Intrinsic and extrinsic aging
Encyclopedia
Intrinsic aging and Extrinsic aging are terms used to describe cutaneous aging of the skin
and other parts of the integumentary system
, which while having epidermal concomitants, seems to primarily involve the dermis
. Intrinsic aging is influenced by internal physiological factors alone, and extrinsic aging by many external factors. Intrinsic aging is also called chronologic aging, and extrinsic aging is most often referred to as photoaging.
and elastin
in the dermis.
Extrinsic aging of skin is a distinctive declination process caused by external factors which include ultra-violet radiation, cigarette smoking, air pollution, among others. Of all extrinsic causes, radiation from sunlight has the most widespread documentation of its negative effects on the skin. Because of this, extrinsic aging is often referred to as photoaging. Photoaging
may be defined as skin changes caused by chronic exposure to UV light. Photodamage, implies changes beyond those associated with aging alone, defined as cutaneous damage caused by chronic exposure to solar radiation and is associated with emergence of neoplastic lesions.
Skin
-Dermis:The dermis is the layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. The dermis is tightly connected to the epidermis by a basement membrane. It also harbors many Mechanoreceptors that provide the sense of touch and heat...
and other parts of the integumentary system
Integumentary system
The integumentary system is the organ system that protects the body from damage, comprising the skin and its appendages...
, which while having epidermal concomitants, seems to primarily involve the dermis
Dermis
The dermis is a layer of skin between the epidermis and subcutaneous tissues, and is composed of two layers, the papillary and reticular dermis...
. Intrinsic aging is influenced by internal physiological factors alone, and extrinsic aging by many external factors. Intrinsic aging is also called chronologic aging, and extrinsic aging is most often referred to as photoaging.
Causes and Effects
The effects of intrinsic aging are caused primarily by internal factors alone. It is sometimes referred to as chronological aging and is an inherent degenerative process due to declining physiologic functions and capacities. Such an aging process may include qualitative and quantitative changes and includes diminished or defective synthesis of collagenCollagen
Collagen is a group of naturally occurring proteins found in animals, especially in the flesh and connective tissues of mammals. It is the main component of connective tissue, and is the most abundant protein in mammals, making up about 25% to 35% of the whole-body protein content...
and elastin
Elastin
Elastin is a protein in connective tissue that is elastic and allows many tissues in the body to resume their shape after stretching or contracting. Elastin helps skin to return to its original position when it is poked or pinched. Elastin is also an important load-bearing tissue in the bodies of...
in the dermis.
Extrinsic aging of skin is a distinctive declination process caused by external factors which include ultra-violet radiation, cigarette smoking, air pollution, among others. Of all extrinsic causes, radiation from sunlight has the most widespread documentation of its negative effects on the skin. Because of this, extrinsic aging is often referred to as photoaging. Photoaging
Photoaging
Photoaging or photoageing is a term used for the characteristic changes induced by chronic UVA and UVB exposure. Tretinoin is the best studied retinoid in the treatment of photoaging...
may be defined as skin changes caused by chronic exposure to UV light. Photodamage, implies changes beyond those associated with aging alone, defined as cutaneous damage caused by chronic exposure to solar radiation and is associated with emergence of neoplastic lesions.