Integumentary System (Skin) Unit 6.3 (6 th Edition) Chapter 7.3 (7 th Edition) 1
Learning Objectives Identify the major components (anatomy) of skin Differentiate between the two types of skin glands Explain the six functions (physiology) of skin Correctly name three abnormal skin colors and identify causes Describe most common skin eruptions Describe the main diseases of the integumentary system (pathophysiology) 2
Skin Anatomy Largest Organ Three Main Layers Epidermis Outermost layer Cells constantly shed/replaced Dermis true skin framework of elastic connective tissue contains blood vessels, nerves, glands, hair follicles Hypodermis (subcutaneous fascia) connects to underlying muscles elastic and connective, fatty tissue 3
Two Types of Glands Sudoriferous Glands sweat glands coiled tubes in dermis open on surface of skin at pores Sebaceous Glands oil glands that open onto hair follicles produce sebum (oil that keeps skin and hair from becoming dry and brittle) sebum is antibacterial and antifungal when an oil gland becomes plugged, accumulation of dirt and oil result in pimple 4
Hair and Nails Hair consists of a root that grows in a hollow tube called a follicle helps protect the body covers all body surfaces except for palms and soles alopecia (baldness/genetic hair loss) Nails protect fingers and toes from injury made of dead, keratinized epidermal epithelial cells cells are packed closely together to form thick surface if lost, nails will regrow if the nail bed is not damaged 5
1 cm 2 of Skin Contains 6
Protection Skin Physiology (Functions) barrier to UV rays protects against invasion of pathogens/germs holds moisture in prevents deeper tissues from drying out Sensory Perception nerves in skin help body respond to pain, pressure, temperature, and touch sensations Body Temperature Regulation blood vessels help body keep/lose heat glands also help cool body through perspiration 7
Storage Skin Physiology Continued skin tissues store fat, sugar, water, vitamins, & salts adipose (fatty) tissue is a source of energy Absorption certain substances can be absorbed through skin transdermal medications for motion sickness, nicotine Excretion skin helps body eliminate salt &small amounts of waste excess water and heat through perspiration Production vitamin D production (matures in liver) 8
Pigmentation (Skin Color) Basic skin color is determined by pigments in epidermis Melanin Brownish/black pigment Varying amounts lead to black, brown, or yellow skin tint absorbs UV light and tans the skin small, concentrated areas of melanin form freckles Carotene yellowish-red pigment also determines skin color Albino person missing color pigments skin has pinkish tint hair is pale yellow or white eyes lack pigment and are red in color 9
Abnormal Skin Colors Erythema reddish color that can be caused by burns also caused by congestion of blood in vessels Jaundice yellow discoloration of skin can indicate bile in blood as result of liver or gallbladder disease occurs along with diseases involving destruction of red blood cells Cyanosis bluish discoloration of skin caused by insufficient oxygen can be associated with heart, lung, and circulatory problems Gray/Brown Discoloration can be caused by chronic poisoning 10
Skin Eruptions Macules flat spots on skin, such as freckles Papules firm, raised area such as pimples also seen in some stages of chickenpox and syphilis Vesicles blisters (fluid-filled sacs) such as those seen in chickenpox Pustules pus-filled sacs such as those seen in acne Crusts areas of dried pub and blood commonly called scabs Wheals itchy, elevated areas with an irregular shape hives and insect bites Ulcer deep loss of skin surface that may extend into dermis (scars) 11
Pathophysiology (Diseases) Acne Vulgaris inflammation of sebaceous (oil) glands Athlete s Foot contagious fungal infection usually affecting feet Skin Cancer basal cell carcinoma, squamous cell carcinoma, and malignant melanoma Dermatitis inflammation of skin in response to irritating substance Eczema noncontagious, inflammatory reaction irritant Impetigo highly contagious skin infection caused by bacteria Psoriasis chronic, noncontagious, inherited disease; scaly Ringworm highly contagious fungal infection of skin/scalp 12