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18 Cards in this Set
- Front
- Back
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Describe the Dermis. (2) |
* Second major skin region * Strong, flexible CT |
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What cells are contained in the Dermis? (4) |
* Fibroblasts * Macrophages * Occasional mast cells * WBC |
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Describe the matrix of the Dermis. (4) |
* Semifluid matrix embedded with fibers * Binds the entire body together like a body stocking * Has a rich supply of blood vessels, nerve fibers and lymphatic vessels * Creates: hair follicles, oil & sweat glands |
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What are the two layers in the Dermis? |
* Papillary layer * Reticular layer |
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What is the Papillary layer? (8) |
* Thin superficial layer * Areolar CT * Fine interlacing of collagen & elastic fibers with small blood vessels * Looseness allows phagocytes and defensive cells to wander freely to look for bacteria that have breached the skin * Has Dermal Papillae: peg like projections from its surface * Contains capillary loops * Free nerve endings and touch receptors = Meissner's Corpuscles * Friction ridges (dermal & epidermal ridges = fingerprints) for gripping |
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What is the Reticular layer? (4) |
* 80% of the thickness of the dermis * Coarse, irregularly arranged * Dense CT * ECM: Pockets of adipose cells and thick bundles of interlacing collagen fibers, parallel to the skin surface, give the skin strength & resiliency |
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What is Melanin? (3) |
* Melanin is a polymer made of tyrosine amino acids that range in color from reddish yellow to brownish black * Found in the stratum basale & spinosum * All races have about the same # of melanocytes, but the amount of melanin varies |
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What determines Skin color? (5) |
* Skin color is determined by the kind and amount of melanin made and retained. * Brown = melanin * Yellow = carotene * Pink = hemoglobin * More sun = more melanin = darker skin |
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What are the accessory structures associated with skin? (3) |
* Hair * Nails * Glands |
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Describe Hair. (2) |
* Flexible strands produced by hair follicles * Consists of dead, keratinized cells |
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What are the functions of Hair? (5) |
* Keeps us warm * Senses insects on the skin before they can bite * Scalp hair protects the head from trauma, heat loss and sunlight * Eyelashes shield the eyes * Nose hairs filter particles from the air |
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Describe Nails. |
Scale-like modification of the epidermis that forms a clear protective covering on the dorsal surface of the distal part of the finger or toe |
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Describe Sweat Glands. (3) |
* Eccrine & Apocrine * Specialized cells that contract when stimulated by the nervous system * The contraction forces sweat into and through the glands duct system to the skin surface |
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What are the functions of Sweat Glands? (2) |
* Prevents the body from overheating * Cold sweat: fright or nervousness |
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Describe Eccrine glands. (3) |
* Simple, coiled, tubular glands * Sweat: 99% water with some salt * Sweat is acidic (pH 4-6) |
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Describe Apocrine (or Merocrine) glands. (6) |
* Larger than Eccrine glands * Ducts empty into hair follicles * Sweat + fatty substances + proteins * Viscous & can be milky or yellowed * No odor (but when mixed with bacteria on the skin surface = body odor) * Begins functioning at puberty, with hormones |
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Describe Ceruminous Glands. (3) |
* Found in the external ear canal * Produces ear wax * Deters insects & foreign material from entering the ear |
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Describe Sebaceous glands. (4) |
* Simple, branched, Alveolar glands * Found everywhere except soles/palms * Develop as outgrowths of hair follicles and occasionally pores * Creates pimples |
