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42 Cards in this Set
- Front
- Back
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What are the two components of skin and what type of tissue are they composed of?
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Epidermis - Epithelial
Dermis and hypdermis - Connective tissue component |
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What are the (4) major functions of skin?
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Protection
Thermoregulation Metabolism Sensation |
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What are the metabolic functions of skin?
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Synthesis of Vitamin D precursor
Stores fat for fatties |
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What are the three layers of the skin?
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Epidermis
Dermis Hypodermis |
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What are the two components of epidermis?
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Stratified Squamous
Basement Membrane |
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What type of tissue is dermis and what is contained in this layer?
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connective tissue
contains: vascular network sensory nerve endings immune cells fibroblasts for wound healing |
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What type of tissue is hypodermis and what is contained in this layer?
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Loose connective tissue
Contains: Extensive adipose deposits aka: superficial fascia |
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What are the (4) glands and/or derivatives of skin that are important?
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Hair - epidermal derivatives that provide warmth and sensory function
Sebaceous glands- secrete an oily substance (sebum) that protects and lubricates the skin. Sweat glands - thermoregulation (eccrine) and other unknown functions (appocrine) Nails - epidermal derivatives on the fingers and toes |
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What are the major cell types of the epidermis?
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Keratinocytes
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What are the 5 layers of cells in epidermis?
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Stratum basale or basal layer
Stratum spinosum or spinous (prickle cell) layer Stratum granulosum or granular layer Stratum lucidum or lucid layer Stratum corneum or cornified layer |
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What does 'desquamates' mean?
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To shed the top layer of skin off
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How long does it take for complete turn over of epidermis?
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2-4 weeks
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Where in the epidermis are the dividing cells located?
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basal layer
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How are cells in the spinous layer attached to each other?
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via desmosomes
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What cell is in the granular layer, and what does this cell secrete?
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keratinocytes that synthesize both cytokeratins and keratohyaline granules
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What do keratohyaline granules contain and what do they do?
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Keratohyaline granules contain filaggrins that assist in the dense packing of the cytokeratin proteins.
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What is the lucid layer?
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Lucid layer is only present in thick skin
No longer has nucleus |
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What are the cells on the most apical layer of epidermis called?
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squames
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What is the most outer layer of skin called and what are the characteristics?
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The outermost layer of skin is the stratum corneum
lost their nuclei and become flattened shells called squames |
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Keratinocytes contain a cytoskeletal structure composed of ______________.
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Cytokeratins (intermediate filaments)
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Describe the structure of cytokeratins:
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Cytokeratins are rod-shaped, largely alpha-helical proteins that assemble into heterodimers containing one Type 1 and one Type 2 keratin.
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What are the main types of cytokeratins in epithelial tissue?
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basal keratinocytes and other epithelial cell types - K5 and K14
In the more differentiated keratinocytes in the skin - replaced by K10 and K1 |
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What are the (3) non-keratinocytes in the epidermis?
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Melanocytes
Langerhans cells Merkel cells |
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Describe the location and function of melanocytes:
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Located in basal layer
Responsible for pigmentation of hair and skin Pigmentation absorbs UV to protect from harmful rays |
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What embryonic tissue are melanocytes derived from?
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Neural Crest
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Where is melanin located after it is manufactured?
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After manufacture, the melanin is transferred to adjacent keratinocytes where they surround the nucleus to shield the DNA
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What are they differing colors of skin due to?
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Color of skin due to the differing size and number of melain granuales
NOT due to differing numbers of melanocytes |
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Where are langerhan cells located and what do they do?
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Located in all layers of the epidermis
Specialized immune cells and may present antigens to active T lymphocytes |
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What are merkel cells?
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Thought to play role in cutaneous sensation
Found in basal layer of epidermis Innervated by long myelinated nerves |
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Where in the skin are most nerve endings found?
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Most are found within dermis and hypodermis
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What is the largest sensory organ in the body?
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skin
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What are evaginations of epidermis into the dermis called?
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Epidermal ridges
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As the epidermis evaginates into the dermis, the dermis has projections into the epidermis. What are they called?
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Dermal papillae
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What are the three major cells types of the dermis?
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Fibroblasts
Mast cells Macrophages |
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What are anastomosing networks?
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Networks that connect arteries and veins
Two distint layers |
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Describe the superficial anastomosis?
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Within the most superficial region of the dermis, vessels enter the dermal papillae to nourish the above epidermis
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Describe the deeper anastomosis:
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A deeper layer of blood vessels is found at the border of the dermis and the hypodermis.
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Why do the dermal vasculature have arteriovenous shunts?
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Important for altering blood flow for thermal regulation
and Involved in inflammation |
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What are the special nerve endings located within the dermis?
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Meissner's corpuscles in the dermal papillae
Pacinian corpuscles that are surrounded by onionlike layers of fibroblasts Ruffini's endings, spindle-shaped receptors Unmyelinated fibers that surround hair follicles |
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Where are meissner's corpuscles located?
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Within dermal papillae
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Describe pacinian corpuscles?
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Surrouned onionlike layers of fibroblasts
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Describe Riffini's endings:
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Spindle-shaped receptors
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