Structure and Function Flashcards
0
Q
Meissner corpuscles
A
Located in dermal papillae
Touch
Palms and soles
1
Q
Langerhans cell stain
A
CD1a
2
Q
Apocrine gland secretion
A
Decapitation
3
Q
Vater-Pacinian corpuscles
A
Located in deep dermis of palms, dorsum hands, soles, nipples, anogenital region
Pressure
4
Q
Apocopation
A
Process by which melanocytes transfer melanosomes to keratinocytes via phagocytosis of melanocytic dendritic processes by keratinocytes
5
Q
Type I and Type II Keratins (Acid/base, chromosomes)
A
Type I: Acidic, Keratins 9-20 (ch17)
Type II: Basic, Keratins 1-8 (ch12)
6
Q
Keratin of upper stratum spinosum
A
Keratin 1 and 10 (Congenital bullous ichthyosiform erythroderma)
7
Q
Keratin of basal layer
A
Keratin 5 and keratin 14 (Epidermolysis bullosa simplex)
8
Q
Normal turnover of epidermis
A
26 to 28 days. (13 to 14 days for basal layer corneum and 13 to 14 days for shedding)
9
Q
Merkel cell
A
Type I mechanoeceptor
Derived from ectoderm and neural crest cells
10
Q
Two types of melanin pigment
A
Eumelanin (Brown and black)
Pheomelanin ( Red or yellow)
11
Q
Antigen processing system and interleukin of Langerhans cell
A
MHC class II presentation to T cells IL-12
12
Q
Desmosomal cadherins (With diseases)
A
Desmogleins (membrane bound):
desmoglein 3 = pemphigus vulgaris
desmoglein 1 = pemphigus folaceous
Desmocollins (membrane bound)
Plakoglobin (cytoplasmic)
Desmoplakin (cytoplasmic,in both desmosomes and adherens junctions)
13
Q
Connexin-26 mutation
A
GJB 2
Vohwinkels syndrome & keratitis-ichthyosis-deafness syndrome
14
Q
Producer of the hydrophobic barrier between granular in cornfield layers
A
Lamellar granules (Odland bodies)
Contain precursors to ceramides
Extrude lipids and enzymes into intercellular space
15
Q
Types of collagen found in the dermis of adults and fetuses
A
Adults: Type I & III
Fetuses: Type III
16
Q
Fibulin
A
Calcium binding extracellular matrix proteins in the lamina densa
Support structural network of BM
Fibulin-1 mutation = Marfan syndrome
17
Q
Anchoring Fibrils Location and Collagen
A
Lamina densa –> dermis –> anchoring plaque/lamina densa
Collagen VII
18
Q
Microfibrils of lamina densa
A
Elaunins = Horizontal Oxytalins = Perpendicular
19
Q
Integrins
A
Integrate intracellular cytoskeleton with extracellular matrix
20
Q
Integrin Beta 4 (alpha6beta4)
A
In hemidesmosome of basement membrane
Binds to laminin 5 in anchoring filaments
Role in junctional epidermolysis bullosa
21
Q
Selectins
A
Mediate recruitment of inflammatory cells
L (Leukocyte)
P (Platelet) - stored in Weibel-Palade bodies of endothelium
E (Endothelial) - produced in response to IL-1 and TNF
22
Q
What does E-cadherin do
A
Langerhan cells to epidermis
23
Q
Location of Langerhan cell in epidermis
A
Stratum spinosum
24
Eccrine gland secretion
Merocrine
25
Sebaceous gland secretion
Holocrine
26
Level of desmosomes in epidermis
Stratum spinosum
27
Stem cell rich sites
Rete ridges and hair bulge
28
Keratohyaline granule contents (3)
Profilaggrin, keratin, Loricrin
Results in soft flexible keratin
29
Two products of filaggrin and function
Urocanic acid & pyrrolidone carboxylic acid
Hydrates stratum corneum
Blocks UV radiation
30
Keratinocyte cytokines and interleukins
IL-1, IL-8, TGF-B
31
Six desmosomal plaque proteins
Plakoglobin, desmoplakin I &II, desmocalmin, desmoyokin, band 6 protein
32
Connexin-30 mutation
GJB 6
| Cloustons syndrome
33
Connexin- 30.3 and 31
GJB 4 and 3
Erythrokeratoderma variablis
34
Melanin production regulator
MCR1 receptor
Loss of function mutation in red heads
35
Specific keratin of merkel cell
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Cytokeratin 20 (K20)
Paranuclear dot pattern
```
36
Type of collagen in the lamina densa
Collagen IV
37
5 Members of Plakin Family
BPAg1, desmoplakin, periplakin, envoplakin, plectin
38
Two amino acids in elastic fibers
Desmosine and Isodesmosine
39
Which element is necessary for melanin production
Copper (needed for tyrosinase)
40
Elastin stains
Verhoeff-van Gieson, Orcean, Resorcin-Fuchsin
41
Ground substance components
Glycosaminoglycans - hyaluronic acid
| Proteoglycans - versican,perlecan
42
Macrophage receptors/stains
S100, factor XIIIa, CD68, CD163, CD25
43
Dendritic cell receptors
Factor XIIIa (dermatofibroma, angiofibroma, fibrous papules)
CD34 (around hair follicle, DFSP) (absent in morphea)
44
Mast cell stains
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Toludine blue
Methylene blue
Giemsa
Leder (good when mast cells have degrantulated)
Chymase, tryptase
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45
Glomus cells
Derived from susquet-hoyer canals
| Found between arterioles and venules, shunt blood and temperature
46
Eccrine duct sections and innervation
Acrosyringium, straight dermal portion, coiled secretory portion in panniculus
Cholinergic innervation (C fibers)
47
Eccrine gland stains
S100, CEA
48
3 sections of hair follicle
```
Infundibular segment (epidermis to sebaceous duct)
Isthmus (sebaceous duct to arrector pili insertion)
Inferior segment (bulb, dermal papilla)
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49
Critical line of Auber
Widest diameter of bulb
Bulk of mitotic activity that gives rise to hair and IRS
ORS occurs below this level
50
Layers of hair bulb from inner to outer
Hair shaft (medulla, cortex, cuticle), inner root sheath (cuticle, Huxley, Henley), outer root sheath
51
First layer of inner root sheath to be cornified
Henle
52
Growth rate of hair
0.37 mm/day
53
Oral mucosa sebaceous glands
Fordyce spots
54
Eyelid sebaceous glands opening into follicle
Mebomian glands
55
Nipple sebaceous glands
Montgomry tubicles
56
Sebaceous glands of penis
Tyson glands
57
Sebaceous glands of eyelids that don't open into follicle
Zeiss glands
58
Content of sebum
Glycerides, Wax esters and squalene
59
Growth rate of fingernails
0.1 mm/day
| 4-6 months to regrow nail
60
Growth rate of toenails
0.03 mm/day
| 12-18 months to replace toenail
61
The proximal nail matrix is formed by which plate
Dorsal plate
62
The distal nail matrix is formed by which plate
Ventral plate
63
Once keratinocytes flatten and reach the granular layer, they lose nuclei and extrude all cellular contents except what two components?
Keratin and filaggrin
64
Keratins make up type __ and type __ intermediate filaments?
Type 1 and type 2 intermediate filaments
65
Which layer of the skin contains keratohyaline granules? What do the keratohyaline granules contain?
KH granules contain profilaggrin, keratin, loricrin. Results in formation of soft, flexible keratin.
66
What is filaggrin degraded to? What two functions do these products serve?
Urocanic acid & pyrrolidone carboxylic acid. Hydrates S.C. and blocks UV radiation.
67
What are Odland bodies (lamellar granules)?
Small, granular, membrane-bound vacuoles found in the cytoplasm of skin keratinocytes. They are derived from the Golgi apparatus and are associated with the storage and release of lipid precursors.
68
What are the six desmosomal plaque proteins?
Desmoplakins 1+2 (mediate attachement of keratins to plaque)
Desmocalmin (important for calcium regulation)
Band 6 protein
Plakoglobin (mediates attachment of keratins to plaque)
Desmoyokin (associated with cell membrane)
69
What are gap junctions composed of and what do they do?
GJ’s made up of connexons: A connexon is formed from six connexin molecules. Allow electrical and metabolic coupling among cells.
70
Name the corresponding connexins to the following gap junctions: GJB 2, GJB 3 and 4, GJB 6
Connexin 26 (GJB 2);Connexin 31 + 30.3 (GJB 3 and 4); Connexin 30 (GJB 6)
71
The adhesion molecules cadherins are ______ -dependent.
Ca2+
72
Name some desmosomal cadherins
Desmoglein, desmocollins (membrane-bound)
| Plakoglobin, desmoplakins (cytoplasmic)
73
Melanocytes are derived from _____
neural crest cells
74
Each melanocyte interacts with approximately how many keratinocytes?
36 keratinocytes. = the epidermal melanin unit
75
Why do melanocytes have a surrounding clear halo in the basal layer?
Melanocytes lack tonofiliments, therefore cannot form desmosomal attachments with keratinocytes.
76
How do the melanosomes in darker skin compare to those in lighter skin?
Melanosomes in dark skin are increased in size and number and are more singly dispersed. The have slow degradation.
77
What receptor/gene is the most important regulator of melanin production?
MCR1 receptor (melanocortin 1) is most important regulation of melanin production. Redheads: loss-of-function mutation MCR1.
78
Where are Langerhans cells derived from? What is their main function? Main marker?
Mesoderm/bone marrow derived. Function in antigen presentation. CD1a. Secrete IL-12.
79
UV exposure increases or decreases Langerhans cell population?
Decreases
80
What type of cell is the Merkel cell? What is the stain to remember with this one?
Neuroendocrine cell but also slow adapting type I mechanoreceptors. CK-20.
81
What virus is implicated in Merkel cell carcinoma?
Polyomavirus
82
What collagen makes up the lamina densa?
Collagen IV
83
The keratin intermediate filaments in the basal layer cell are made up of what keratins?
K5, 14
84
Anchoring fibrils are made up of what collagen?
Type VII collagen
85
What components traverse the lamina lucida?
Laminin 5 (epiligrin), anchoring filaments, BPAg 2 (= BP180, = Collagen 17)
86
Name the components of the lamina densa? There are 7.
Type IV collagen. Also have Laminin 5 (laminin 332), Laminin 6, laminin 10, nidogen (entactin), fibulin, and perlecan
87
The epidermal appendages develop between weeks _____ of gestation? In what order?
Weeks 18-24. Hair, sebaceous, eccrine, then apocrine
88
How are eccrine glands innervated?
Sympathetic cholinergic innervations. Through postganglionic C fiber production of acetylcholine.
89
Apocrine glands: what type of secretion? Contains? Innervation?
Decapitation secretion. Consists of protein, carbs, lipids, ammonia, iron, sialomucin. Adrenergic
90
Hair follicles develop during what weeks of gestation? Where on body first?
9-12 weeks. Head. Then Cephalad -> Caudal. Ectodysplasin A & noggin are essential for development
91
What is the name for the area with widest diameter of the bulb?
Line of Auber. Bulk of mitotic activity that gives rise to the hair and the IRS, ORS occurs below this level
92
Name the three main phases of hair growth and how long they last?
Anagen (3-5 yrs, active phase); Catagen (3wks, involution phase); Telogen (3-5mo, resting phase)
93
How does hair growth on the head differ from that on the body?
Compared to scalp (2-6 years), most areas of the body have SHORTER Anagen (growing) phase and LONGER Telogen (resting) phase
94
Name the different eyelid glands and what type they are (apocrine or sebaceous)?
Moll (apocrine), Meibomian (sebaceous, open into follicle), Zeiss (sebaceous, don’t open into follicle)
95
The dermis is made up of which collagens? Which are the “adult” and “fetal” collagens?
Collagens I, III, V. Type I (85%) – adult; Type III (10%) – fetal; Type V (5%)
96
Collagen hydroxylation is dependent on what cofactor?
Collagen hydroxylation: Prolyl and lysyl hydroxylase (require vitamin C)
97
Cross-linking of collagen molecules requires what cofactor?
Cross-linking of collagen molecules: Catalyzed by lysyl oxidase (requires copper)
98
What stimulates versus inhibits collagen production?
Stimulating collagen production: Ascorbic acid, TGF-B, Retinoic acid; Inhibiting collagen production: IL-1, Glucocorticoids, Interferon-_, TNF-_, D-Penicillamine, Minoxidil
99
What unique amino acids make up elastin?
Elastin contains the unique AA’s Desmosine, Isodesmosine
100
Describe the difference between oxytalin and elaunin microfibrils?
Oxytalin fibers: run perpendicular; insert into BM from papillary dermis. Elaunin fibers: run parallel in reticular dermis; low elastin content
101
Glycosaminoglycans and proteoglycans make up what?
Ground substance. A proteoglycan is a macromolecule with core protein and attached GAGs
102
Name two proteoglycans?
Versican and perlecan
103
Factor XIIIa and CD34 stain what type of cell? Which stains DFs? Which stains DFSP?
Dendritic cells. 13a in DF; CD34 in DFSP
104
Cross-linkage of involucrin into the S.C. envelope results from the activity of which enzyme?
Epidermal transglutaminase
105
Which cell am I? Neurosecretory granules are seen in the cytoplasm. The tumor cells stain with Neuron-specific enolase
Merkel cell/ Merkel cell carcinoma
106
Merkel cell stains
Neuron specific enolase (NSE), chromogranin, synaptophysin, VIP, CK20
107
Primary collagen of skin
Collagen I
108
Collagen of cartilage
Collagen II
109
Collagen of Fetal skin, papillary dermis, blood vessels, GI tract
Collagen III
