Integumentary System

(Skin)

Unit 6.3 (6th Edition)

Chapter 7.3 (7th 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 tissue3

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 pimple4

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 damaged5

1 cm2 of Skin Contains

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Skin Physiology (Functions)

• Protection

– 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

Skin Physiology Continued

• Storage

– 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)

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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 color9

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