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Disease & Defense - Unit 3 > Dermis Structure > Flashcards

Flashcards in Dermis Structure Deck (16):
1

Basic structure of the skin

-epidermis (superficial) adhered to dermis just below by the dermoepidermal junction

2

Dermal matrix composition

-collagen fibers + elastin fibers + ground substance
-synthesized by fibroblasts w/in dermis

3

Characteristics and purpose of dermoepidermal jucntion

-epidermal rete=downward projections of epidermis
-dermal papillae=upward projections of dermis
-interlocking pattern increases adherence strength and surface area (btwn epidermis and dermis) --> passage of nutrients
-pattern on hands and feet --> epidermal ridges ("fingerprints")

4

General characteristics and typesof collagen

-"building block" of dermis
-provides tensile strength of skin
-three proteins arranged in alpha-helical structure
-repeated strings of Gly-X-Y (usually Gly-Pro-hydroxyproline)
-Main types: Collagen I, III, IV, VII

5

Type I Collagen characteristics

- >85% of adult dermis
-major component of bone

6

Type III Collagen characteristics

-fetal dermis component
-reason why fetal skin forms less scars

7

Type IV Collagen characteristics

-high concentrations found in basement membrane zone (i.e. @ dermoepidermal jxn)
-prominent around vessels

8

Type VII Collagen characteristics

-found anchoring fibrils
-used to to attach epidermis to dermis

9

Sites of collagen synthesis and assembly

-synthesis=intracellular (fibroblasts)
-assemnly=extracellularly (w/cofactors --> vit C)

10

Ehlers-Danlos syndrome (EDS) characteristics

-disordered collagen production due to genetic defects
-skin hyperextensibility, joint hyperextensibility
-tissue fragility
-poor wound healing

11

Elastic fiber characteristics

-provide skin resiliency=ability to be distorted and return to orignal shape
-normally argyrophillic="silver-loving" --> visible w/silver-based stains
-sun-damaged elastic fiber (e.g. in solar elastosis) =basophillic

12

Pseudoxanthoma elasticum (PXE) characteristics

-mutation in gene encoding multidrug resistance complex
-elastic fibers-->enlarged, tangled, and calcified
-histologically blue-purple
-"plucked-chicken" skin

13

Ground substance components

-gelatinous material between and amongst collagen bundles, elastic fibers, other structures of dermis
-glycosaminoglycans: hyaluronic acid and dermatan sulphate (can absorb water)
-fibronectins="glue"
-helps facilitate nourishment of epidermis
-constantly being destroyed and renewed

14

Functions of cutaneous vascular system

-wound healing
-control of homeostasis: via Sucquet-Hoyer canal (smooth muscle valve) blood directed towards or away from skin
-modulation of inflammation/leukocyte trafficking: express intracellular adhesion molecules (ICAMs) that allow adherence and rolling of WBCs

15

Leukocytoclastic vasculitis characteristics

-immune complex formation within post-capillary venules in dermis
-often post-Strep infection
-palpable purpura

16

Important nervous tissue structures in dermis

-meissner's corpuscles
-free nerve endings
-pacinian corpuscle