Stratum corneum in the context of "Integumentary system"

The integumentary system is the set of organs forming the outermost layer of an animal's body, comprising the skin, hair, scales, feathers, hooves, claws, and nails. It acts as a protective physical barrier between the external environment and the internal environment. Additionally, it maintains water balance, protects the deeper tissues, excretes waste, regulates body temperature, and contains the sensory receptors that detect pain, sensation, pressure, and temperature.

The skin (integument) is a composite organ, made up of at least two major layers of tissue: the outermost epidermis and the inner dermis, which are separated by a basement membrane (comprising basal lamina and reticular lamina). The epidermis comprises five layers: the stratum corneum, stratum granulosum, stratum spinosum and stratum basale. Where the skin is thicker, such as in the palms and soles, there is an extra layer of skin between the stratum corneum and the stratum granulosum known as the stratum lucidum. The dermis comprises two sections, the papillary and reticular layers, and contains connective tissues, blood vessels, glands, follicles, hair roots, sensory nerve endings, and muscular tissue. Between the integument and the deep body musculature there is a transitional subcutaneous zone, the hypodermis.

A stratified squamous epithelium consists of squamous (flattened) epithelial cells arranged in layers upon a basal membrane. Only one layer is in contact with the basement membrane; the other layers adhere to one another to maintain structural integrity. Although this epithelium is referred to as squamous, many cells within the layers may not be flattened; this is due to the convention of naming epithelia according to the cell type at the surface. In the deeper layers, the cells may be columnar or cuboidal. There are no intercellular spaces. This type of epithelium is well suited to areas in the body subject to constant abrasion, as the thickest layers can be sequentially sloughed off and replaced before the basement membrane is exposed. It forms the outermost layer of the skin and the inner lining of the mouth, esophagus and vagina.

In the epidermis of skin in mammals, reptiles, and birds, the layer of keratin in the outer layer of the stratified squamous epithelial surface is named the stratum corneum. Stratum corneum is made up of squamous cells which are keratinized and dead. These are shed periodically.

Sarcoptes scabiei (/sɑːrˈkɒptiːz ˈskeɪbiːaɪ/; sar-KOP-teez SKAY-bee-eye) or the itch mite is a parasitic mite found in all parts of the world that burrows into skin and causes scabies. Humans become infested by Sarcoptes scabiei var. hominis; other mammals can be infested with different varieties of the mite. They include wild and domesticated dogs and cats (in which it is one cause of mange), ungulates, wild boars, bovids, wombats, koalas, and great apes.

The Italian biologists Giovanni Cosimo Bonomo and Diacinto Cestoni showed in the 17th century that scabies is caused by Sarcoptes scabiei; this discovery of the itch mite in 1687 marked scabies as the first disease of humans with a known microscopic causative agent. The disease produces intense, itchy skin rashes when the impregnated female tunnels into the stratum corneum of the skin and deposits eggs in the burrow. The larvae, which hatch in three to 10 days, move about on the skin, moult into a nymphal stage, and then mature into adult mites. The adult mites live three to four weeks in the host's skin.

A cream is a preparation usually for application to the skin. Creams for application to mucous membranes such as those of the rectum or vagina are also used. Creams may be considered pharmaceutical products, since even cosmetic creams are manufactured using techniques developed by pharmacy and unmedicated creams are highly used in a variety of skin conditions (dermatoses). The use of the finger tip unit concept may be helpful in guiding how much topical cream is required to cover different areas.

Creams are semi-solid emulsions of oil and water. They are divided into two types: oil-in-water (O/W) creams which are composed of small droplets of oil dispersed in a continuous water phase, and water-in-oil (W/O) creams which are composed of small droplets of water dispersed in a continuous oily phase. Oil-in-water creams are more comfortable and cosmetically acceptable as they are less greasy and more easily washed off using water. Water-in-oil creams are more difficult to handle but many drugs which are incorporated into creams are hydrophobic and will be released more readily from a water-in-oil cream than an oil-in-water cream. Water-in-oil creams are also more moisturising as they provide an oily barrier which reduces water loss from the stratum corneum, the outermost layer of the skin.