DD-Dermal Structures & Diseases Flashcards Preview

BL/DD USMLE and Basics > DD-Dermal Structures & Diseases > Flashcards

Flashcards in DD-Dermal Structures & Diseases Deck (40):
1

The dermis is a tough but elastic support structure that lies beneath the _______ and
above the subcutaneous tissuE

epidermis

2

The dermis contains blood vessels, nerves, and _________ (hairs, sweat glands/ducts, etc.)

cutaneous appendages

3

The dermis ranges in thickness from about ___mm

1-4 mm

4

The epidermis contains _________ blood vessels

NO

depends on dermis

5

The dermis may be further subdivided into two zones:

a) the papillary dermis (located immediately beneath the epidermis)

b) the reticular dermis located
deeper in the tissue.

6

term often used to describe the admixture of collagen fibers, elastic fibers and ground substance all of which are synthesized by dermal fibroblasts.

Dermal matrix

7

Three “Building Blocks”
of the Dermis

1. Collagen – forms the tensile strength
2. Elastic fibers – allow for resilience
3. Ground substance – facilitates diffusion

8

Dermis collagen

Collagen 1 = >85 wt.% of adult dermis

9

Vitamin____required co-factor in collagenn synthesis

Vitamin C

10

Essentials of Collagen
Production

Procollagen (from fibroblasts)
--> cleaved into TROPOcollagen
--> linked by Vit. C

11

--keratotic plugging of hairs
– perifollicular hemorrhage
– “corkscrew” hairs
– hemorrhagic gingivitis

These finding indicate?

Scurvy

12

Lack of collagen support for ______ leads to rupture & hemorrhage (same for gums)!

blood vessels

13

• A family of disorders based upon poor collagen synthesis

• Mutations at various stages of collagen

Ehlers-Danlos Syndrome

14

An Acquired Disorder of Elastic Fibers

Solar Elastosis

15

• Caused by a mutation in MDR gene
• Net result - calcified, brittle elastic fibers

Pseudoxanthoma Elasticum

16

– hyperextensible skin
– hyperextensible joints
– fragile blood vessels
– poor wound healing

are symptoms of?

Ehlers-Danlos Syndrome

17

– “plucked chicken” skin
– systemic hypertenision
– angioid streaks in the retina
– arterial rupture
(particularly in the eye)

Pseudoxanthoma Elasticum

18

• Minor constituent of dermis, provides resiliency
• Thin fibers (1-3 um)
• Intertwined among collagen bundles
• Special stains are required to visualize (VVG)

Elastic Fibers

19

• Protein-sugar moieties
– absorb 10,000x their weight in h2o:
– hyaluronic acid
– dermatan sulphate
• “Glued” together with fibronectins

• Gelatinous mass that functions as a sponge- makes diffusion possible

Ground Substance

20

Cosmetic hyaluronic acid filler may represent an acquired
disorder of _________

ground substance

21

• Skin vessels considered as two plexi:

– superficial plexus
– deep plexus

22

Psoriasis and verruca share what pathology?

Disorders of Capillary Loops

23

“Palpable purpura” - combination of inflammation and _________

hemorrhage

24

Two Important Types of Nerve
Fibers to Be Aware Of

Type A and Type C

25

unmyelinated, slow-conducting dermis nerve

Type C

Temp/Itch control

26

heavily myelinated, conduct rapidly

Type A

27

“Palpable purpura” - combination of ________ and hemorrhage

inflammation

28

Pruritus

Itch

29

4 things that can trigger itch:

– dry skin (xerosis)
– infection (HIV)
– infestation (scabies or lice)
– metabolic disorders (renal failure)

30

Meissner’s Corpuscles

control fine touch in skin

31

Pacinian Corpuscles

deep pressure and vibration (common in genitals)

32

2 Types of hair:

Terminal Hairs- scalp
Vellushair- thin/ no color (ears)

33

Androgenic (Androgenetic) Hair Loss

AKA “pattern baldness”
• Characteristic loss
• 50% of population
• Conversion of testosterone to DHT
• Results in miniaturization of follicle

34

Lubricate thick terminal hairs

Sebaceous Glands

35

abnormal follicular maturation

plugged follicular environment allows overgrowth of P. acnes

later events yield dermal inflammation

Acne

36

• Odorless, watery sweat
• VITAL to thermoregulation
• Merocrine secretion
• Sympathetic innervation
• utilizes acetylcholine
• NOT derived from the PEG

Eccrine Glands
"sweat" glands

37

miliaria is not

it is miliaria

it IS NOT malaria

38

What is miliaria

prickly heat
Blocked sweat ducts
Manifestations depend upon site of blockage

39

Outgrowths of the upper bulge of PEG
• Located in axillary and anogenital area
• Small and nonfunctional until puberty
sweat is “stickier” (sialomucin)

Apocrine Glands

40

Hybrid sweat glands
• Located mainly in axilla
• Likely play a role in axillary hyperhidrosis
• high volume, thick product

Apoeccrine Glands