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190 Cards in this Set
- Front
- Back
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What are the 2 main components of the Lamina Lucida?
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1) Hemidesmosome Complex
2) Anchoring Filaments |
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What are the 4 components of the hemidesmosome complex?
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1) BPAg1
2) BPAg2 3) Plectin 4) a6b4 Integrins |
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Is BPAg1 intracellular, extracellular or a transmembrane protein?
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BPAg1 is an Intracellular protein
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What is the molecular weight of BPAg1?
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230kD
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Is BPAg1 part of the Plakin or Plectin family?
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BPAg1 is in the Plakin family
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What function does BPAg1 serve as part of the hemidesmosome?
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Attaches intermediate filaments to the hemidesmosome plaque
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Is BPAg2 intracellular, extracellular or a transmembrane protein?
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BPAg2 is a transmembrane protein
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What is the molecular weight of BPAg2 ?
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180kD
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What 3 proteins does BPAg2 interact with intracellularly?
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1) BPI
2) b4 Integrin 3) Plectin |
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What 2 proteins does the NC-16 domain of BPAg2 interact with extracellularly?
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1) a6 Integrin
2) Laminin 5 |
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What 2 components of the hemidesmosomal complex are part of the Plakin family?
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1) BPAg1
2) Plectin |
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What is the function of Plectin in the hemidesmosomal complex?
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Plectin links intermediate filaments to the plasma membrane
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What is the function of a6b4 integrin in the hemidesmosomal complex?
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a6b4 integrin, links the intermediate filaments to the extracellular matrix
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Name the 4 different anchoring filaments
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1) Laminin 5
2) Uncein 3) Fibronectin 4) Nidogen (aka Entactin) |
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What does Laminin 5 do?
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Binds to a6b4 integrin
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What does Nidogen (aka Entactin) do?
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Binds Laminin 1
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What are the 2 main components of the Lamina Densa?
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1) Type 4 Collagen
2) Heparin sulfate proteoglycan |
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What are the 2 types of anchoring proteins found in the Sublamina Densa?
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1) Anchoring fibrils
2) Acnhoring plaques |
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What is the main anchoring fibril?
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Collagen 7
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What are the 2 main anchoring plaques?
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1) Collagen 4
2) Laminin 5 |
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What 2 growth factors stimulate Melanocytes?
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1) Beta-FGF
2) TGF-Alpha |
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What 3 factors inhibit Melanocytes?
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1) IL-1
2) IL-6 3) TGF-Beta |
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Tyrosine is converted to what in the synthesis of melanin?
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Tyrosine➜DOPA➜DOPA quinine ➜melanin
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What enzyme catalyzes the conversion of Tyrosine to Melanin?
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Tyrosinase
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In dark skinned people, are melanosomes larger or smaller?
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Dark skinned people have larger melanosomes
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Do dark skinned people have more, less or the same number of melanosomes as white people?
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Dark skinned people have more melanosomes
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Do the melanosomes in dark skinned people have more, less or the same amount of melanin as white people?
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Dark skinned people have more melanin in each melanosome
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Do you find free nerve endings in the epidermis, sub epidermis or dermis?
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Free nerve endings are found subepidermally
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What type of fibers are free nerve endings made from?
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Free nerve endings are made of Penicillate fibers
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Where do you find free nerve endings on the body?
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Hair-bearing skin
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What 4 sensations do free nerve endings provide on hair-bearing skin?
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1) Touch
2) Pain 3) Temperture 4) Itch |
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What sensation do free nerve endings provide on non-hairy ridged areas of the skin?
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Fine touch discrimination
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Where are papillary nerve endings found?
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At the follicular orifice
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Where sensation are papillary nerve endings particularly sensitive to?
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Cold
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Where do you find Meissner's Corpuscles?
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In the dermal papilla of digital skin
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What 2 sensations do Meissner's Corpuscles detect?
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1) Touch
2) Light Pressure |
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Where do you find Pacinian Corpuscles?
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Deep in the dermis or SQ fat in weight-bearing areas of the body
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What type of sensation do Pacinian Corpuscles detect?
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Vibration
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What is the Pacinian Corpuscle?
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Mechanoreceptor
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What are Krase End-Bulbs?
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Mucocutaeous end-organs
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What 5 areas on the body can you find Krase End-Bulbs?
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1) Glans Penis
2) Prepuce 3) Clitoris 4) Labia Minora 5) Vermillion border of the lip |
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What are Langerhans cells and where do they originate from?
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Antigen Presenting cells
Originate from precursors in the bone marrow |
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What 3 places can you find Langerhans cells?
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1) Epithelial tissue
2) Lymph Nodes 3) Suprabasilar Layer of the Skin |
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What impairs Langerhans Cells?
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UVR
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To what cell do Langerhans cells present antigens to?
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T-cells with MCH II
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What are Glomus cells, and what do they do?
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Vascular smooth muscles that shunt from A➜V to bypass capillaries
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Where can you find Glomus cells on the body?
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Hands & Feet
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What are Glomus cells derived from?
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Suquet-Hoyer canals
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What are Merkel cells?
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Mechanoreceptor
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What layer of the skin can you find Merkel cells?
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Basal Layer
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What are Merkel cells?
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Mechanoreceptors that have connections with neurons
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What stain do you use for Merkel cells?
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CK 20
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What is the normal transit time of keratinocytes from basal layer to the stratum corneum?
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14 days
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What is the normal time for keratinocytes to be shed from the stratum corneum?
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14 days
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Which 2 keratins are upregulated in Psoriasis?
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1) K6
2) K16 |
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Which 2 keratins are downregulated in Psoriasis?
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1) K1
2) K10 |
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Which 2 keratins are made in the Stratum Spinosum?
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1) K1
2) K10 |
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Which 2 keratins are produced in the Granular Layer?
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1) K2 (K1➜K2)
2) K11 (K10➜K11) |
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Which 3 keratins are produced in the Basal Layer?
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1) K5
2) K14 3) K19 |
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Which diseases are associated with Gap Junction mutation in connexin-26?
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1) Vohwinkel's Syndrome
2) Keratitis-Ichthyosis-Deafness Syndrome (KID) 3) PPK with deafness |
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Which disease is associated with Gap Junction mutation in connexin 30.3 and 31?
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Erythrokeratoderma Variabilis
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What disease is associated with Gap Junction mutation in connexin-30?
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Clouston's Syndrome (Hidrotic Ectodermal Dysplasia)
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Lamellar Granules or Odland Bodies are found where?
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First apparent in the upper spinous layer, but primary site of action is the granular layer
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Diseases Associated with Lamellar Granules or Odland Bodies
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1) Flegel's
2) Harlequin Fetus 3) X-linked Icthyosis |
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In the granular layer, filaggrin is catabolized to what?
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Urocanic Acid
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Urocanic Acid serves what function?
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Provides UV Protection
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What are the proteins of the Cornified Envelope?
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Filaggrin, Loricrin and Involucrin
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What is the #1 Protein of the Cornified Envelope (CE)?
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Loricrin (75% of CE's Mass)
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What disease is associated with Transglutaminase 1?
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Lamellar Icthyosis
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What disease is associated with Transglutaminase 3?
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Dermatitis Herpetiformis
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What are the 4 stages of wound healing?
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1) Inflammatory Stage
2) Epithelialization 3) Granulation 4) Wound Contraction |
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Which cell is required for wound healing?
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Macrophages
-provide debridement and secretion |
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If the basal layer is lost, what 3 proteins act as a provisional matrix in wound healing?
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1) Collagen 5
2) Fibrin 3) Fibronectin |
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What is the sequence of granulation tissue formation?
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Fibronectin ➔ Collagen 3 ➔Collagen 1
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When does granulation tissue start to form after injury?
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4 days
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Which 2 cells are the first to respond to tissue injury?
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1) Neutrophils (greater in number)
2) Monocytes |
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What proteoglycan deposit helps to increase wound strength?
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Hyaluronan
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What is scar strength at 1 week?
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5%
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What is scar strength at 3 weeks?
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20%
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What is scar strength at 1 year?
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80%
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Where do you find Lanugo hair?
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Fine hair found on the fetus
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What defines Vellus Hair?
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Hair less than 1cm in length
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What defines Indeterminate Hair?
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Hair that is 1cm long
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What defines Terminal Hair?
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Hair longer than 1cm
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What are the layers of the hair follicle, from outside->inside?
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ORS->IRS->Henle's layer->Huxley's layer-> Cuticle -> Cortex -> Medulla
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What is the Critical line of Auber?
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-The widest diameter of the hair bulb
-Most mitotic activity is below this line |
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Hair styling breaks what bonds?
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Disulfide bonds
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What is the time cycle and % of Anagen hair on the scalp?
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2-6 years
85% of all hairs |
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What is the time cycle and % of Catagen hair on the scalp?
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2-3 weeks
1% of all hairs |
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What is the time cycle and % of Telogen hair on the scalp?
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2-3 months
14% of all hairs |
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Eumelanin is found in what color hair?
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Black hair
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Pheomelanin is found in what color hair?
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Red or Blond Hair
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Red hair corresponds to what mutation of what receptor?
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Loss of function mutation of Melanocortin-1 Receptor (MC1R)
Shifts from Eumelanin to Pheomelanin |
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What type of stimulation do Eccrine Glands need?
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Cholinergic Stimulation
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What 2 stains are positive in Eccrine Glands?
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S-100 and CEA
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What type of secretion do Sebaceous Glands exhibit?
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Holocrine secretion
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What type of secretion do Apocrine Glands exhibit?
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Decapitation Secretion
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Where are Apocrine Glands found?
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1) Axilla
2) Anogenital areas 3) External Auditory canal = Ceruminous 4) Eyelids = Moll's Glands 5) Breast = Mammary Glands |
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What causes the odor in Apocrine Glands?
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C6-C11 Acids
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What is the function of the BMZ?
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Supportive structure to anchor the epidermis to the dermis
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How does the BMZ anchor the epidermis to the dermis?
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Anchoring occurs through the cytoskeleton in keratinocytes, that bind to Laminin 5 in the Lamina Lucida
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What does Laminin 5 bind to?
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Laminin 5 in the Lamina Lucida binds to Type 7 Collagen in the Lamina Densa
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What is the function of Hemidesmosomes?
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Hemidesmosomes are the anchoring complex that attach basal cells of the epidermis to the basement membrane
They link the keratin cytoskeleton of basal cells to Laminin 5 which is in the Lamina Lucida |
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What are the 3 portions of Hemidesmosomes?
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1) Cytoplasmic Portion
-Attachment Plaque 2) Transmembrane Portion -BP antigen 2 (180kD) -Integrin 3) Extracellular Portion (in the Lamina Lucida) -Anchoring filaments -Subbasal dense plate |
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What makes up the cytoplasmic portion of the hemidesmosome?
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They cytoplasmic portion is the attachment plaque. The attachment plaque= BPAg1 and Plectin
-K5 and K14 are bound to the plaque by Desmocalmin and Desmoplakin -Intracellular portion of BPAg2 (180kD) and Collagen 17 are also present |
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What are the components of the transmembrane portion of the hemidesmosome?
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1) BPAg2
2) a6b4 integrin (interacts with Laminin 5 to form anchoring filaments) |
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What makes up the extracellular portion of the hemidesmosome?
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-Integrins and BPAg2 cross the membrane (transmembrane portion) and attach to the sub basal plate
-Anchoring filaments made from a6b4 integrin & Laminin 5, extend from the sub basal plate into the lamina densa, |
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What is the weakest layer of the BMZ?
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Lamina Lucida
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What is the Lamina Lucida?
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-Electron-Lucent zone
-Made of Laminin 1, Nidogen (Entactin) and Fibronectin -Anchoring filaments (Laminin 5 & a6b4 integrin) cross the lamina lucida -One side connects to the attachment plaque of the plasma membrane of the basal k-cyte -The other side connects to the sub basal dense plate |
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What are the components of the Lamina Densa?
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1) Type 4 Collagen
2) Entactin (Nidogen): binds laminin, collagen 4, perlecan, and fibulins 3) Fibulins |
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What are Fibulins?
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Calcium-Binding Extracellular matrix proteins
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What do Fibulins do?
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Function to support the structural network of different basement membranes by joining other supramolecular structures, elastic fibers, and aggregates
-found in basement membranes and vessel walls |
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What disease is associated with a mutation in Fibulin-1?
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Marfan's Syndrome
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What is the Sublamina Densa composed of?
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Type 7 collagen
-Contains network of anchoring fibrils |
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What do anchoring fibrils attach to?
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Anchoring fibrils originate in the Lamina Densa, dip down into the dermis, and attach to an anchoring plaque or loop back to reinsert into the Lamina Densa
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How long does it take for complete renewal of the epidermis?
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26-28 days total
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What interleukin do Langerhans cells produce?
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IL-1
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Describe the components of the Desmosome
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・Connects K-cytes together, structure consists of:
・A desmosomal plaque on the inside of the cell membrane ・Transmembrane glycoproteins ・Central plate that crosses the intercellular space between 2 keratinocytes |
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What are the 7 components of the Desmosomal plaque?
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1) 6 polypeptides
2) Plakoglobin 3) Desmoplakin 1 4) Desmoplakin 2 5) Keratocalmin 6) Desmoyokin 7) Band 6 Protein |
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What do adhesion molecules do?
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・Cell-to-cell adhesion, interaction between cells, cell signaling, inflammation, migration of cells, wound healing, embryogenesis
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Name the 4 families of adhesion molecules
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1) Cadherins
2) Integrins 3) Selectins 4) Immunoglobin supergenes |
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What are tight junctions and what do they do?
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Composed of proteins called Claudins
・Regulates epidermal barrier permeability ・Mutation in Claudin-1 linked to rare icthyosis |
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What are gap junctions and what do they do?
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・Allow for communication between cells
・Made of connexins |
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What are Lamellar Bodies (aka Odland bodies)?
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Secretory Organelles (Lysosomes) found inside keratinocytes in the stratum spinosum.
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What is the purpose of Lamellar bodies (Odland bodies)?
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Ceramide helps with barrier function and adhesion
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What are Keratohyaline granules?
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・Blue granules that contain Profilaggrin, and Loricrin
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Where is Filaggrin cleaved from Proilaggrin?
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At transformation from granular to horny layer
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What function do Keratohyaline granules serve?
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Involved in formation of cornified cell envelope
-rich in sulfur |
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What is the Cornified cell envelope (CCE)?
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An extremely durable protein-lipid polymer
-assembled on the interior of the keratinocyte -eventually resides on the exterior of the corneocyte |
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What does the CCE do?
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Provides a mechanical and chemical barrier
-Calcium-dependant transglutaminases create an insoluble shield |
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Where does the dermis originate from?
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Mesodermal origin
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What is the major protein of the Dermis and what makes it?
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Collagen is the major protein of the Dermis
Fibroblasts make collagen |
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Which type of collagen is common in adult skin?
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collagen type 1
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Which type of collagen is common in fetal skin?
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Collagen type 3
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What are the components of the Dermis?
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1) Ground substance
2) Subpapillary vascular plexus 3) Deeper vascular plexus (around hair follicles and eccrine sweat glands) 4) Fibroblasts, Macrophages, and Mast cells |
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Which type of nerve fibers are in the dermis?
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Unmyelinated nerve fibers (C-type)
-Detect temperature, pain and itch -located in the papillary dermis and basal layer -Encapsulated nerve endings detect touch and pressure |
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What are Cadherins?
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Calcium-dependant cell-cell adhesion molecules
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What are integrins and what do they do?
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Integrate intracellular cytoskeleton with extracellular matrix
-2 sub-units: α and β |
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What do Lamellar (Odland) bodies secrete and where?
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Store & secrete ceramide into the extracellular matrix (inter-cellular space)
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What are the 2 characteristics of Type 1 Keratins?
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1) Smaller
2) Acidic |
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What chromosome is associated with Type 1 Keratins?
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Chromosome 17
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Which keratins are type 1 keratins?
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K9-20
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What are the 2 characteristics of Type 2 Keratins?
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1) Larger
2) Basic |
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What chromosome is associated with Type 2 Keratins?
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Chromosome 12
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Which keratins are type 2 keratins?
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K1-8
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What is the structure of collagen?
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Glycine-X-Y structure
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Which 2 amino acids are important for Elastin?
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1) Isodesmosine
2) Desmosine |
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Which amino acid is important for Vimentin?
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1) Citrullin
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Which 2 amino acids are important for Collagen?
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1) Hydroxylysine
2) Hydroxyproline |
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Name the 4 most important intermediate filaments (aka tonofilaments)
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1) Keratins
2) Vimentin 3) Desmin 4) Neurofilaments |
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What cell is the first responder to release mediators like ADP in tissue injury?
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Platelets
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How soon does re-epithelialization begin after injury?
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Starts within hours
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Which 2 enzymes help during re-epithelialization?
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1) Integrin receptors guide the path
2) Collagenase assists |
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What cell type is most important for wound contraction?
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Myofibroblasts (contain actin)
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At how many weeks into gestation do the first hair follicles form?
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9 weeks gestation
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Where do the first hair follicles form?
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On the face
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Which part of the follicle maintains the integrity of the hair?
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Cuticle
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What part of the follicle contains the bulk of the keratins?
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Cortex
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During which hair cycle are pluripotent matrix keratinocytes most active?
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Anagen
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During which hair cycle does thinning and loss of pigment of the hair occur?
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Catagen
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At which hair cycle stage do the matrix cells terminally differentiate?
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Catagen
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During which hair cycle is club-shaped hair shed?
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Telogen
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At which hair cycle stage is the IRS absent?
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Telogen
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Melanin is formed only during this hair cycle stage
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Anagen
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When do sebaceous glands enlarge?
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After puberty
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Which 2 areas do you not find sebaceous glands?
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1) Palms
2) Soles |
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Name the 3 areas with unique sebaceous glands
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1) Montgomery's Areolar Tubercles
2) Fordyce Spots 3) Meibomian Eyelid glands |
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Why are Montgomery's areolar tubercles unique sebaceous glands?
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・No hair associated
・Free standing glands |
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Where do you find sebaceous glands?
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Everywhere, usually associated with hair follicles.
EXCEPT: PALMS & SOLES |
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Where do you find Fordyce spots?
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Free sebaceous glands on the vermillion
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What are Meibomian glands?
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Modified sebaceous glands on the eyelids
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What is the #1 component of sebum?
|
Glycerides
-followed by wax esters and squalene |
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What are epidermal lipids composed of?
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Mostly glycerides, followed by cholesterol.
-NO wax esters or squalene |
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Name the 5 areas where you can find Apocrine Glands.
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1) Axilla
2) Anogenital 3) External Auditory Canal (ceruminous) 4) Eyelids (Moll's) 5) Breast (Mammary) |
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What type of secretion do you see with ceruminous glands in the external auditory canal?
|
Decapitation (Apocrine)
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What are Moll's glands in the eyelid?
|
Apocrine glands
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What type of secretion do you see in the Mammary glands?
|
Decapitation (Apocrine)
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What are the 3 main components of the BMZ?
|
1) Lamina Lucida
2) Lamina Densa 3) Sub-lamina Densa |
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Which of the anchoring filaments is dumbbell shaped?
|
Nidogen (entactin)
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What do anchoring filaments bind?
|
Laminin 1
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Where do we get vitamin D2 & D3 from?
|
Diet
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On the skin, what acts on 7-dehydrocholesterol to form Vitamin D3?
|
UVB
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Skin-derived vitamin D3 binds to what to be transported to the liver?
|
Vitamin D transport-protein
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In the liver vitamin D3 is hydroxylated at what position to produce calcidiol?
|
25' position
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Where is calcidiol transported to?
|
Kidney
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In the kidney, calcidiol is acted on by what to produce calcitriol (1,25-dihydroxycholecalciferol)?
|
1-hydroxylase
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Name the 4 main Cadherins.
|
1) Desmocollin
2) Desmoglein 3) E Cadherin 4) P Cadherin |
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"DEP is Cad"
|
D esmoglein and Desmocollin
E cadherin P cadherin |
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What 4 cells make up the epidermis?
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1) Keratinocytes 80%
2) Melanocytes (base layer) 3) Langerhans cells (suprabasal 2-8%) 4) Merkel cells (basal layer) |
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This cell can release, respond to and produce TNF-alpha.
|
Langerhans cells
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