Chapter 5: integumentary system

Structure of the skin Skin is called the cutaneous or integument Skin has two regions The epidermis The dermis

Structure of the skin Epidermis The outer thinner region of the skin Made up of stratified squamous epithelium Divided into the stratum basale and the stratum corneum

Structure of the skin Epidermis Stratum basale- just superior of the dermis Langerhans cells- macrophages found deep in the epidermis that phagocytize microbes and simulate the immune system Melanocytes- specialized cells in the deeper epidermis that produce melanin, responsible for skin color

Structure of the skin Epidermis Stratum corneum- the uppermost layer of the skin Keratin- a fibrous, waterproof cell Mechanical barrier against microbe invasion

Structure of the skin Epidermis

Structure of the skin Dermis A deeper and thicker region Composed of dense irregular connective tissue Dermal papillae causes ridges resulting in fingerprints Contains collagenous and elastic fibers

Structure of the skin Dermis Collagenous fibers prevent skin from being torn and great resistance from over stretching Elastic fibers allow movement but maintain normal skin tension A deeper and thiker region

Structure of the skin Dermis

Structure of the skin Dermis Decubitus ulcers- sore caused by a lacked of blood flow in a particular area that is restricted

Structure of the skin Hypodermis Subcutaneous tissue Lies below the dermis Composed of loose connective tissue including adipose

Accessory Structures Hair Found everywhere on the body except: Palms Soles Lips Nipples

Accessory Structures Hirsutism: excessive body and facial hair

Accessory Structures Alopecia- lack of hair or baldness

Accessory Structures Hair follicles: Are formed from epidermal cells But are located in the dermis Root- portion of the hair found in the follicle Shaft- portion of the hair found above the skin

Accessory Structures Hair follicles: Are formed from epidermal cells But are located in the dermis Root- portion of the hair found in the follicle Shaft- portion of the hair found above the skin

Accessory Structures Hair follicles:

Accessory Structures Nails: From special epithelial cells at the base of the nail called the nail root Nail body is the visible portion of the nail Lunula is the whitish half moon shaped base

Accessory Structures Glands: specialized cells that produce and secrete a substance into ducts

Accessory Structures Sweat gland: Present in all skin Tubular Glands are active under stress

Accessory Structures Sweat gland: Apocrine gland Open into hair follicles In anal region, groin, and armpits Begins secreting at puberty

Accessory Structures Sweat gland: Eccrine glands Open to surface of the skin Active when a person is hot Contains water, salts, urea, and waste

Accessory Structures Sebaceous glands Associate with a hair follicle Secrete sebum : an oil substance Lubricates and waterproofs

Accessory Structures Acne vulgaris Most common Inflammation of the sebaceous glands

Accessory Structures Mammary glands Located in breast Produces milk

Disorders of the skin Athlete’s Foot: fungal infection of the toes and sole

Disorders of the skin Impetigo: highly contagious bacterial infection that results in pustules

Disorders of the skin Psoriasis: chronic condition, the skin is reddish pink patches covered by silver scales

Disorders of the skin Eczema: an inflammation of the skin caused by sensitivity

Disorders of the skin Cyanosis: condition in which the skin has a bluish tint caused by insufficient oxygen in the blood

Disorders of the skin Jaundice: yellowing of the skin caused by an accumulation of bilirubin

Disorders of the skin Albinism: loss of pigment in the skin creating patches of white skin

Disorders of the skin Freckles: melanin concentrated in local areas

Disorders of the skin Dandruff: flaking of the scalp due to accelerated keratinization

Disorders of the skin Uricaria: hive caused by an allergic reaction

Disorders of the skin Nonmelanoma: Basal cell carcinoma Most common Caused from UV exposure Signs are tumors, open sores, reddish patches, smooth growths, shiny bumps or pale marks

Disorders of the skin Nonmelanoma: Basal cell carcinoma

Disorders of the skin Nonmelanoma: Squamous cell carcinoma More like to spread Signs bleeding warts and scabs

Disorders of the skin Nonmelanoma: Squamous cell carcinoma

Disorders of the skin Squamous cell carcinoma Basal cell

Disorders of the skin Melanoma: Starts as a mole Skin around mole turns colors Occurs mostly in fair skinned individuals with a history of sunburns as a child

Disorders of the skin Melanoma:

Disorders of the skin Moles: due to an overgrowth of melanocyte

Disorders of the skin Warts: caused by a virus

Disorders of the skin Burns Caused by Chemicals, Radiation, and Heat Extent of a burn is determined by the “Rule of Nine” Classified by depth of the burn and the extent of the burn

Disorders of the skin First Degree Burns Only the epidermis Reddness and pain, no blisters Subside in 2-3 days

Disorders of the skin Second Degree Burns Only the epidermis and dermis Reddness , pain, and blisters Subside in 10-14 days

Disorders of the skin Third Degree Burns Destroys entire thickness of the skin Leathery surface of brown, black, tan, white or red Destroyed nerves, blood vessels, glands, and follicles

Disorders of the skin Third Degree Burns

Disorders of the skin Fourth Degree Burns Destroyed down to bone Limited chance of survival

Disorders of the skin Major concerns with burns: Fluid loss Heat loss Bacterial infections

Disorders of the skin Autografting Heterografting Graft taken from another part of the patients body Preferred method Heterografting Graft taken from another person

Disorders of the skin Skin Grafts

Effects of aging Epidermis Maintain thickness but cell turnover decreases Skin is looser

Effects of aging Dermis Thinner Flattened Collagenous fibers coarser, thicker, far apart Upper layer lost Decrease in melanocytes

Effects of aging Hypodermis Adipose tissue decreases

Effects of aging Wrinkles caused by: Loose epidermis Fibers are fewer and disorganized Less padding

Homeostasis Functions of the skin Protective function Helps regulate water loss Produces vitamin Regulates body temperature Gathers sensory information

Homeostasis Hypothermia: Body temperature below normal Characterized by Uncontrolled shivering Incoherent speech Lack of coordination Progresses to pulse rate slows hallucinations shallow breathing rigidity

Homeostasis Hyperthermia: Body temperature above normal Heat stroke- body temperature above 110 degrees F w/o sweating Fever