Download - The Integumentary System
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