Bones Aren't Dead: The Living System Holding You Together
- medyouthalliance
- 5 days ago
- 2 min read
Written By Emman Allahgul
Med Youth Alliance | January 2026
We often think and learn bones as something hard, stable and structured. That is very wrong. Bones are actually living tissue that are constantly active, growing, repairing damage and reshaping themselves to maintain their strength.
How bones grow, repair and remodel
Growth:
In early development, a foetus' skeletal system is made from only cartilage, which later hardens during the process of Ossification (process from which bone tissue is made from the hardening of cartilage). This process lasts throughout childhood.
1) Cartilage model of the bone is formed (continues growing as Ossification takes place)
2) Ossification begins at the primary ossification centre in the middle of the bone (a point in the cartilage that develops during foetal development)
3) Ossification then takes place in the secondary ossification centre (at the end of the bones)
4) The medullary cavity forms and will contain red bone marrow
5) Bone growth ends as areas of ossification meet at epiphyseal plates
Repair:
Fractures take about 6-8 weeks to repair, but sometimes longer in larger/elderly bones
1) A haematoma is formed at the site of fracture (blood vessels that have been ruptured, causing a blood filled vessel)
2) A cartilage callus forms, acting as a splint to the broken bone
3) A bony callus forms, replacing the cartilage with a callus made of spongy bone
4) The bony callus remodels in response to the stress put onto it, forming a strong, permanent patch at the site of fracture
Remodel:
A lifelong process involving the removal of mature bone tissue from the skeletal system and new bone tissue being formed
Part of the repair and formation of bones
Role of osteoblasts and osteoclasts:
Osteoblasts:
Grow new bones (bone formation)
Reshape bones to help them change as you grow (remodelling)
Heal damage/broken bones
Triggered by chemical reactions/hormones, secreting the bone matrix which consists of proteins for bone health like collagen mixed with minerals like calcium and phosphate
Move and secrete bone matrix in areas that need growth, strength or repair
After, they can differentiate into osteocytes and become part of the bone or die
Osteoclasts:
Dissolve/break down old or damaged bones by releasing enzymes, making space for osteoblasts to help make new bone tissue
Only target specific areas which need growth/repair
Why fractures heal faster in younger people
As we age, our osteoblasts (building) cannot keep up with the activity of our osteoclasts (removing), hence more bone is being removed compared to being made
Unlike in older people, children's bones behave like they are always growing, with constant osteoblasts forming new bone tissue
In conclusion, despite their strong structure, the tissue in bones move to aid with movement of the body, ensuring that bone tissue is made, repaired, grown and remodelled. Through the continuous work of osteoblasts and osteoclasts, bones are able to remain strong and heal after injury.
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