### covering | skin:

Human skin
* Most human skin has layers
  - top layers
* allows the passage of toxic substances.
* can feel infrared radiation.
* comes in pink, yellow, brown, reddish brown, and black.
* contains receptors that inform the brain about mechanical stimuli.
  - remarkable self-healing properties, particularly when only the epidermis is damaged
  - two main layers, the dermis and the epidermis
* is epithelial tissue
  - phospho-lipid deficient
  - relatively water-tight, but fish skin in rather leaky
  - very soft and elastic
* receives no chemical exposure whatsoever.
* sensitive and complex organ utilizing miriad cell processes to function.
* shows high skin color variety from the darkest brown to the lightest pinkish-white hues.
* speedometer for the gases.
* well-designed organ that is an excellent barrier to most agents.

Intact skin
* acts as a barrier to harmful bacteria.
* is considered a primary defense against infection
  - designed as a defense mechanism and is keratinized to decrease permeability
* keeps bacteria out.
* provides an excellent barrier for most biological agents.

Itchy skin
* can result from the stretching of the skin.
* is an early sign of phosphorous building up in the blood stream.

Leathery skin
* Most leathery skin covers bones.
* covered with placoid scales, reduce drag.

Light skin
* absorbs lots of UV, while dark skin absorbs less.
* is most vulnerable because it has less melanin, the pigment that helps prevent burning
  - preferred to dark skin
* makes laser hair removal easier to perform.

Loose skin
* can let the lower eyelid turn outward, causing tearing or eye dryness.
* develops on the neck and head areas as muscle tone declines.
* is separated from underlying tissue and is pulled up and back and excess skin is removed.
* relaxes the pores, thus opening the body to a variety of exogenic pathogens and disease.

Mammalian skin
* has two layers known as the dermis and epidermis.
* includes secretory glands with various functions
  - various secretory glands

Newborn skin
* appears to respond to any injury with an eosinophilic infiltrate.
* is thinner and has less hair than older infants.

Normal skin
* acts as a barrier to prevent water loss and stop skin irritants from penetrating.
* contains cells called melanocytes that produce the brown skin-coloring pigment melanin.
* has an equal balance of water and oil, and medium-sized pores.
* regenerates about every fourteen days.
* sheds whole individual skin cells or small pieces of microscopic whole skin cell.

### covering | skin:

Oily skin
* can be hereditary, which increases the sensitivity of the skin to hormonal changes
  - overly porous
  - become dry, dry skin can become oily
* common problem in patients suffering from acne.
* does keep a lipid or oily film over the face, which does keep it moisturized and supple.
* gives pimples, acne, blackheads and their body odor becomes stronger.
* holds scents much more than dry skin.
* is also the largest contibuter towards acne
  - caused by overactivity of the sebaceous glands
  - characterized by shininess, pimples and blemishes
  - most common among teenagers
  - prone to breakouts of spots and the pores tend to be more visible
  - the main cause of pimples
  - typified by shininess, blemishes and pimples
* reacts well to horsetail , which helps reduce the oil flow.
* tends to attract dirt and dust more readily than dry skin
  - be thick and resilient, while dry skin can be thin and sensitive

Onion skin
* make a rich brown dye.
* produce yellow, walnut hulls produce brown, and pokeberries provide a purple dye.

Orange rind
* Most orange rinds are part of orange.
* is skin

Perilesional skin
* is tested for immunofluoresecence studies.
* shows the presence of intercellular IgG deposition within the epidermis.