Cellular aspect of aging
Connective tissues, which are responsible for supporting and binding tissues and organs, in the body change by becoming stiffer. As a result, the organs, blood vessels, and airways become more rigid. This can disrupt the delivery of oxygen and nutrients through the body and in the removal of cellular waste.
Muscle tissues also lose their mass over time, a process known as atrophy, which typically occurs when the tissues aren’t used as often.
Generally, the most important body changes that occur with aging involve the heart, the lungs, and the kidneys. These are typically related to the loss of their ability adapt to or reverse changes in the body. For example, the heart has a “reserve ability” to pump out more blood when necessary. But as patients develop atherosclerosis, the heart will have to work harder. As a result, it slowly losing its ability to compensate for changes in blood pressure.