Chapter 6 Integumentary system

Skin

Skin & its appendages

Thin skin, relatively flat organ.

-Superficial, thinner layer

-Epithelial Layer derived from the ectodermal germ layer of the embryo

Dense, vascular connective tissue layer that may avg more than 4 mm in thickness.

The area where the cells of the epidermis meet the the tissue cells of the dermis

Located beneath the dermis , and is rich in fat and loose connective tissues.

Most of what the body surface is covered with.

Hairless skin covering the palms of the hands, fingertips, soles of the feet, and other body areas subject to friction.

In thick skin the underlying dermal papillae are raised in curving parallel to form fingerprints and footprints, that are visible on the overlying epidermis.

Epidermal cell reponsible fro synthesizing keratin.

Tough fibrous protein substance in hair, nails, outer skin cells, and horny tissues.

Cell type in the stratum basale of the skin that produces melanin pigment granules, releasing them to other nearby skin cells.

Also called Langerhan cells, phagocytic cells in the skin. Play a role in immunity.

Layers

'Base layer', Single layer of columnar cells. Deepest layer of the epidermis; cells in this layer are able to reproduce themselves.

'Spiny layer'; layer of the epidermis that is rich in RNA to aid in protein synthesis req'd for keratin production

'Granular layer', layer of which keratinization begins.

Staining granules located within the stratum lucidum; required for surface keratin formation.

'Clear' layer of the epidermis, in thick skin between the stratum granulosum and the stratum corneum.

Substance found in the dying cells of the stratum lucidum; transforms to keratin.

Tough outer layer of the of the epidermis; cells are filled with keratin.

Process by which cells of the stratum corneum become fitted with keratin and move to the surface.

Found everywhere except palms and soles. They secret sebum (oil) and are usuallly associated with hair follicles.

-Function of sebum is to lubricate hair & skin, their secretion is stimulated by hormones, especially adrogens.

Eccrine sweat glands are simple tubular glands important in temp regulation.

Found in ear canals. Secretes cerumen which prevents dryness of the skin of the ear canal, and repels insects.

Composed of dead, keratinized cells and is produced by hair follicles. Arrector pilli muscles are assoc. with ea. hair follicle and is responsible for goose bumps.

Responsible for most of structural strength of the skin.

Cells found in the dermis are, fibroblasts, macrophages, and mast cells.

Dermis contains blood vessels, nerves, hair follicles, arrector pili muscles, and glands.

Reticular Layer

Papillary layer

Comprises abt 80% of the dermis, blends into the hypodermis.

Has more cells, and fewer fibers, and looser. Contains many blood vessels in this layer to support the epidermis.

The papillae of the dermis of thick skin ( on soles and palms ) are in parallel, curving ridges, that shape the epidermis into fingerprints and footprints which inprove grip.

Also known as the subcutaneous (subQ) layer.

Not a part of skin, attaches skin to underlying muscles and is composed of loose connective tissue and fat.

Half of the body's fat is in the subQ layer, variations depend on age, sex, and weight.

Fat in the hypodermis serves as an effective shock asborber