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59 Cards in this Set
- Front
- Back
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What are the properties of the skin?
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Cosmetic
REgulate temperature Protect from environment Vitamin D metabolism Sensation Immunologic origin |
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Where on the body is the dermis the thickest
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The back
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What type of epithelium is the epidermis?
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keratinizing stratified squamous epithelium
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What are the cell types in the epidermis?*
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Keratinocytes
Melanocytes Langerhans cells Merkel cells |
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What is the layer of cells in the epidermis that divides?
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Keratinocytes
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What are the layers of the keratinocytes?
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Base to top:
Basal Spinous: desmosomes Granular basopihlic, keratohyaline granules Cornified: no organelles |
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What's the turnover time for the skin?
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30 days
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What is the effect of fixing on the epidermis?
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The stratum cornium looks more fenestrated than it really is.
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What is the origin of the melanocytes?
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Neural crest
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What is the function of the melanocytes?
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Create melanin, which protects from UV
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How is melanin distributed throughout thse skin? Where does it go?
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Melanasomes
To the keratinocytes |
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What type of a cell is the melanocyte?
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Dendritic cell
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What layer of cells stains with silver stain? Why? Why is this important
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Basal cell layer
Lots of melanin You need to protect these guys from the sun! |
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Why is darker skin darker?
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Lighter skin: less aggregated MELANOSOMES
Darker skin: melanosomes are more active The number of melanocytes is the same! |
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What enzyme is more active in darkly-skinned people to make their skin darker?
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Tyrosinase
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What is vitiligo?
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When the melanocytes just die off.
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What is the origin of the langerhans cell? What type?
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Bone marrow
Dendritic cells |
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Where are the langerhans cells found?
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Inside the spinous layer
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What is the function of the langerhans cells?
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Skin immune response! - APC
Hypersensitivity reactions (poison ivy) |
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How do you see langerhans cells inside the body?
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You either do a special immunostain or look for the Birbeck granules (it looks like a tennis racket)
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Where are the merkel cells found?
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In the epidermis and dermis
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What is the function of the merkell cells?
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Tactile sensation/slow adapting touch
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Where in the body are the merkel cells found?
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Lower epidermis
Also, in the upper dermis |
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What are the different layers of the basement membranes?
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Laamina lucida
Lamina densa Sublamina densa |
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What attaches the epidermis to the dermis and collagen?
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The anchoring fibrils
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What are the components of the pilosebaceous unit?
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Hair follicle
Sebacious Arector pili |
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What are the three parts of a hair follicle?
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Infundibulum
Isthmus Inferior Also, note that the arrector pilli are on an angle. |
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What are the layers of a hair follicle?
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External (glycogenated) root sheath
Internal root sheath Hair itself |
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What are the different cycles of hair growth?
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Anagen (growth) - 3-4 years, 85-90%
Catagen (involutional) - 3 days, 1% Telogen (resting) - 3 months, 10-14% |
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How can the hair cycle be disrupted?
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You have a stressor, causing less of the hairs to be in the anagenic phase and more in the telogenic phase
More hair comes out! |
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What kind of secretion happens with the sebaceous glands?
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Holocrine secretion
There's so much lipid inside the cells that they explode! |
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Where are sebaceous glands found?
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Everywhere except the palms/soles
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Where are the apocrine sweat glands found?
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Axilla
Groin |
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Other than the axilla and groin, where are apocrine glands found?
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Eyelids
External auditory canal |
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What type of secretion happens in the apocrine glands?
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You have little blips of cytoplasm coming off and then going into the ducts
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Where are the eccrine glands found?
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Palms
SOles Axilla Forehead |
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When you're "sweating" due to exertion, what sweat glands are active?
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Eccrine sweat glands
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What's the structural distance between eccrine and apocrine glands?
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Eccrine connects directly to the surface (via straight duct)
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What are the layers of the dermis?
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Papillary dermis
Reticular dermis |
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What are the different components of the dermis?
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Colagen
Elastic tissue Ground substance Fibroblasts, mast cells, dermal dendrocytes |
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What cells synthesize collagen in the dermis?
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Fibroblasts
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What are the types of collagen found in the skin?
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Type I: most abundant, coiled; reticular dermis
Type III: Fine, loosely arranged; papillary dermis Type IV, VII: BM (IV: basal lamina, VII: anchoring fibrils) |
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What cells make elastic tissue?
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Fibroblasts
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What is the function of the elastic tissue?
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Elasticity of the skin
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What are the different proteins in the elastic tissue?
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Elastin
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What amino acids are unique to elastic tissue?
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Desmosine
Isodesmosine |
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What happens to the elastic tissue as you age?
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They get damaged!!!
You get wrinkles! |
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What cells make the ground substance?
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Fibroblasts
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What are the components of the ground substance?
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Fibronectin
Glycosaminoglycans |
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What do fibroblasts produce?
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Collagen
Elastin Ground substance |
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What part of the dermis are thicker?
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Reticular
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What type of collagen is in the reticular dermis?
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Type I collagen
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What are the types of nerves in the skin?
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Free nerve endings
Meissner's corpuscle Merkel cell complex Pacinian corpuscle |
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What are the functions of the free nerve endings?
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Temperature
Pain PUritis |
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What are the functions of the Meissner's corpuscle?
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Fine touch
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What are the functions of the Merkel cell complex?
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Slow adapting touch
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What are the functions of the Pacinian corpuscle?
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Deep pressure
Vibration |
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Where are Meissner's corpuscles located in high concentrations?
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Fingertips, etc.
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What do pacinian corpuscles look like?
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ONIONS!
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