Integumentary System

Integumentary System Layers of the Skin: • • • • •

Stratum Basale: the deepest epidermal layer, attached to dermis along a wavy borderline. Stratum Spinosum: several cell layers thick, contains web-like cells called intermediate filaments Stratum Granulosum: consists of three to five cell layers in which drastic change in keratinocyte appear Stratum Lucidum: consists of few rows of clear, flat, and dead keratinocytes, appear as a translucent band above the Stratum Granulosum Stratum Corneum: a broad zone of 20-30 layers thick which accounts for ¾ of the epidermal skin

Cells in Epidermis: • • •

Melanocytes: the spider shaped epithelial cells that synthesize the pigment, melanin Langerhans: arise from bone marrow and migrate to epidermis Merkel Cells: present in the dermal-epidermal junctions, shaped like a spiky hemisphere

Thick vs. Thin Skin: • •

Thick skin: covers the palms, fingertips, and soles of the feet, consisting of five layers Thin skin: covers the rest of body, the stratum lucidum is absent and other strata are thinner

Epidermis: •

Is a keratinized stratifies squamous epithelium consisting of four distinct cell types(Merkel, Langerhans, Melanocytes, and epidermal dendritic cells) and four to five layers(Stratum Basale, Stratum Spinosum, Stratum Granulosum, Stratum Lucidum, and Stratum Corneum)

Dermis: •

Second major skin region, is strong, flexible connective tissue. It cells are usually those found in any connective tissue: fibroblasts, macrophages, and occasional mast cells. Its semi-fluid matrix is heavily embedded with collagen, elastin and reticular fibers.

Skin Color: There are three factors that contribute to skin color: Melanin, Carotene, and Hemoglobin, but only Melanin is made in the skin. •

Melanin, a polymer made of tyrosine amino acids, ranges in color from yellow to reddish-brown to black. Its synthesis depends on an enzyme in melanocytes called tyrosinase, which passes from melanocytes to basal keratinocytes

Glands in Skin: • • • •

Eccrine Glands: are far more abundant on the palms, soles and forehead. Each is a tubular, coiled tubular gland. Apocrine Glands: are largely confined to axillary and anogenital areas. Larger than Eccrine glands and their ducts empty into hair follicles. Ceruminous Glands: are modified apocrine glands found in the lining of the external ear canal. Sebaceous Glands (Oil glands): are simple alveolar glands with little or no visible lumen that are found all over the body except on the palms and soles. Secrete an oily secretion called, sebum

Skin Cancers: Most Common • • •

Basal Cell Carcinoma: is the least malignant and most common skin cancer. Occurs most often on sun-exposed areas of the face and appear as shiny, dome-shaped nodules Squamous Cell Carcinoma: arises from the keratinocytes of the Stratum Spinosum. Appears as a scaly reddened papule that appears on the head and hands Melanoma: cancer of melanocytes, the most dangerous type of skin cancer. Appear spontaneously

Types of Burns: • • •

First-degree burn: only the epidermis is damaged. Symptoms are localized redness, pain and swelling. Second-degree burn: injure the epidermis and the upper region of dermis. Symptoms same as first-degree but blisters may appear Third-degree burn: involve the entire thickness of the skin. Burned area appears graywhite, cherry red, or blackened and with little or no edema.

Rule of Nines: •

A method of estimating the extent of body surface that has been burned in an adult, dividing the body into sections of 9 per cent or multiples of 9 per cent.