The Integumentary System

Ch. 6

Objectives

• Identify various parts of the integument

• Know the functions of the integumentary system

• Know the structural composition of hair and nails

• Understand how skin disorders like cancer and burns are classified and what occurs during these disorders

The Integumentary System

• Includes the skin (integument) and the accessory organs found within the skin

Skin: Integumentary System

• Functions: prevent dehydration, protect from injury, serve as defense against microorganisms, regulate body temperature, make vitamin D, provide sensation, nonverbal communication

• Structure:– Epidermis: outer layer, stratified squamous epithelial

cells, no blood vessels, specialized keratinocytes and melanocytes

– Dermis: deeper layer, support tissues, fibers

Skin: Integumentary System

Epidermis

• Keratinized stratified squamous epithelium

• Cell types– Regenerative stem cells– Keratinocytes– Melanocytes– Tactile cells– Dendritic cells

Layers of the Epidermis• From deep out– Stratum basale

– Stratum spinosum

– Stratum granulosum• Keratohyaline granules

– filaggrin• Lamellated granules

– Stratum lucidum• Thick skin only

– Stratum corneum

pgbeautygroomingscience.com

Skin Histology

nku.edu

Skin Color

• Melanin– The more produced, the darker the color

• Hemoglobin– Reddish – pink skin tones

• Carotene– Yellow hue to skin– Concentrates in stratum corneum

Diagnostic Abnormal Skin Color• Cyanosis

– Skin has a blue appearance• Due to lack of oxygenated blood

• Albinism– Lack of melanin

• Results from inheritance of nonfunctional tyrosinase

• Jaundice– Yellowing of skin and whites of eyes

• Due to the inefficient removal of bilirubin

• Hematoma– Bruise

• Mass of clotted blood

• Erythema– Abnormal redness of the skin sciencephoto.com

Skin Markings

• Friction ridges

• Flexion lines

• Freckles and moles– Melanocyte aggregates

• Hemangiomas– Benign blood capillary tumors

skinsight.com

Dermis

• Connective tissue layer deep to the epidermis– Attached to the epidermis via dermal papillae• Interlocking arrangement with epidermal ridges

• Two layers– Papillary• Areolar

– Reticular• Dense irregular

Accessory Structures of Dermis

• Hair: shaft, follicle

• Smooth muscle: attached to hair follicle, raises hair to upright position

• Oil glands/sebaceous glands: secretion moistens and softens skin

Accessory Structures of Dermis (cont.)• Sweat glands: secrete sweat, help in

temperature regulation– Apocrine and merocrine

• Blood vessels: supply nutrients, remove waste, assist in temperature regulation

• Sensory nerve endings: for heat, cold, touch, deep pressure, vibration

Dermis

healthguide.howstuffworks.com

Hypodermis

• Binds skin to underlying tissue

• Functions as padding and insulation– Subcutaneous fat

• Readily absorbs drugs given by hypodermic injection– Highly vascular

Hair

• Pili (sing. Pilus) are composed of hard, dead keratinized cells

• Grow from a follicle that is typically found in the dermis

• Hair divided into three zones– Bulb which lies in the follicle– Root– Shaft

keratin.com

Nails

• Scale-like modifications of the epidermis (startum corneum)

• Dead cells full of parallel hard keratin

emedicinehealth.com

Skin Disorders

• Skin Cancer– One of the most prevalent cancers– UV radiation damages cells

– Three types • Basal cell carcinoma

– Most common, stratum basale• Squamous cell carcinoma

– Stratum spinosum• Malignant melanoma

– Most deadly, melanocytes

metrohealth.org

Burns• Classified based on depth of tissue involvement– First degree

• Epidermis – Red, slight swelling

– Second degree• Epidermis and into part of the dermis

– Red to white, more painful– Regeneration of epidermis possible

– Third degree• Full-thickness, completely through dermis and beyond

– Tan to brown, danger of fluid loss and infection– Generally require skin grafts to replace dermis and epidermis

burn-recovery.org