Bones grow through the process of bone cells forming in the growth plates located at the ends of bones. Growth plates allow bones to lengthen until late teens when they fuse shut. Several factors influence bone growth and height, including genes, diet, exercise, lifestyle and sleep. In adulthood, bones continue remodeling through the balanced actions of osteoblasts which build new bone and osteoclasts which break down old bone. Maintaining strong bones requires sufficient calcium, vitamin D, weight-bearing exercise and adequate sleep.
7. The Growing Bone
When you first get
started in your mum’s
womb, your bone
looks like this at about
4 weeks.
The “bone” is mainly a
“lump of cartilage”.
Periosteum grows
around the cartilage
and controls the shape
and thickness of the
bone.
Periosteum
8. The Growing Bone
At about 8 weeks,
bone cells will start
to form in the middle.
The cartilage will
slowly be changed
into bone cells and
grows in length and
thickness.
Bone
Cells
9. The Growing Bone
After birth, the
marrow cavity will
start to form.
Growth plates
(epiphyseal plates),
which are bands of
cartilage, remains to
aid in the growth of
the bone.
Formationofthegrowth
plates
10. The Growing Bone
The bone continues to grow after birth,
which gives rise to the growing height till
adulthood.
12. Feeling Lost?
Not biology class
Only required to have a rough idea
that:
◦ Bone started as one whole piece of
cartilage
◦ After birth, the bone continues to grow at
the Growth Plate (medical name known
as Epiphyseal Plate)
◦ One stops growing when the Growth Plate
is “fused”
14. Question
Which bone in your body determines a
large portion of your height?
◦ Femur (thigh bone) and tibia (shin bone)
15. Growth Plates
Recall:
◦ The presence of the growth plates in the
bone aids the growing of the length of the
bones (eg. Femur and tibia)
Growth plates will not be present in
your bones forever
16. Fusion of Growth Plates
Femur (thigh bone)
◦ Upper end fuses around 18 yrs old
◦ Lower end fuses around 20 yrs old
Tibia (shin bone)
◦ Upper end fuses around 16-18 yrs old
◦ Lower end fuses around 15-17 yrs old
http://www.medhelp.org/posts/Orthopedics/What-bone-age-do-the-growth-plates-completely-close/show/996787
18. Factors Affecting Height
Genes
◦ Determined by parents
Diet
Exercising
Lifestyle
Determined by you
19. Factors: Genes
Height is a polygenic trait
◦ Influenced by several different genes
Estimated height
◦ Boys: (Sum of height of both parents + 13cm) /
2
◦ Girls: (Sum of height of both parents - 13cm) / 2
◦ +/- about 10cm
Genes determines your maximum
possible height You can’t grow taller
than what your body
genes had decided for
you
20. Factors: Diet
Calcium is required for bone growth
Sources:
◦ Dairy products: eg. milk, yoghurt, cheese.
◦ Non dairy products: eg. Bok choy,
almond, orange, seaweed
Source: http://greatist.com/health/18-surprising-dairy-free-sources-
calcium
21. Factors: Diet
𝐷𝑟𝑖𝑛𝑘 𝑚𝑖𝑙𝑘 𝑒𝑣𝑒𝑟𝑦𝑑𝑎𝑦 = 𝑆𝑡𝑟𝑜𝑛𝑔 𝑏𝑜𝑛𝑒𝑠?
Have you ever wonder:
◦ Why I drank so much milk and I never grow
tall?
Reasons are:
◦ Genetic reasons; or
◦ Lack of vitamin D
Vitamin D
◦ Vital to promote the body absorption of the
calcium that we take in
◦ Best source: Sun
◦ Lead an active lifestyle, go under the sun!
22. Factors: Exercising
Increases the rate of the process of
osteoclast and osteoblast (elaborated
later)
◦ In turn increases the speed of bone growth
Weight bearing exercises
◦ Exercises that makes one goes against
gravity
◦ Eg. Running, jumping, climbing of stairs
Helps not only in length growth of bone
◦ Also helps in maintaining strong bones in
adults
◦ Often prescribed for elderlies to maintain
23. Factors: Lifestyle
One important factor that helps in
bone growth, but often neglected by
us.
What is it?
Sleep
24. Factors: Lifestyle
Why sleeping helps in growing taller?
Body undergoes repair and building /
rebuilding when at rest
Similar in bone growth
Recommended at least 8 continuous
hours of sleep
Not to disturb bio-clock to “confuse”
body
◦ i.e. you do not sleep the 8 hours during
daytime
26. Osteoblasts vs. Osteoclasts
In adulthood, bones continue to
undergo process of building and re-
modelling
Why?
◦ Strengthening of bones
◦ Damaging of bones via stress / impact
◦ Need to re-build bones
◦ Similar to maintenance of buildings:
Need to replace older parts with newer parts
27. Osteoblasts vs. Osteoclasts
Osteoblasts
◦ Cells that are responsible to make new
bone cells
Osteoclasts
◦ Cells that are responsible to breakdown
bone cells
Let’s watch a video for better
illustration
29. As we age…
Our bones get
◦ Lighter (less dense)
◦ More brittle
◦ Grow shorter
Common bone issues when old
◦ Osteoporosis
Important to exercise and eat healthily
in order to keep bones healthy
30. Lets Recap!
What is growth plate (epiphyseal
plates)?
Refers to the 2 bands of cartilage at the
end of the bone. It is responsible for the
length growth of long bones before 16-
20 years old.
31. Lets Recap!
What is osteoblasts?
Cells that are responsible to make new
bone cells.
32. Lets Recap!
What is osteoclasts?
Cells that are responsible to make
breakdown bone cells.
33. Lets Recap
What is important in the diet for bone
growth?
Calcium + Vitamin D
Editor's Notes
For the teachers only:
The process of the formation of bone cells in fetus is known as (primary) ossification. It is the degeneration of the cartilage.
Click the diagram to access a webpage with animation on bone growth in young children.