02 - Cells of the Epidermis Flashcards Preview

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1

(Keratinocytes)

1. most abundant

2. origin?

3. location?

(Function)

1. production of what? 

and what?

 

2. ectoderm

3. throughout epidermis

1. proteins involved in cornification or keratinization

intercellular lamellar lipid for cornified layer (stratum corneum)

2

(Keratinocytes)

(function cont)

1. play important role in epidermal immunity... produce what and what? 

can they be phagocytic?

can express what under influence of gamma interferon?

2. produce what whicih make holes on wall of bacteria, viruses, and protozoa?

1. cytokines and inflammatory mediators

yes

MHC-II (T-cell presentation)

2. cationic antimicrobial polypeptides (defensins and cathelicidins)

3

(CElls of the epidermis)

(melanocytes - one of the dendritic cells)

1. origin?

2. location?

(function)

1. production of what?

2. melanocytes appear how in H&E stain?

3. each communicates with a group of how many keratinocytes?

1. neural crest

2. basal layer of epidermis, hair follicle, ducts of sebaceous and apocrine glands

1. melanin

2. clear cells (have long dendritic processes)

3. 10-20

4

(Cells of the epiderms)

(langerhans cells - another epidermal dendritic cell)

1. origin?

2. location?

 

1. bone marrow

2. suprabasal layers of the epidermis

5

(Cells of the epiderms)

(langerhans cells - another epidermal dendritic cell)

(Function)

1. immune surveillance... antigen processing and presententaion (present what?) Important in the development of what?

2. can you see with H&E?

3. have tennis racket granules on EM in species other than what? known as what?

1. MHC II; contact dermatitis and graft rejection

2. no - require special stains

3. dogs; birbeck granules

6

(Cells of the epidermis)

(other cells)

1. cells positive for THy 1 antigen... may be what?

(Merkel cells)

2. epidermal clear cells confined to the stratum basale of what?

3. origin (2)?

4. function?

(more)

5. neutrophils, eosinophils, lymphocytes, erythrocytes can be present in the epidermis transiently in diseased states though a process known as exocytosis

6. ydelta-T cells also present in most mammals and participate in skin immunity

1. natural killer (NK) cells

2. the tylotrich pads

3. neural crest or ectoderm

4. slow adapting mechanoreceptors

7

(Life cycle of Epidermis)

1. what are three stages?

2. is normal desqumation visible?

3. what does shedding of visible scale indicate? why is this?

1. mitosis, differentiation, and exfoliation

2. rarely

3. disorder of keratinzation; more numbers of basal keratinocytes are undergoing mitosis - therefore whole process speeeds up (basal cell becomes keratinized faster)

8

(Specis and Regional Variation in Epidermal Thickness)

(hairy skin - dogs, cats, horses, cows, sheep, goats)

1. how thick are epidermis and stratum corneum?

2. epidermis is slightly undulating... are rete pegs formed?

3. varies in different areas of body

(Glabrous or un-haired - pigs, man)

1. how thick are epidermis/stratum cornuem)?

2. have rete pegs in dermis?

(thickness)

1. thickest where?

2. thinnest where?

1. thin

2. no

1. thicker

2. yes

1. over dorsum and neck

2. ventrum, axillae, inguinal

9

(Pigmentation)

1. the coat and skin color are the summation of what 4 things?

1. melanin (most important), blood flow, thickness, light transmission

10

(pigmentation)

(melanin)

1. what two compounds needed for melanin production?

2. what are two pigments?

3. settles on what side of keratinocyte?

4. usually present inside keratinovytes in what layers of epidermis

5. darkly pigmented animals have melanin throughout what?

 

1. tyrosinase and copper

2. eumelanin (brown-black), pheomelanin (red-brown)

3. sunny side

4. lower layers

5. epidermal layers

11

(pigmentation)

(melanin)

(cont)

1. transfer of melanosomes (contain melanin) may take place in what two ways?

2. what is transfer of melanosomes by melanocytes into keratinocytes by injection called?

1. fusion of melanocyte and keratinocyte; phagocytosis of tips of melanocyte dendrites by keratinocyte

2. cytocrinia

12

(Function of pigmentation)

1. protective against what?

2. provide camouflage

3. decorative

1. UV light

13

(Pigmentation is under genetic and hormonal control)

1. which hormones promote pigmentation?

2-4. what three other things promote?

1. MSH, ACTH, Androgens, estrogens, progesterones

2. UV light

3. inflammation

4. friction

14

(The following factors inhibit pigmentation)

(hormonal)

1. what from the pineal gland? antagonist to what?

2. what else?

(Chemical)

3. deficienvy of what?

4. excessive what?

5. various drugs

1. melatonin; MSH

2. corticosteroids (endo or exogenous)

3. copper

4. molybdenum

15

(The following factors inhibit pigmentation)

(genetic)

1. albinos: melanocytes present or no? what can't they produce?

2. absence in melanocytes called what?

1. no; melanin

2. piebaldism (due to abnormalties in melanocyte migration and development)

16

(The following factors inhibit pigmentation)

(miscellaneous)

1. physical destruction of melanocytes trhough injury... what melanocytes are more susceptible - those in hair follicles or in basal layer?

2-3. name two more processes...

1. hair follicles

2. immune mediated destruction of melonacytes (vitilgo)

3. inflammation

17

(Dermoepidermal Junction)

1. basement membrane zone joins what with what?

2. zone plays important role in establishing tissue architecture and is selectively permeable to what?

3. epidermis and dermis affect each other... communicate through what?

4. BMZ area is selectively attacked in what 3 diseases?

1. epidermis with its underlying connective tissue stroma (the dermis)

2. macromolecules

3. BMZ

4. bullous pemphigoid, epidermolysis bullosa, lupus erythmatosus (and some drug reactions)

18

(Dermis)

1. dermis supports and nourishes the epidermis... interacts with it closely during what things?

2. what is the thicketst part of the skin?

3. a complex matrix of fibers, ground substance, and cells, through which blood vessels and nerves course

1. embryogensis, morphogenesis, and wound repair and remodeling

2. dermis

19

(cells of the dermis)

(fibroblasts)

1. produce what? 

2. also produce what glycoprotein important in wound-healing, adhesion, and cell communication?

 

1. collagen, elastic and reticular fibers, and ground substance; 

2. fibronectin

20

(cells of the dermis)

(mast cells)

1. located where?

2. important in what type of hypersensitivyt rxns?

3. antigens crosslink which antibody? results in what?

 

1. around vessels and nerves

2. type I

3. IgE; mast cell degranulation (inflammation)

21

(cells of the dermis)

(histiocytic cells)

1. tissue monocytes which can be activated to what?

2. dermal dendritic cells... function as what?

3. present where?

4. those that have phagocyttized melanin called what?

5. in some species... melanocytes also present where?

1. macrophages

2. antigen processing and presenting cells (like Langerhaans)

3. around vessels

4. melanophages

5. dermis