Integument PA 481 C Anatomy & Physiology Dr. Tony Serino

Integument System: Skin Functions: –Protection Germ and water proof barrier, abrasion resistant –Sensory Organ in first contact with external environment –Homeostasis Thermoregulation (excretory), Ca ++ balance –Communication Muscle attachment Secretes phermones –for communicating

Layers of the Skin Epidermis –Outermost layer, composed of keratinocytes Dermis –Thickest layer, composed of many connective tissues and is the site for many glands and other epidermal derivatives Subcutaneous layer (Hypodermis) –Attaches skin to underlying structures

Epidermis Composed of 4-5 layers of keratinocytes which is formed into a stratified squamous epithelium Main gene product is keratin, a water insoluble protein Some cells from the dermis invade and reside in the epidermis’ deepest layers including Merkel cells, Langerhans cells, and melanocytes (basale)

Melanocytes: produce melanin

Wine Stain –birth mark due to overgrowth of blood vessels in skin Tattoo –voluntary injection of ink below epidermis Acne Rosacea – permanent reddening of skin on face, especially. Maybe due to drug interactions, alcohol, spicy foods, TB, syphilis, or lupus Other Pigmentations

Dermis Composed of a mixture of CT, including dense irregular, loose areolar, elastic, and adipose tissues Divided into 2 regions: –Papillary layer: region of dermal papillae –Reticular layer: thickest layer of skin, provides strength, elasticity and space for glands, hair follicles, etc. –creates tension lines of skin Papillary Region Reticular Region Hypodermis

Dermal Papillae: arranged into regular patterns in palms and soles

Burns 1st 2nd 3rd

Skin Cancers Basal cell carcinoma Squamous cell carcinoma Melanoma

Epidermal Derivatives Structures which grow from the epidermis but reside mostly in the dermis Nails, Hair, and glands of skin

Nail Nail Matrix Nail Fold Nail Bed

Hair Hair Bulb Hair shaft Sebaceous gland Hair root Hair papilla

Epidermal Glands Sebaceous glands –secretes sebum (an oil) used to maintain skin and hair moisture Ceruminous glands –secretes cerumen (ear wax), used to keep foreign objects out of ear Sudoriferous (sweat) glands –secrete sweat (water with some salts), used in heat regulation and in phermone secretion: two types: Apocrine and Eccrine (Merocrine) Mammary Glands –secrete milk

Sweat Glands

Breast

Milk Line

Breast Cancer and Mammograms NormalTumor

Mammary gland