Chapter 11 Independent Questions
I. Physical Changes
In adolescence, elevated hormones trigger changes in the: (a) sex organs, (b) brain (cognitive
development), and (c) bones, muscles, and other body organs (motor skills).
A. The Endocrine and Reproductive Systems
1. (a) Why is the pituitary gland considered the most important or master gland?
The pituitary gland triggers the release of hormones from other glands; thus, it is sometimes
called the master gland. For example, the thyroid gland secretes thyroxine only when it receives
a signal in the form of a specific thyroid-stimulating hormone secreted by the pituitary.
(b) Differentiate between primary and secondary sex characteristics.
Changes in primary sex characteristics include growth of the testes and penis in the male and of
the ovaries, uterus, and vagina in the female. Changes in secondary sex charac- teristics include
breast development in girls, changing voice pitch and beard growth in boys, and the growth of
body hair in both sexes.
Sexual Development in Girls
2. Is menarche or first menstruation typically the first sign of puberty growth in females? If
not, what is (see Figure 11.1)?
No, The first steps are the early changes in breasts and pubic hair,
3. (a) What is the secular trend, and (b) what are potential causes of this trend?
the decline in the average age of menarche, along with changes such as an increase in average
height for both chil- dren and adults, that happened between the mid-19th and mid-20th
centuries in Western countries and occurs in devel- oping nations when nutrition and health
4. Although it’s possible to become pregnant once menstruation begins, why might it be
unlikely for some females?
Sexual Development in Boys
5. Do beard growth, the height spurt, and voice lowering typically suggest boys are just
starting or nearing the end of puberty? end
(b) What physical changes would adolescent boys typically notice first (see Figure 11.1)?
Timing of Puberty
6. Recall that early and late timing is one type of individual difference (chapter 1). The
effects of entering puberty early have been of considerable research interest. Early puberty
is the predictor or independent variable. Identify the dependent variables or correlates of
early puberty for (a) girls and (b) boys.
a) Although early maturing girls didn’t smoke, drink alcohol, or do drugs any more or less than
other girls their age, they did tend to belong to groups of older peers who displayed antisocial
behaviours and who smoked, drank alcohol, and did drugs. Associating with older youths who
get into trou- ble may set these early maturing girls up for sexual and school problems later on.
b) Among boys, the earlier their development, the more positive their body image, the bet- ter
they do in school, the less trouble they get into, and the more friends they have
B. Other Body Systems
7. Synaptogenesis and synaptic pruning influence grey matter volume in our brain.
(a) Define synaptogenesis and synaptic pruning (see margins on pp. 100-101)
synapto- genesis (the overproduction of neural branches and connection) followed by
synaptic pruning—this follows the “use it or lose it” principle whereby those neural
connec- tions that are not used will wither and die.
(b) What happens to the levels of grey matter volume in adolescence (see Figure 11.2 “(A)
Gray Matter (cc)”?
(c) Is this change in grey matter advantageous? Why or why not?
A decreasing amount of GM may reflect the pro- cess of pruning.
(d) Brain regions mature at different rates. What is the brain region that reaches adult
levels the latest?
areas within the frontal cortex (e) What behaviours/cognitions is the brain region you identified in 7d associated with?
linked to the control of impulses, judgment, and decision mak- ing, which raises concerns
about adolescents’ degree of responsibility for their actions
(f) What information-processing concept would be most related to the brain region you
identified in 7d?
Executive control strategies
8. Myelinization influences white matter volume.
(a) Define myelinization (see margin on p. 102)
a process in neuronal develop- ment in which sheaths made of a substance called myelin
gradually cover individual axons and electrically insulate them from one another to
improve the conductivity of
(b) Does our white matter volume rise or decline in adolescence (see Figure 11.2 “(B)
White Matter (cc)”?
(c) Is this change advantageous? Why or why not?
The corpus callosum (integrates the activities of the left and right sides of the brain) and the
pathways connecting speech reception (Wernicke’s area) with speech production (Broca’s
The Skeletal System (Bone Development)
9. Apart from the first year of life where infants grow 25-30 cm and triple their body weight,
adolescence is the second stage of development associated with the most gains in height
and weight. When do most adolescent boys and girls attain their adult height?
Girls attain most of their height by age 16, while boys continue to grow until they are 18 to
20 years old
10. The cephalocaudal and proximodistal patterns of bone development are reversed in
adolescence. Explain how this pattern of bone development affects adolescents’ bodies as
well as how it may contribute to stereotypes about adolescents.
a teenager’s hands and feet are the first body parts to grow to full adult size, followed by the
arms and legs; the trunk is usually the slowest part to grow. Stereotype is that they look
awkward and are uncoordinated. 11. When do boys catch up and outperform girls in activities that require coordination as a
result of their joint development?
12. Are female teens stronger than male teens? Why or why not (note nature and nurture
reasons provided in your textbook)?
Heart and Lungs
13. (a) What changes do adolescents’ heart and lungs undergo in adolescence?
the heart and lungs increase considerably in size, and the heart rate drops.
(b) Following puberty, boys have a clear advantage in _____, _____, ____, and _____.
This gives boys’ (on average) a greater capacity for sustained physical effort.
endurance as well as in size, strength, and speed.
II. Adolescent Health
A. Health Care Issues
14. (a) Define sensation-seeking.
a desire to experience increased levels of arousal such as those that accompany fast driving or
the “highs” that are associated with drugs
(b) Sensation-seeking is associated with accident and injury rates for teens. Canadian data
reveals that auto accidents are the leading cause of death for all Canadian teens (auto
accidents account for 40% of all teen deaths; suicide accounts for 25% of all teen deaths).
According to Canadian statistics presented in your textbook, road crash deaths have
decreased _____ %; alcohol-related deaths have decreased _______ %.
B. Sexual Behaviour
15. What percent of 14 to 15 year olds are sexually active? 12-13
(b) What about 15 to 17 year olds?
(c) What about 18 to 19 year olds?
Below is some additional information about sexually transmitted infections (STIs) that your
textbook doesn’t address. (The information in the box below will be tested in the multiple-
choice section of the midterm#2 exam.)
There are two main categories of sexually transmitted diseases (STDs), which are now
referred to as sexually transmitted infections, or STIs: (1) bacterial STIs (caused by bacteria),
and (2) viral STIs (caused by viruses).
Bacterial STIs, such as gonorrhea, syphilis, and chlamydia, are often cured with antibiotics.
Viral STIs, such as HIV, HPV (genital warts), herpes, and hepatitis — the four Hs — have no
cure. However many of the destructive and serious symptoms can be alleviated with treatment.
Additionally, there are vaccines available to help prevent both HPV and hepatitis (there are no
vaccines available for herpes and HIV). Although you can ask your health care provider if
you’d like to be vaccinated for HPV and hepatitis, don’t assume that these vaccinations will
guarantee you’ll be HPV or hepatitis free (this is similar to the flu shots and flu prevention).
In addition to bacteria and viruses, STIs can also be caused by protozoa (trichomoniasis)
and other organisms (crabs/pubic lice and scabies). These STIs can be cured with antibiotics or
16. Back to the textbook… Chlamydia is the most commonly reported STI in Canada.
(a) According to your textbook, are there any symptoms for Chlamydia?
(b) What might chlamydia lead to, if left untreated?
Left untreated, chlamydia can lead to pelvic inflammatory disease (PID), ectopic
pregnancy, and infertility in women and a number of genital and urinary tract disorders in
(c) If you notice a growth on your genitals, you may have genital warts, which may be
caused by the human papillomavirus (HPV). Although not all warts are caused by HPV,
why should you be concerned about the consequences of this?
17. Most public health advocates suggest that an effective sex education program should not
merely target information. (a) What else might a sex education program focus on?
Most suggest that pro- grams that include training in social and decision-making skills
(b) Is there any evidence to suggest that making condoms available promotes sexual
Moreover, making condoms more readily available to teenagers does not increase their
rate of sexual activity but does increase the use of condoms by teenagers who are already
C. Teenaged Pregnancy
18. (a) Is teenage pregnancy on the rise in Canada?
(b) United States has the highest teenage pr