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INTRODUCTION
TO
HUMAN GROWTH &
DEVELOPMENT
Dr. Nithin Kumar

INTRODUCTION
• Human growth and development are characterized and defined by the way in which we
change in size, shape, and maturity relative to the passage of time.
• It has been more common for the size of children to be assessed for reasons of classification and
organization that requires assessment at certain ages for specific reasons.
• However, the first longitudinal record we have of the growth of a child was the result of a desire to
apply scientific method to the natural world.
Patterns of Human Growth
2

GROWTH – DEFINITION
• It is the process of physical maturation resulting an increase in size of the body and various organs.
• It occurs by multiplication of cells and an increase in in intracellular substance.
• It is quantitative changes of the body.
3

DEVELOPMENT – DEFINITION
• It is the process of functional and physiological maturation of the individual. It is progressive increase in
skill and capacity to function.
• It is related to maturation and myelination of the nervous system.
• It includes psychological, emotional and social changes.
• It is qualitative aspects.
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HISTORICAL
BACKGROUND
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How it all ��𲵲��…

“AGE OF ENLIGHTENMENT”
• in 18th century France, Between the death of Louis
XIV & emergence of Napoleon Bonaparte (1715-
1799)
• a movement away from religious and monarchical
authority and toward a more liberal and empirical
attitude.
• natural scientists and philosophers believed that
people’s habits of thought were based on
irrationality,
polluted by religious dogma, superstition, and over-
adherence to historical precedent and irrelevant
tradition.
• The way to escape from this is to seek for true
knowledge in every sphere of life, to establish the
truth and build on it, thereby literally “enlightening”
People’s minds
6

GEORGES-LOUIS LECLERC(COMPTE DE
BUFFON (1707 – 88)
• interested in mathematics, natural science, and silviculture, the
cultivation of trees.
• premier horticulturist and arborist in France and was appointed by
King Louize XVth as the director of the Jardin du Roi
• king invited him to write a compendium on the herbs of France
• But Buffon decided such a compendium would be too narrow and
instead started working on a broader project that was to include all
that was known of natural history. - “Histoire Naturelle, Ge´ne´rale
et Particulie`re”
• Ending up with 36 volumes by the time of his death in 1788
• This included 15 volumes on quadrupeds, 9 on birds, 5 on minerals
and 7 “Supplementary Volumes.
7

BERNARD GERMAIN DE LAPEAUDE
• appointed as a sub-demonstrator in the Jardin in 1785
• further added 8 volumes to “Histoire Naturelle, Ge´ne´rale et
Particulie`re”
• These 8 volumes included 2 on reptiles, 5 on fish, and 1 on
Cetacea.
• However, it is the supplement to volume 14, published in 1778, that is
particularly interesting to us.
• As it contained record of the growth of a boy, Francois Gueneau De
Montbeillard (1759-1847).
8

PHILIBERT GUENEAU DE MONTBEILLARD
(1720 – 85)
• He would take an empirical interest in the growth of his own son
• had been measuring the height of Francois about every 6 months from his birth
until he was 18 years of age.
• Was a close friend of Buffon and their common interest in the natural
sciences
resulted in De Montbeillard being invited as a co-author
• Buffon wished to include this primary evidence of the course of human growth
•
9

RICHARD E. SCAMMON (1883 – 1952)
• Translated the measurements of De Montbeillard into SI units.
• He published his results in 1930 in the American Journal of Physical
Anthropology under the title of “The first seriatim study of human growth”
• Thus, for the first-time people in the English-speaking world were able to
look upon the pattern of growth exhibited by Francois Gueneau De
Montbeillard in the form of a chart.
10

THE DISTANCE CURVE OF GROWTH
• Scammon produced the “height-for-age” curve
known as a “height distance” curve
• “Growth” is not a linear process
• term “distance” to describe height achieved
• it is easy to visualize and understand the fact that a
child’s height at any age is a reflection of how far
that child has progressed toward adulthood.
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1. growth is a continuous process.
2. growth is not a linear process i. e., we do not gain the same amount of height during each
calendar year.
3. this growth curve has five distinct phases corresponding to
• relatively rapid growth in infancy
• steady growth in childhood
• a short period of rapid growth during the juvenile period
• a second period of rapid growth during adolescence
• very slow growth as the individual nears adulthood.
4. growth represents a most dramatic increase in size. Eg: Francois De Montbeillard grew from
about 50 cm at birth to over 186 cm at adulthood.
5. we stop growing and reach our adult height, during our late teenage years.
Observation from distance curve of growth
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• The fact that this growth curve shows constant
pattern eg: polynominal, sigmoidal, allows us to apply
mathematical “models” to the pattern of growth.
• These models are, in fact, parametric functions that contain
constants or “parameters.”
• Once we have found an appropriate function that fits the
raw data, we can analyze the parameters and by so doing
learn a good deal about the biological process responsible
for growth.
• Consequently, they can be used in research into human
growth.
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VELOCITY GROWTH CURVE
& GROWTH SPURTS

• The rate of change of size with time is called “growth
velocity”
• D’Arcy Thompson a famous British natural scientist &
mathematical biologist published a book titled “On Growth
and Form” in 1917
• He wrote, “An organism is so complex a thing, and growth
so complex a phenomenon, that for growth to be so uniform
and constant in all the parts as to keep the whole shape
unchanged would indeed be an unlikely and an unusual
circumstance. Rates vary, proportions change, and the
whole configuration alters accordingly.”
• While the distance curve, “showed a continuous succession
of varying magnitudes,” the curve of the rate of change of
height with time, “shows a succession of varying velocities.
15

• Distinct increase in growth rate or growth velocity
is termed “growth spurt”
• Following birth, two relatively distinct increases in
growth rate occur
• at 6-8 years  juvenile or mid-growth spurt
• at 11-18 years adolescent growth spurt
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• Another growth spurt occurs prior to birth between 20 and 30 weeks of gestation
• There is increase in height as well as weight
• Observed through intra-uterine ultrasound measurements of fetuses and extra-
uterine anthropometric measurements of pre-term infants
• Corresponds to rapid accumulation of fat during this period.
• Why?? Fat is a more efficient source of energy than protein or carbohydrate
• This significant source of energy is required by the infant during
immediate
post-natal period
18

• Pre-natal spurt and juvenile growth spurt may vary in
magnitude, but they seem to occur at similar ages both
within and between the sexes.
• Adolescent growth spurt demonstrates sexual
dimorphism in both magnitude and timing
• Males enter their adolescent growth spurt almost two
years later than females
• Changes includes extra height, muscle mass and fat
distribution
• Males demonstrate rapid increases in muscle mass
and females accumulate greater amounts of fat.
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OTHER PATTERNS OF GROWTH
• Pattern of growth in height is only one of several patterns of growth that
are found within the body
• Neural tissue (brain and head), lymphoid tissue (thymus, lymph nodes,
intestinal lymph masses), reproductive tissue (testes, ovaries,
epididymis, prostate, seminal vesicles, Fallopian tubes) as well as some
major organ systems (respiratory, digestive, urinary).
• Research on the growth of neural tissue must be targeted at fetal and
infant ages
• Research on the growth of reproductive tissue on adolescent or
teenage years when growth is at a maximum.
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• “Growth” is defined as an increase in size while “maturity” or “development” is an increase in
functional ability.
• All children who live in normal environmental circumstances will have a similar pattern of growth.
• Getting taller, heavier, fatter, and more muscular as well as changes in our body proportions till
we reach adulthood.
• We become more “mature”, when we experience an increase in our functional capacity with
advancing age with increasing ability to undertake physical exercise in terms of both magnitude
and duration
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• The figure shows three boys and three girls who are of
the same ages within sex.
• Even though they are the same age they demonstrate
vastly different degrees of maturity.
• The boy and girl on the left are relatively immature
compared to those on the right as depicted by their
indicators of maturity or “maturity
indicators”
• There is obvious development of secondary sexual
characteristics (breast and pubic hair in girls and genitalia
and pubic hair in boys), in addition to dramatic changes
in body shape, increases in muscularity in males and
increases in body fat in females
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• The end-point of growth is the size we attain by adulthood
• The end-point of maturity is when we are functionally able to successfully procreate.
• Not simply to be able to produce a viable sperm or egg, but to produce an offspring who
themselves may also procreate
• Thus, successful maturation requires not just biological maturity but also psycho-social and
behavioral maturity.
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• Because size is governed by factors other than the process of maturation, we cannot use an
absolute size to determine maturation.
• Use the appearance and relative size of structures rather than their absolute size to reflect
maturity.
• Also, use of various maturity indicators are secondary sexual development, skeletal maturity, and
dental maturity
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• Growth and development is both complex and extensive.
• Genetic, epigenetic, and environmental factors has an influence
• Environment has the potential to alter genetic blueprint we are born with affecting our ability to
achieving a particular adult size and shape.
• This environmental factor will affect primarily the endocrine system
•
28

• The anterior lobe or “adenohypophysis” of pituitary gland releases the major hormones
controlling human growth and development; growth hormone, thyroid stimulating
hormone, prolactin, the gonadotrophins (luteinizing and follicle stimulating hormone),
and
adrenocorticotropic hormone
• Normal growth is a result of a complex and at times exquisite relationship between the nervous
and endocrine systems.
• Growth hormone  release of insulin-like growth factor 1 (IGF-1) from the liver.
29

• IGF-1 directly affects skeletal muscle fibers and cartilage cells in the long bones to
increase the rate of uptake of amino acids and incorporate them into new proteins and
thus contributes to growth in length during infancy and childhood.
• At adolescence, the gonadal hormones or sex steroids (testosterone in boys, and
estrogen in girls) affects the growth spurt
• Hence, diagnosis of growth disorders becomes a complex and engrossing series of investigations
that increasingly requires an appreciation of both genetic, environmental and endocrine
mechanisms.
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• In order to assess the normality or otherwise of the growth of
children we use “growth reference
charts.”
• These charts depict both the average height to be expected
throughout the growing years (typically from birth to 18 years),
and the range of normal heights, in the form of percentile or
“centile” distributions
32

• Growth of children without any environmental constrain exhibits a
pattern more or less parallel to a particular centile or within some
imaginary “canal.”
• This phenomenon is termed “canalization” or “homeorrhesis.”
• This pattern is genetically determined
• This genetic potential for adult stature and the process of growth,
in an unconstrained environment, takes us inevitably toward that
target.
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• Waddington equates growth to the movement of a
ball rolling down a valley floor.
• The sides of the valley keep the ball rolling steadily
down the central course (point A).
• If an insult occurs, it tends to push the ball out of its
groove or canal and force it up the side of the valley
(point B)
• The magnitude of the loss of velocity will depend on
the severity and duration of the insult.
• Alleviation of the insult will result in a rapid return to
the valley floor at an increased velocity (point C)
• Having reached the floor normal growth velocity is
resumed (point D)
37

38
• Growth chart of a girl who has suffered from celiac
syndrome.
• Condition there is an abnormality of the lining of the gut and
food cannot be absorbed
• Malnourished  growth retardation
• On diagnosis the child is switched to a gluten-free diet
which alleviates the malabsorption.
• Rapid recovery of height velocity
• She demonstrates “complete” catch-up growth within 1-2
years.

• Introduction to the study of human growth and development.
• Curve of human growth has been changing as we evolve
• There is less of environmental constrains on us now, but it is still there
• Infancy and adolescence are the two major stages where adjustment to final size and shape is
still occurring
• More than 50% of infants exhibit either catch-up or catch-down growth, which has direct bearing
on the final size, shape, morbidity, and perhaps mortality
• Timing of the adolescent growth spurt is also important in terms of healthy and successful
survival.
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• We are the survivors and use various survival strategies to survive and propagate our
species.
• One of the most powerful of these strategies is the plasticity of our growth and development.
• In subsequent chapters you will learn how that plasticity is inherited, controlled, and expressed
• It is a fascinating story about the most fundamental biological phenomena of our species.
41

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