DD-Dermal Structures & Diseases Flashcards
The dermis is a tough but elastic support structure that lies beneath the _______ and
above the subcutaneous tissuE
epidermis
The dermis contains blood vessels, nerves, and _________ (hairs, sweat glands/ducts, etc.)
cutaneous appendages
The dermis ranges in thickness from about ___mm
1-4 mm
The epidermis contains _________ blood vessels
NO
depends on dermis
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.
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
Three “Building Blocks”
of the Dermis
- Collagen – forms the tensile strength
- Elastic fibers – allow for resilience
- Ground substance – facilitates diffusion
Dermis collagen
Collagen 1 = >85 wt.% of adult dermis
Vitamin____required co-factor in collagenn synthesis
Vitamin C
Essentials of Collagen
Production
Procollagen (from fibroblasts)
- -> cleaved into TROPOcollagen
- -> linked by Vit. C
–keratotic plugging of hairs
– perifollicular hemorrhage
– “corkscrew” hairs
– hemorrhagic gingivitis
These finding indicate?
Scurvy
Lack of collagen support for ______ leads to rupture & hemorrhage (same for gums)!
blood vessels
- A family of disorders based upon poor collagen synthesis
* Mutations at various stages of collagen
Ehlers-Danlos Syndrome
An Acquired Disorder of Elastic Fibers
Solar Elastosis
- Caused by a mutation in MDR gene
* Net result - calcified, brittle elastic fibers
Pseudoxanthoma Elasticum
– hyperextensible skin
– hyperextensible joints
– fragile blood vessels
– poor wound healing
are symptoms of?
Ehlers-Danlos Syndrome
– “plucked chicken” skin – systemic hypertenision – angioid streaks in the retina – arterial rupture (particularly in the eye)
Pseudoxanthoma Elasticum
- Minor constituent of dermis, provides resiliency
- Thin fibers (1-3 um)
- Intertwined among collagen bundles
- Special stains are required to visualize (VVG)
Elastic Fibers
• 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
Cosmetic hyaluronic acid filler may represent an acquired
disorder of _________
ground substance
• Skin vessels considered as two plexi:
– superficial plexus
– deep plexus
Psoriasis and verruca share what pathology?
Disorders of Capillary Loops
“Palpable purpura” - combination of inflammation and _________
hemorrhage
Two Important Types of Nerve
Fibers to Be Aware Of
Type A and Type C
unmyelinated, slow-conducting dermis nerve
Type C
Temp/Itch control
heavily myelinated, conduct rapidly
Type A
“Palpable purpura” - combination of ________ and hemorrhage
inflammation
Pruritus
Itch
4 things that can trigger itch:
– dry skin (xerosis)
– infection (HIV)
– infestation (scabies or lice)
– metabolic disorders (renal failure)
Meissner’s Corpuscles
control fine touch in skin
Pacinian Corpuscles
deep pressure and vibration (common in genitals)
2 Types of hair:
Terminal Hairs- scalp
Vellushair- thin/ no color (ears)
Androgenic (Androgenetic) Hair Loss
AKA “pattern baldness” • Characteristic loss • 50% of population • Conversion of testosterone to DHT • Results in miniaturization of follicle
Lubricate thick terminal hairs
Sebaceous Glands
abnormal follicular maturation
plugged follicular environment allows overgrowth of P. acnes
later events yield dermal inflammation
Acne
- Odorless, watery sweat
- VITAL to thermoregulation
- Merocrine secretion
- Sympathetic innervation
- utilizes acetylcholine
- NOT derived from the PEG
Eccrine Glands
“sweat” glands
miliaria is not
it is miliaria
it IS NOT malaria
What is miliaria
prickly heat
Blocked sweat ducts
Manifestations depend upon site of blockage
Outgrowths of the upper bulge of PEG
• Located in axillary and anogenital area
• Small and nonfunctional until puberty
sweat is “stickier” (sialomucin)
Apocrine Glands
Hybrid sweat glands
• Located mainly in axilla
• Likely play a role in axillary hyperhidrosis
• high volume, thick product
Apoeccrine Glands
