Epidermis

Examples of Epidermis in the following topics:

• Blood Supply to the Epidermis

  • The blood vessels in the dermis provide nourishment and remove waste from its own cells and from the stratum basale of the epidermis.
  • Diffusion provides nourishment and waste removal from the cells of the dermis, as well as for the cells of the epidermis.
  • 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.
  • This is named for its fingerlike projections called papillae, that extend toward the epidermis and contain terminal networks of blood capillaries.

• Structure of the Skin: Epidermis

  • The epidermis is the outermost layer of our skin. 
  • The epidermis is itself divided into at least four separate parts. 
  • It is the layer that’s closest to the blood supply lying underneath the epidermis.  
  • Keratinocytes produce the most important protein of the epidermis. 
  • The newly produced cells push older cells into the upper layers of the epidermis with time. 

• Epidermal Wound Healing

  • Epidermal wound healing refers to the repair of the epidermis in response to wounding.
  • As the epidermis is itself not vascularised—it is receiving blood from the dermis—a clotting and vasoconstrictive response is often not necessary.
  • Since the dermis is intact, local fibroblasts are able to contribute to the formation of a new basement membrane, upon which the epidermis sits.
  • As such, small wounds only in the epidermis typically heal rapidly and are often not observable (e.g., via the formation of scar tissue) within a period of months.

• Development of Vision

  • The eye forms from the neural tube, epidermis, and the periocular mesenchyme, with sequential inductions of tissue during development.
  • The eye develops from the neural tube, the epidermis, and the periocular mesenchyme, which receives contributions from both the neural crest and mesoderm lineages.
  • Epidermis: The optic vesicles come into contact with the epithelum and induce the epidermis.
  • The lens acts as an inducer back to the optic vesicle to transform it into the optic cup and back to the epidermis to transform it into the cornea.

• What is Skin?

  • In order from most superficial to deepest they are the epidermis, dermis, and subcutaneous tissue.
  • The epidermis is a thin layer of skin. 
  • Functions of the epidermis include touch sensation and protection against microorganisms. 
  • This is where the skin’s most important cells, called keratinocytes, are formed before moving up to the surface of the epidermis and being shed into the environment as dead skin cells. 

• Skin and Mucosae (Surface Barriers)

  • The epidermis: comprises the outermost layers of the skin.
  • The basement membrane: a thin sheet of fibers called the basement membrane, that seperates the dermis and epidermis.
  • The dermis: the layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain.
  • The blood vessels in the dermis provide nourishment and waste removal from their own cells as well as for the epidermis.
  • The epidermis continually grows outward to shed old layers of skin and replace them with new layers, while the basement membrane and dermis provide mechanical and chemical support for the epidermis.

• Metabolic Functions

  • The human skin consists of three major layers: the epidermis, dermis, and hypodermis.
  • The epidermis forms the outermost layer, providing the initial barrier to the external environment.
  • Vitamin D is produced in the two innermost strata of the epidermis, the stratum basale and stratum spinosum.

• Blister

  • A blister is a small pocket of fluid in the upper skin layers, forming as fluid collects between the epidermis and the layers beneath.
  • Fluid collects between the epidermis, the upper layer of the skin, and the layers below.
  • Differentiate among the various types of blisters: fluid-filled pockets between epidermis and dermis

• Effects of Aging on the Integumentary System

  • While having some effects on the epidermis, such aging seems to primarily involve the dermis .
  • In younger skin, sun damage will heal faster since the cells in the epidermis have a faster turnover rate, while in the older population the skin becomes thinner and the epidermis turnover rate for cell repair is lower which may result in the dermis layer being damaged.

• Burns

  • Most burns affect only the first two layers of the skin, the epidermis and dermis.
  • First degree burns are limited to the epidermis .