Integumentary System

Integumentary System - The Integumentary System Skin...

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Unformatted text preview: The Integumentary System Skin (Integument) Consists of two major regions l Epidermis outermost superficial region l Dermis below the epidermis Integument is separated from the deep fascia by the hypodermis (superficial fascia) 3 Figure 5.1 Epidermis Dermis Hypodermis (superficial fascia) Hair root Hair shaft Pore Dermal papillae (papillary layer of dermis) Meissner's corpuscle Free nerve ending Reticular layer of dermis Sebaceous (oil) gland Arrector pili muscle Sensory nerve fiber Eccrine sweat gland Pacinian corpuscle Artery Vein Adipose tissue Hair follicle receptor (root hair plexus) Hair follicle Eccrine sweat gland Epidermis Composed of keratinized stratified squamous epithelium, consisting of four distinct cell types and four or five layers Outer portion of the skin is exposed to the external environment and functions in protection Cells of the Epidermis Keratinocytes produce the fibrous protein keratin Melanocytes produce the brown pigment melanin Langerhans cells activate the immune system Merkel cells touch receptors l Merkel disc Layers of the Epidermis Layers of the Epidermis Stratum Basale (Basal Layer) l Deepest epidermal layer firmly attached to the dermis l Consists of a single row of the youngest keratinocytes l Cells undergo rapid division, hence its alternate name, stratum germinativum Stratum Spinosum (Prickly Layer) l Many layers of keratinocytes l The keratinocytes contain a weblike system of intermediate filaments attached to desmosomes l Melanin granules and Langerhans cells are abundant in this layer Layers of the Epidermis Stratum Granulosum (Granular Layer) l Thin; three to five cell layers in which drastic changes in keratinocyte appearance occurs l Keratohyaline granules Forms keratin l Lamellated granules Contain water-resistant glycolipids Layers of the Epidermis Stratum Lucidum (Clear Layer) l Thin, transparent band superficial to the stratum granulosum l Consists of a few rows of flat, dead keratinocytes l Present only in thick skin Layers of the Epidermis Stratum Corneum l Outermost layer of keratinized, dead cells l Accounts for three quarters of the epidermal thickness l Functions include: Water-resistance Protection from abrasion and penetration Rendering the body relatively insensitive to biological, chemical, and physical assaults Layers of the Epidermis Dermis...
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This note was uploaded on 01/06/2012 for the course BIOL 2401 taught by Professor Elainefanin during the Fall '11 term at Collins.

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Integumentary System - The Integumentary System Skin...

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