LECTURE ONE
PUBERTY AND HEALTH
SPRING 2022
KIRAGU NDERO
WHAT IS PUBERTY
 Puberty is the process by which a person
attains sexual maturity and the ability to
reproduce
The biological changes of puberty which signal
the end of childhood result in rapid growth in
height and weight( second only to change in
pace in infancy)
The body changes in form and proportion and
attainment of sexual maturity
puberty
 these dramatic changes are part of a long
complex process of maturation that begins in
the womb
The changes produce psychological
ramifications that continue to adulthood
How puberty begins?
 sharp increase in production of sex hormones
Anytime between the age of 5 -9 even before
any physical changes appear
 adrenal glands begin to produce large
amounts of estrogens which play a part in the
growth of pubic hair, armpit and facial hair
 a few years later the ovaries step up their
output of estrogen which stimulates the
growth of female genitals and breasts
How puberty begins?
In boys the testes increase the manufacture of
androgens particularly testosterone e which
stimulate the growth of male genitals , muscle
mass and body hair
 boys have more testosterone than girls
Girls have more estrogen than boys
Testosterone influence the growth of the
clitoris , the bones, pubic and axillary hair
How puberty begins
 the precise time when this burst of hormonal
activity occurs is related to reaching a critical
body weight
 leptin , a protein hormone secreted by fatty
tissue may trigger the onset of puberty
An accumulation of leptin in the body triggers the
hypothalamus ( in the limbic system) sending
pulsating signals to the nearby pituitary gland
This triggers sex glands to increase secretion of
hormones
How puberty begins
 over weight girls therefore enter puberty
earlier than thin girls
Increased hormones are related to mood
changes for example aggression in boys and
both aggression and depression in girls
Other variables like sex, age temperament are
equally import
Environmental factors
Adolescents tend to begin sexual activity more
in accord more in accord to what their friends
do
 a girl with a father at home and one who
engages in sports may have less time for
sexual activity ( delayed sexuality) despite
pressure from the hormones
Timing of puberty
There is a seven year range for the onset of
puberty
 the process take typically four for both sexes
and takes 2 or 3 years earlier for girls than for
boys
 some people move quickly through
adolescence while others move slowly
 girls typically begin to show pubertal change
at 8 to 10 years of age
Timing of puberty
 Some girls show the signs as aerly as 7 or as
late as 14
 average entry age of boys is 12 though it can
show any time between 9 and 16
 there is generally a lowering of age of onset
according to developmental psychologists
Adult height and weight is reached faster
because of factors like increased nutrition
Timing of puberty
 children are heavier and better nourished
compared to 100 years ago
Female
Growth of breasts:
8 – 13
Growth of pubic hair:
8 – 14
Body growth:
9 – 15
Menarche :
10 – 16
Underarm hair:
2 years after appearance of pubic hair
Increased output of oil and sweat producing glands which may
lead to acne) 10 - 16
Timing of puberty
male
 growth of testes scrotal sac 10 -13
 Growth of pubic hair 12 -16
 body growth 10 – 16
 growth of penis, prostate gland and seminal vesicles 11
– 14
 change in voice 11 - 14
 First ejaculation of semen 11 – 14
 Facial and under arm hair 14 – 18
 Increased output of oil and sweat producing glands
which may lead to acne) 14 - 18
Adolescence growth spurt
growth spurt
sharp in height and weight that precedes sexual
maturity
Secular trend
Trend that can be seen observing several
generations such as a trend towards earlier
attainment of adult height and sexual maturity
which began a century ago
Adolescence growth spurt
Both boys and girls reach their maximum
height by 18
Boys grow larger overall; wider shoulders and
legs longer relative to the trunk ;forearmas
longer relative to to his upper arms and his
height
Adolescence growth spurt
A girls pelvis widens to make child bearing
easier and layers of fat are laid down just
under the skin giving a more rounded
appearance
 the adolescence growth spurt typically affects
all skeletal and muscle dimensions
 even the eye grows faster causing and
increase in near sightedness
Adolescence growth spurt
The lower jaw becomes thicker longer and
thicker
The jaw and nose project more
The incisor teeth become more upright
Because each change follows its timing
Parts of the body might be out of proportion
causing familiar teenage gawkiness( because of
unbalanced, accelerated growth)
Primary sex characteristics
Primary sex characteristics
These are organs necessary for reproduction
females
Ovaries uterus and the vagina
Male
Testes , prostate gland , penis and seminal
vesicles
During puberty these organs grow and mature
Secondary sex characteristics
Secondary sex characteristics
These are physiological signs of sex maturation
that do not directly involve the sex organs like
breasts of the female and the broad shoulders of
the males, voice, skin texture, muscular
development etc.
 first sign in the girl is the budding of breasts and
the growth of pubic hair. Nipples enlarge and
protrude breasts get that conical shape etc.
Signs of sexual maturity
Males
The principle sign of sexual maturity is the
production of sperms
Its timing is highly variable but a quarter of 15
year old boys have sperm in the urine ( wet
dreams0 or nocturnal emissions connected to
an erotic dream
Signs of sexual maturity
Females
The principle sign of sexual maturity for females is
menstruation a monthly shedding of tissue from
the lining of the womb( menarche)
Factors influencing menarche onset:
Strenuous exercise causes delay
Nutrition ( balanced diets good)
Genetic, emotional, and environmental
influences are equally important
Effects of Physical Development
 Because rates of physical development vary so widely
among teenagers, puberty can be a source of pride or
embarrassment.
 Early maturing boys tend to be physically stronger,
taller, and more athletic than their later maturing
peers; this can contribute to differences in popularity
among peers, which can in turn influence the
teenager’s confidence.
 Some studies show that boys who mature earlier tend
to be more popular and independent but are also at a
greater risk for substance abuse and early sexual
activity
Effects of Physical Development
Early maturing girls may face increased
teasing and sexual harassment related to their
developing bodies, which can contribute to
self-consciousness and place them at a higher
risk for anxiety, depression, substance abuse,
and eating disorders
Effects of Physical Development
Girls and boys who develop more slowly than
their peers may feel self-conscious about their
lack of physical development;
 some research has found that negative
feelings are particularly a problem for late
maturing boys,
who are at a higher risk for depression and
conflict with parents (Graber et al., 1997) and
more likely to be bullied (Pollack & Shuster,
Effects
Menarche is more than a physical event it is a
concrete symbol of the shift from girl to
woman
 ovulation however may take 12 to 18 months
more to develop ( girls however are better
assuming they can in fact get pregnant)
 many girs have mixed feeling about
menstruation but most take it in their stride
Effects
 the better prepared a girl is the better and
the more positively she will take her
menarche
Parents , teacher and professional should give
them information to cope and adapt
Evolution, Heredity and the
environment
As human ancestors left the forest to feed on
the savannahs, and formed hunting societies
in open plains the human mind and behaviuor
changed
 how did evolution come about?
Natural selection
This is the evolution process that favors those
individuals of the species who are best
adapted to survive and reproduce
 Charles Darwin wrote the origins of species in
1859 and noted:Organisms reproduce at rates that would
cause enormous increase in their population
and yet populations remain constant
Natural selection
 Those who survive dominate and pass on
their genes to the next generation
 in other words those who survive are better
adapted to their world than non survivors
producing a gradual modification of the
species
If the environment changes another set of
survival characteristics are needed
Adaptive behaviour
 Adaptive behavior is a modification of
behavior that promotes the organisms survival
In the natural habitat
 all organisms adapt to specific places
climates, food sources and ways of life in
order to survive
 in humans closeness to caregivers ( parents
etc.) for feeding and protection from danger
promote survival
Evolutionary developmental
psychology
 an extended childhood evolved because
children require time to develop a large brain
 they need to learn complexity of human
societies
 humans also take time to become
reproductively mature
 they also need skills to become competent
Evolutionary developmental
psychology
Many evolved psychological mechanisms are
domain specific ( they apply only to specific
aspects of a persons make up)
 for example information processing required
in mastering how to hunt a porcupine
 many specializations are learn and they keep
changing. You no longer need to learn how to
hunt a porcupine your are better of mastering
the key board today
Evolutionary developmental
psychology
In food scarce communities our ancestors
used to gorge when ever food was available
and craved for high calorie food. This today
causes obesity where food is plentiful
Evolution gives the human body structure and
biological potentiality which helps people
develop diverse cultures aggressive or pacific,
egalitarian or autocratic.
Evolutionary developmental
psychology
 human biology allows a broad range of
cultural possibilities
Albert Bandura’s social cognitive theory
emphasizes reciprocal connection between
behaviour, environment and person
Evolution and the genetic process
 genetic influences on behaviour evolved over
time across species
 The many traits and characteristics that
developed over time are retained in our DNA
DNA is not just inherited from our parents , it
is what we have inherited as a species
Genotype and phenotype
 Genotype is a person genetic heritage that is
the actual genetic potential
 phenotype is the way individual genotype has
been expressed out of the many possibilities
Behavior genetics seeks to understand the
influence of heredity to the environment
To what extent do people differ as result of
genes, environment or a combination of both?
Behaviour genetics
 The relationship between behaviour and genetics, or
heredity, dates to the work of English scientist Sir Francis
Galton (1822–1911), who coined the phrase “nature and
nurture.”
 Galton studied the families of outstanding men of his day
and concluded, like his cousin Charles Darwin, that mental
powers run in families.
 Galton became the first to use twins in genetic research
and pioneered many of the statistical methods of analysis
that are in use today. In 1918 British statistician and
geneticist Ronald Aylmer Fisher published a paper that
showed how Gregor Mendel’s laws of inheritance applied
to complex traits influenced by multiple genes and
environmental factors.
Mendel’s laws of inheritance
Mendel's law of segregation
Cross of a purple-flowered and a white-flowered
strain of peas. R stands for the gene for purple
flowers and r for the gene for white flowers.
Encyclopædia Britannica, Inc.
Behaviour genetics
The first human behavioral genetic research
on intelligence and mental illness began in the
1920s, when environmentalism (the theory
that behaviour is a result of nongenetic factors
such as various childhood experiences)
became popular and before Nazi Germany’s
abuse of genetics made the notion of
hereditary influence abhorrent.
Behaviour genetics
 Although genetic research on human
behaviour continued throughout the following
decades, it was not until the 1970s that a balanced
view came to prevail in psychiatry that recognized the
importance of nature as well as nurture.
 In psychology, this reconciliation did not take hold until
the 1980s. Much behavioral genetic research today
focuses on identifying specific genes that affect
behavioral dimensions, such
as personality and intelligence, and disorders, such as
autism, hyperactivity, depression, and schizophrenia.
Adolescence and health
Adolescence and health
The world is now home to the largest cohort
of adolescents in history – 1.2 billion people
between the ages of 10 and 19. How they
develop and grow has implications that
reverberate across generations.
 Just some of the factors that impact the
development of today’s adolescents include
social media, urbanization, unhealthy diets,
armed conflict, climate change and migration.
Adolescence and health
While adolescents have a better chance of
improving their health and well-being now more
than ever, an estimated 1.2 million still die each
year – mostly from preventable causes.
Many lack access to the essential information,
quality services and protective environments they
need to stay healthy and well.
https://www.unicef.org/health/adolescenthealth-and-well-being
Adolescence and health
Diseases like malaria and cholera still take the
lives of adolescents worldwide, especially in
humanitarian settings, where health supplies and
services, and water, sanitation and hygiene
facilities are scarce.
In low- and middle-income countries, home to 90
per cent of today’s adolescents, young people are
among the populations most at risk of
contracting HIV, and the group least likely to have
access to treatment.
Adolescence and health
Adolescents are the only age group for whom
AIDS deaths are on the rise.
Increasingly unhealthy diets, inactive
lifestyles, mental ill-health, alcohol and
tobacco use, and environmental risks such as
air pollution are some of the most prominent
issues facing adolescents today.
Adolescence and health
For adolescent girls, the onset of puberty brings
additional threats. Poverty and discriminatory
social and gender norms can restrict girls’ life
choices and exclude them from educational,
social and economic opportunities.
Each year, an estimated 23 million adolescent
girls become pregnant.
Maternal mortality – in many cases linked to child
marriage – is a leading cause of death for girls
aged 15–19. Female genital mutilation can also
cause life-threatening health complications.
Adolescence and health
 Mental health conditions also take an immense toll.
Over half of these conditions surface during the second
decade, with depression emerging as a leading cause
of adolescent illness and disability. For 15- to 19-yearolds worldwide, self-harm is a top killer.
 What’s more, some 70 per cent of premature deaths
are associated with behaviours, like smoking or binge
drinking, that arise during adolescence. Most are linked
to non-communicable diseases, including diabetes and
pollution-related conditions.
Our Pathway to a Healthier Future
NOVEMBER 14, 2020
A manifesto from young leaders around the world:
Living through the COVID-19 pandemic has shown
us that our health cannot be taken for granted. Our
health and the health of future generations depend
on the actions and choices we make today. As
young people, we are concerned about five
increasingly unhealthy trends, which are only being
exacerbated by the COVID-19 pandemic:
Our Pathway to a Healthier Future
NOVEMBER 14, 2020
 The rate of obesity among 10-19-year-olds globally is
5 times higher today than it was in 1990.
 One third of adolescents worldwide consume alcohol.
 Global prevalence of tobacco use among adolescents
is 19% across high, low, and middle income countries.
 Over 90% of those under 15 years of age breath toxic
air everyday.
 Up to 20% of young people experience mental illhealth in any given year and self-harm has become
the 3 leading cause of death among 15-19-year-olds.
Our Pathway to a Healthier Future
NOVEMBER 14, 2020
These factors have a negative impact on our
daily lives and increase our risk of noncommunicable diseases (NCDs), which today
account for 70% of global mortality.
 We believe that young people can, and must,
turn the tide on these trends. But how do we
get there? Our pathway to a healthier world
calls for:
Our Pathway to a Healthier Future
NOVEMBER 14, 2020
Young people to be aware.
 Together we must help young people understand the
benefits of investing in their own health. It is important
that we recognize and examine the factors that
influence our behaviors and our environments, unlearn
unhealthy behaviors, develop healthier habits, and
create new standards for living. Today, a growing
community of young creators around the world are
turning to art and blogging to spread messages about
health and well-being through the Voices of
Youth platform.
Our Pathway to a Healthier Future
NOVEMBER 14, 2020
 We are also seeing an increase in grassroots
movements for awareness-raising led by young people
in places like Jakarta, Indonesia where the Youth
Movement for FCTC aims to inform youth about how
they are affected by the tobacco industry and how
tobacco use affects their health.
 These are only a few of the many examples aiming to
build awareness in young people. But, we need
increased efforts like these, led by youth for youth, to
raise awareness on NCD burden and risk factors in ways
that are engaging, relevant, motivating, and tailored to
our needs and realities.
Our Pathway to a Healthier Future
NOVEMBER 14, 2020
Young people to be empowered.
As young people, we require the abilities and
confidence to maintain and advocate for healthy
lifestyles. This must be sustained by applied
knowledge, skills, resources, and an environment
that nurtures self-development. Youth-led groups
are becoming increasingly involved with
empowering everyday citizens to take action for
promoting health and healthier environments.
Our Pathway to a Healthier Future
NOVEMBER 14, 2020
For example, in Bogota, Colombia, the youth
organization El Derecho a No Obedecer, has been
building the capacity of young people to take
personal and collective actions against air
pollution through their public conversation
spaces and Air Day campaigns.
We need greater investments towards evolving
our capacities, resources, and agency to develop
and implement our own ideas and solutions to
promote healthy lifestyles.
Our Pathway to a Healthier Future
NOVEMBER 14, 2020
Young people to drive action.
As young people, we have a lot to contribute but
a shift in power relations is needed in order for
us to create meaningful and lasting change.
Around the world, more and more young people
are part of shaping the policies and services
affecting their health.
Our Pathway to a Healthier Future
NOVEMBER 14, 2020
 In Jamaica, for example, the combination of
establishing of a Health Ministry Adolescent Policy
Working Group, U-Report polling, and partnership with
the Jamaica Youth Advocacy Network (JYAN) have
allowed youth-proposed solutions to be taken up by
the Ministries of Health and Education towards
meeting the health needs and rights of young people.
 We need to be treated as equal partners, leaders,
problem solvers, and agents of change in creating the
policies and legal actions required to reduce NCD risk
factors and burden globally.
Our Pathway to a Healthier Future
NOVEMBER 14, 2020
On behalf of young people around the world,
we stand committed to tackling the most
pressing health issues facing our generation.
Join us and the UNICEF-AstraZeneca YHP
Partnership as we work to ensure that all
young people are aware, empowered, and
actively driving change towards a healthier
future for ourselves, our communities, and
our planet.
Our Pathway to a Healthier Future
NOVEMBER 14, 2020
UNICEF-AstraZeneca 2020-2021 Young Leaders
Alejandro Daly, Colombia/Venezuela; National Coordinator, El Derecho A No Obedecer
Anjali Singla, India; Psychologist and Principal Coordinator, Movement for Global Mental Health
Breanna Hyde, Belize; Child Advisory Board, National Committee for Family and Children Belize
David Henry, St. Lucia; Founder, ReThink Youth
Jerry Azilinon, Senegal/Benin; HeForShe Ambassador, UN Women
Margianta Surahman Juhanda Dinata, Indonesia; Spokesperson, Youth Movement for the Framework
Convention on Tobacco Control
Omnia El Omrani, Egypt; Liaison Officer for Public Health Issues, International Federation of Medical
Students Association
Rasheem Martin, Jamaica; Zonal Coordinator, U-Report Jamaica
Vinicius Gaby, Brazil; University of Sao Paulo Medical Student, Communicator at Meu Amigo Médico
Winfred Apio, Uganda; Programme Manager, Uganda Youth and Adolescents Health Forum
https://www.voicesofyouth.org/unicef-astrazeneca-youth-manifesto