Download Bone growth

A LESSON FOR PARENTS
By Matt Cortale, Casey Dillon, Ian Doyle
What is the Function of Bone?
•
Support, Movement & Protection!
• gives shape to head, etc.
• supports body’s weight
• protects lungs, etc.
• bones and muscles interact
• when limbs or body parts move
Bone Growth In The Fetus
Intramembranous Bones In The Fetus
The flat bones of the skull
are INTRAMEMBRANOUS
BONES.
 During their development,
unspecialized connective
tissue appears at the sites
of future bones.
 Dense blood vessels form
and supply the connective
tissue with blood.
 Eventually, through a
process called
intramembranous
ossification, this connective
tissue forms flat bone.

Endochondral Bones In The Fetus
Most bones of the skeleton
are ENDOCHONDRAL
BONES.
 They develop from masses
of hyaline cartilage shaped
like future bony structures.
 These cartilaginous models
grow rapidly for a time and
then begin to change
extensively.
 Eventually, through a
process called
endochondral ossification,
this hyaline cartilage forms
endochondral bones.

Endochondral Bone Development
Major Stages (a-d fetal), (e child), (f adult)
Fetal Stage


In the region known
as the primary
ossification center,
bony tissue begins
to replace hyaline
cartilage.
The epiphyses
remain cartilaginous
and continue to
grow into secondary
ossification centers.
Child Stage
Here, in the child stage of long
bone, we see the formation of
the epiphyseal plates or disks.
 These plates lie between the
primary and secondary
ossification centers of the long
bone.
 Long bone continues to
lengthen while the epiphyseal
plates are active.
 However, once the epiphyseal
plates ossify, lengthening is no
longer possible at that end of
the bone.

Adult Stage


A developing bone
thickens as compact
bone just beneath the
periosteum or outer
layer of bone.
The bone in the
central regions of the
epiphysis and
diaphysis remains
spongy, and hyaline
cartilage on the end of
epiphyses persists
throughout life.
What Do Bones Need to Grow?
Vitamin A supports bone development
 Vitamin C strengthens bone
 Vitamin D supports bone structure
 Bones, like muscles, need physical
stress to break down and cause the
bone to regenerate healthier cells

Vitamins

Vitamin A
 Necessary for osteoblast and osteoclast
 Deficiency may retard bone development

Vitamin C
 Required for collagen synthesis
 Deficiency results in slender, fragile bones

Vitamin D
 Necessary for calcium absorption
Hormones

Growth Hormone
 Stimulates division of cartilage cells
 Pituitary dwarfism- bones fail to develop
normally and child is very short. This is due
to lack of growth hormone.
 Pituitary gigantism- excess growth hormone
is released, height may exceed 8 ft.
 Acromegaly- In adults, excess growth
hormone causes enlarged hands, feet, and
jaw.
Hormones (cont’d)

Sex Hormones
 In males testosterone, in females estrogen
 Cause long bones to grow considerably.
 Become abundant at puberty
 Estrogen typically has a stronger effect on
epiphyseal plates which is why females
reach their maximum growth earlier than
males.
Hormones (cont’d)

Thyroid Hormone
 Stimulates replacement of cartilage with
bone tissue
 Increases cellular metabolism
 Stimulates osteoblast activity
Male vs Female Growth
Females tend to hit puberty earlier than
boys. This is why girls are usually taller
than boys in elementary school. Girls
usually stop growing at the age of 17.
 Males develop longer and hit puberty at an
older age. This is why men tend to be
taller than women in adulthood. Men
usually stop growing by the age of 18 but
can grow up to the age of 25.
 As our body ages, both sexes decrease in
heighth after about age thirty.

Life-Span Bone Growth
Puberty age 12
Age 30
Male Skeletor
Puberty age 10
Age 30
Female Skeletor
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