14
Nocturnal Emissions (Wet Dreams)
Emission of seminal fluid while asleep (mature sperm are found in ejaculatory emissions by the age of 15)
Gynecomastia
Enlargement of breast tissue in males stems from the small amount of female sex hormones secreted by the testes.
*Nearly half of all boys experience this which usually declines in a year or two
Epiphyseal Closure
The process by which the cartilage that separates the long end of a bone from the main part of the bone turns into bone.
Signs of Puberty in Girls
*Pituitary glands signal ovaries to boost estrogen production
*Estrogen stimulates breast tissue growth (“breast buds”) as early as 8 or 9, but usually ten years old.
*Breasts typically reach full size in about three years, but the mammary gland does not mature fully until a woman has a baby
*Develop pubic and underarm hair at age 11
*Estrogen causes the labia, vagina, and uterus to develop during puberty, and androgens cause the clitoris to develop.
Menarche
The onset of menstruation
*Current mean age in the U.S. is 13
Hypothesis for earlier ages of puberty?
*Girls reach a certain body weight that triggers pubertal changes because fat cells secrete a protein that signals the brain to secrete hormones that raise estrogen levels
- Menarche comes later to girls who have a lower percentage of body fat
Regulation of the Menstrual Cycle
*Estrogen and Progesterone levels in girls vary and regulate the menstrual cycle
*Following menstruation, the sloughing of the endometrium tissue - - estrogen levels increase, leading to more growth of endometrium tissue.
*Girls begin to ovulate 12 to 18 months after menarche
Truth or Fiction
Girls are fertile immediately, usually after their first menstrual period
Fiction
Girls usually begin to ovulate 12 to 18 months after menarche