Medic14IntegumentaryCh5

Cutaneous membrane: consists of superficial epithelium or epidermis and underlying connective tissues of the dermis.

Accessory structures: include hair, nails, and a variety of exocrine glands. 

Protection of underlying tissues and organs from in pacts, chemicals and infections.

Temperature maintenance to regulate heat exchange in outside environment.

Synthesis and storage of nutrients such as vitamin D₃ and storage of lipids in adipose tissue.

Sensory reception of touch, pressure, pain, and temperature stimuli and relay that information to nervous system.

Excretion and secretion such as salts, water, organic wastes and breast milk.

Deepest layer of epidermis. Firmly attached to basement membrane by hemi-desmosomes. Forms dermal ridges which extend into dermis and increase area of contact between two ridges so nutrients can be carried into the non-vascular epidermis. 

• Composed of three layers:
• Stratum Spinosum- adds to thickness of epithelium

Stratum Granulosum- produce keratin

Stratum Lucidum- covers stratum granulosum and are packed with keratin

Most superficial layer of epidermis which consists of 15-30 layers of flattened and dead highly keratinized epithelial cells. 

Carotene: orange-yellow pigment that normally accumulates in epidermal cells.

Melanin: brown, yellow-brown, or black pigment produced by melanocytes. Prevents damage from sun by absorbing UV rays before they can reach epidermis and dermis. 

Extremely dangerous cancer in which cancerous melanocytes grow rapidly and metastasize throughout the lymphatic system. 

• Flat spot, color varies from white to brown or from red to purple, diameter less than 1cm.
• 

Superficial papule, diameter more than 1cm, rough texture

Irregular flat macule, diameter greater than 1cm. (Large macule)

Pink, irregular spot varying in size and shape

Elevated firm spot, color varies from brown to red or from pink to purplish red, diameter less than 1cm.

Elevated firm spot, diameter 1-2 cm

Consists of loose connective tissue that supports and nourishes the epidermis. This region contains the capillaries and nerves that supply the surface of the skin.

Deeper layer consists of an interwoven meshwork of dense, irregular connective tissue. Elastic and collagen fibers are present. Elastic fibers provide flexibility, and the collagen limits the flexibility to prevent damage to the tissue.

Protect the scalp from UV light, help cushion light blows, and provide insulating benefits to the skull.

Constriction of arrector pili squeezes sebaceous gland which forces oily secretion into the hair follicle, lubricating the hair and inhibiting the growth of bacteria. 

Apocrine: found in armpits, around nipples and in groin. 

Merocrine: found on rest of body. Also called eccrine glands

1. Bleeding occurs at the site of injury and mast cells in the region trigger an inflammatory response. 

2. After several hours, a scab has formed and cells of the germinative are migrating along the edges of the wound. Phagocytes are removing debris. Clotting around the edges of affected area partially isolates the region.

3. One week after injury, scab has been undermined by epidermal cels migrating over the meshwork produced by fibroblast activity. Phagocytic activity around the site has almost ended, and the fibrin clot is disintegrating. 

4. Several weeks, the scab has shed, and the epidermis is complete. A shallow depression marks the injury site, which will be replaced by scar tissue. 

Combination of blood clot, fibroblasts and an extensive capillary network

Thickened scar tissue most commonly found on upper back, shoulders, anterior chest, and earlobes.