Pathophys/Path Flashcards
1
Q
Layers of skin?
A
- Epidermis
- Dermis
- Subcutis
2
Q
Cells in Epidermis?
A
Keratinocytes
Melanocytes
Langerhans cells
Markel cells
3
Q
Cells in Dermis?
A
Fibroblasts Collagen Elastic Blood Vessels Nerve Endings
4
Q
Cells in Subcutis?
A
Fat
Blood Vessels
Fibrous Septae
5
Q
Epidermis
A
- Primarily barrier function, protection, wound healing
- Barrier-structure and organization
- Wound healing-must be able to “fix” itself
- Self-renewing, sheds every 28 days
- Cells grow from stem cells in basal layer and terminally differentiate as the move up
- Apoptosis normally low in epidermis (can increase)
- 4 Layers
6
Q
4 layers of Epidermis?`
A
1) basal
2) spinous
3) granular
4) stratum
7
Q
Basal Layer
A
- In epidermis
- Source of stem cells
- Division starts here
- Basal cells adhear to dermis (BM zone) through HEMIDESMOSOMES
8
Q
Spinous Layer
A
- In epidermis
- Cells stop dividing/start terminal differentiation
- Develop lipid (lamellar granules) important to barrier function
- “spiny” due to visible DESMOSOMES with which one KC adheres to another
9
Q
Granular Cell Layer
A
- In epidermis
- Intracellular keratohyline granules synthesized (including profilaggrin)
- Lipids in lamellar granules secreted into intercellular space to form water barrier to keep water in skin
10
Q
Stratum Corneum
A
- In epidermis
- Nuclei and organelles degenerate, cells flatten
- Profilaggrin processed into filaggrin (help keep water in cells)
- Keratins (structural cytoskeletal proteins) combine with filaggrin into macrofibrils that help create protective layer
11
Q
Brick and mortar?
A
Stratum corneum
Brick- flattened keratinocytes filled with keratin and filaggrin
Mortar- lipid mixture surrounding keratinocytes providing water barrier
12
Q
Keratins
A
- In epidermis
-major fibrous structural proteins in hair/nails
-over 40+
-combine to form INTERMEDIATE FILAMENTS
(pairs differ by location in body)
-mechanically stabilize cell against physical stress
-have large amounts of sulfur-containing amino acid cysteine
13
Q
Melanocytes
A
- In epidermis
- Pigment-producing cells
- Derived from neural crest; migrate during embryonic development
- “live” along basal cell with about 1 per 10 keratinocytes
- transfer pigment to surrounding keratinocytes
14
Q
Langerhans Cells
A
- Dendritic cells in mid-epidermis
- Major immune players in skin
- Recognize abnormal antigen: take up, process, present to lymphocytes in regional lymph nodes
- Important in allergic rxns, tumor surveillance
15
Q
Merkel Cells
A
- In epidermis (basal layer)
- touch sensation
- develop in malignant tumors
16
Q
Dermis
A
- Support Layer
- Thickness Varies by site (1-4mm)
- Blood vessels/lymphatics, nerves, sweat/oil glands, hair follicles
17
Q
Fibroblasts
A
- In Dermis (main cell)
- Mesenchymal origin
- Responsible for synthesis and degradation of connective tissue proteins (collagen, elastin, glycosminoglycans)
- Injury to skin triggers mitosis of fibroblasts
- Responsible for wound healing/scar formatin
18
Q
Mast Cells
A
- In Dermis
- Part of immune system
- Specialized tissue cells rich in histamine and heparin granules
- Release their granules when triggered by injury or when bind to IgE Ab during allergic rxn
- Histamine and other mediators important in allergic rxns and wound healing “wheal & flare”
19
Q
Hair Follicle
A
- Extend through dermis into subcutis
- Each has associated sebaceous (oil) glands
20
Q
Pilosebaceous unit
A
- Hair follicle
- Sebaceous (oil) gland
- Apocrine sweat glands (in axilla and anogenital skin)
- Arrector pili muscle (goose bumps)
21
Q
Eccrine Sweat Glands
A
- “true”
- present throughout body
- open directly on skin (no hair follicle)
- function to regulate temp by evaporative cooling of sweat
22
Q
Subcutis
A
Fat layer that separates dermis from underlying fascia, muscle, organ
Serves as: Insulation, Energy, Protection from injury
23
Q
Sun Damage
A
Hurts Keratinocytes, failure to “delete” (apoptosis)
damaged cells can result in skin cancer
24
Q
Filaggrin Defect
A
Atopic dermatitis (barrier defects)
25
Epidermolysis Bullosa Simplex
Genetic mutations in Keratin 5/14
| -blister
26
Melanocytic Tumors
1) Nevus: benign
| 2) Melanoma: malignant
27
Functions of Skin
1) barrier
2) immune recognition/surveillance
3) damage repair
4) thermoregulation
5) photoprotection
6) communication
28
Barrier Function
-regulate water loss, protection from mechanical/chemical/microbial insults
If defective: dehydration, infection, injury of skin (ulcers), inflammation
29
Immune Regulation of Skin
Innate and adaptive
-can be involved and injured by immune function
Defective: infection, cancer, autoimmune/inflammation, allergic rxns
30
Autoimmune Bullous Diseases
- disorders of epidermal adhesion or cohesion mediated by autoantibodies to skin adhesion molecules
- characterized by erosions or blisters in skin (mucosa)
31
Pemphigus Vulgaris Ab?
Anti-Desmosome Abs
32
Bullous Pemphigoid Ab?
Anti-Hemidesmosome Abs
33
Repair Injury
Wound healing, repair DNA or apoptosis
| Defective: chronic skin ulcers, infection, cancer
34
Xeroderma Pigmentosa
skin cancer in childhood
35
Thermoregulation
-constant temp, insulation from fat and hair, control heat loss through sweat/changes in dense microvasculature
Defection: bad for health/confort, hypo/hyperthermia
36
Hypohiseoric Ectodermal Dysplasia
Genetic mutation in EDAR gene (ectodyplasin A receptor)
- protein critical for proper interaction b/w developing ectoderm and mesoderm
- abnormal hair follicels, sweat glands, teeth
- can't regulate temp: over heat
37
Raynauds' Phenomenon
- Chronic episodic attacks of digital ischemia
- Provoked by cold
- Painful, can ulcerate
- Can be associated with underlying autoimmune disease
38
Circulation Abnormalities
-diseases that injure blood vessels
-results in cutaneous necrosis/ulveration
Ex: Small vessel vasculitis
39
Skin Communication
touch, hot/cold, mechanoreceptors
Dysfunction: itch, dysesthetic pain/burning, hyperesthesia (sensitive skin), pain
Ex: Neuropathic ulcers, Trigeminal Trophic Syndrome
40
Photoprotection of skin
-epidermis has dark pigment (melanin), helps prevent against UV radiation
Dysfunction: cancer, burning
Ex: albinism
