Compare a young adult skeleton to that of an extremely aged person relative to bone mass in general and the bony structure of the skull, thorax, and vertebral column in particular.

Name: Human Anatomy & Physiology
Author: Marieb, Hoehn
ISBN: 9780136874034

Verified step by step guidance

Step 1: Understand the general changes in bone mass with aging. Recognize that bone mass typically decreases in an extremely aged person compared to a young adult due to factors like reduced osteoblast activity and increased bone resorption, leading to conditions such as osteoporosis.

Step 2: Examine the skull structure differences. In a young adult, the skull bones are dense and well-fused, while in an aged person, there may be thinning of the cranial bones and possible enlargement of cranial sutures due to bone loss.

Step 3: Analyze changes in the thorax. The ribs and sternum in a young adult are robust and maintain their shape, whereas in an aged individual, the bones may become more brittle and less dense, potentially leading to a decreased thoracic cavity size and reduced flexibility.

Step 4: Investigate alterations in the vertebral column. Young adults have vertebrae with strong, dense bone and well-maintained intervertebral discs, while aged individuals often experience vertebral bone loss, compression fractures, and disc degeneration, resulting in decreased height and possible spinal curvature changes.

Step 5: Summarize how these structural changes affect overall skeletal function, including increased fracture risk, reduced mobility, and changes in posture, emphasizing the importance of bone health maintenance throughout life.

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Bone Mass Changes with Age

Bone mass typically peaks in young adulthood and declines with age due to decreased bone formation and increased resorption. This leads to conditions like osteoporosis, where bones become more fragile and less dense, affecting overall skeletal strength.

Age-Related Structural Changes in the Skull

In aged individuals, the skull may show thinning of the cranial bones and loss of bone density, especially in areas like the frontal and parietal bones. Sutures may become less distinct, and some bones can become more brittle, impacting protection of the brain.

Degenerative Changes in the Thorax and Vertebral Column

With aging, the thoracic cage often becomes more rigid due to calcification of costal cartilages, while vertebral bodies lose height and density, leading to curvature changes like kyphosis. Intervertebral discs also degenerate, contributing to reduced flexibility and height.

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