Final answer:
The subject refers to the changes that occur in the integumentary system as a result of aging, leading to a thinner epidermis, weaker dermis, changes in blood vessels, and reduced function of accessory skin structures. These changes cause thinning, sagging, and wrinkling of the skin.
Step-by-step explanation:
As the human body ages, various changes occur that affect the integumentary system. Specifically, aging causes a decrease in cell division within the skin, notably in the stratum basale, contributing to a thinner epidermis. Moreover, aging leads to a decrease in the metabolic activity, which, along with reduced hormonal levels and muscular strength, impacts the skin's ability to maintain its structure and elasticity.
The hypodermis loses its structure as the fat distribution alters, which further contributes to changes in the skin's appearance. The blood vessels also undergo changes; for instance, superficial arteries may constrict, reducing heat loss, while elsewhere blood vessels in the skin dilate to aid in heat dissipation.