Bone tissue structure changes with increasing age like
any other tissue of human body in which changes do occurs with increasing age.
Wear tear occurs to different tissues with increasing age and they also get
repaired up by healing mechanism of human body. But in old age healing
mechanism get a little bit slower which is responsible for slow healing of
tissues in old age.
The same applies to bone tissue. In childhood and
adolescent age bone tissue forms easily, fastly and also gets repaired up fastly.
But with increasing age repair mechanism gets a little bit slower.
In childhood and adolescent age, rate at which new bone tissue is formed by
osteoblasts is much faster than the rate at which old worn out bone tissue is
destructed by osteoclasts. Healing and repair of bone tissue requires formation
of new bone tissue and removal of old worn out tissue. As the formation of new
bone tissue is much faster in childhood and adolescent age, therefore healing
occurs much fastly. And as the new bone tissue is formed much fastly by
osteoblasts than the bone tissue lost by osteoclasts, therefore, bones are much
stronger, thicker, hard and healthy and strengthened in this age. More
strengthened and strong bones mean bones less prone to breakage that means less
liable to fractures. As the healing occurs much faster in this age, therefore,
fractures, if any how, if any occur to bones in this age, then healing occurs rapidly
and fractures gets healed fastly.
But as age increases further from
childhood and adolescent age to adulthood, further changes occur in bone
tissue structure and its functioning process. As young
adult age comes, rate of new bone tissue
formation which was faster in childhood and adolescent age now becomes
equal to rate at which old worn out tissue is destructed by osteoclasts. Now,
as both rates of new bone tissue formation and old bone tissue destruction are
same, therefore, healing is still going on normal pace though not that fastly,
as in childhood but still at normal speed and bones are still that much
stronger and strengthened as in childhood and adolescent age.
But as age increases from
young age to middle age and approaches middle
age, especially in women after menopause, at that age female hormones
like estrogen which are responsible for healthy functioning of bone tissue
cells starts getting decreased in middle age and get stopped suddenly in women
after menopause and result is, that rate at which
new bone tissue get formed by osteoblasts becomes slower than rate at
which the old bone tissue gets destructed by osteoclasts and this result in
decrease in bone tissue mass.
In old age, rate of new bone tissue
formation by osteoblasts gets much slower
than rate at which old bone tissue get destructed, that is more bone tissue is lost than is formed by
osteoblasts. That is, more bone tissue loss occurs
in old age and that result in more weaker, porous and unhealthy bones. Now, as female bones are much smaller and less massive than men’s
bones, so they are more prone to osteoporosis and as female hormones
like estrogen which are responsible for normal and healthy functioning of bone
cells get stopped suddenly in women after
menopause, therefore, bone tissue loss occurs much earlier in women and
much fastly than men whose hormones starts getting finishing gradually and much
slowly than women’s hormones, therefore, bone tissue loss occurs much slowly
and gradually in men and as their bones are bigger and massive than women’s bones,
therefore, their bone tissue loss takes more time than it take in women’s bone
tissue mass loss to occur.
This was one way loss of bone tissue mass occurs with increasing age. The other way, the loss of bone tissue mass occurs is by demineralization, that is, through the loss of calcium and other minerals from bone extracellular matrix which occurs with increasing age. Demineralization starts at age of thirty in females and get speeder up with age of forty five when females hormones like estrogens which are responsible for adequate deposition of calcium and other minerals required by bone extracellular matrix starts getting decreasing in females and get stopped suddenly after menopause and about thirty percent of calcium in bones is lost by age of seventy.
Once bone mass loss starts in females about eight
percent of bone mass loss occurs in every ten years. Whereas in males, calcium
loss starts occurring after the age of sixty and that too at the rate of three
percent of bone mass loss in every ten years which is much lesser than bone
mass loss of females which is eight percent bone mass loss every ten years.
This is also the reason why osteoporosis occurs
much earlier in women than men. As bone tissue loss, whether in terms of
bone tissue cells or bone extracellular matrix loss by loss of bone tissue
minerals occurs much earlier in females than males which are responsible for early
onset of osteoporosis in females and also higher incidence of osteoporosis
among females.
With increasing age, in old age there occurs slower
synthesis of collagen fiber, due to diminished production of human growth
hormone. There occurs also slower protein synthesis. Rate of protein synthesis
get decreased. Collagen fibers which forms the major organic part of bone
extracellular matrix and also gives bone its tensile strength. Slower rate of synthesis
of collagen fiber in old age result in loss of tensile strength of bone which
ultimately result in brittle bones which are more prone to fractures and get
fractured easily from slight jerk in old age. In addition to increasing tendency
of bones to get fractured easily, loss of bone mass and loss of tensile
strength in old age also deforms your bones, make human bones liable to suffer
from bone pain and loss of human body height and loss of teeth from mouth and
also osteoporosis of bones.
Do you know-