The Integumentary System Ch. 5

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

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