Bones

Bones support and protect the body, starting with around 300 at birth, fusing to about 200 in adulthood. They are living organs, constantly renewing every seven years. Bones contain blood vessels, nerve cells, and osteocytes, held by a calcium-phosphorus framework. They adapt to use, growing stronger with activity. Different bone shapes serve various functions, like the spine's support and flexibility or the skull's protection. Bones are vital, diverse, and long-lasting organs.

Describe the structure and function of the spine.

What makes bones unique compared to other organs in the human body?