Intro - cells, levels, wound healing Flashcards
1
Q
Skin receives ___ resting cardiac output
A
1/3 resting cardiac output
2
Q
Skin is composed of ___
A
connective tissue
3
Q
Skin Function
A
- Thermoregulation: sweating, vasodilation, vasoconstriction
- Sensation
- Metabolism of Vit. D
- Protection from shear
- protection from water loss
- body image, expression
4
Q
3 main layers
A
- Epidermis
- Dermis
- Subcutaneous/hypodermis
5
Q
How does epidermis receive nutrients?
A
Avascular, by diffusion from the dermis
6
Q
Langerhan’s cells location
A
Epidermis
Stratum spinosum
7
Q
Layers of the Epidermis
A
- Stratum Corneum
- Stratum Lucidum
- Stratum Granulosum
- Stratum Spinosum
- Stratum basale
8
Q
Keratinocytes
A
- skin cells
- majority of epithelial cells
- Accumulate keratin: vital for water loss control through the skin
- attracted to injured area by neutrophils and advance in a sheet to resurface area
- cannot bridge the gap, so roll under at edges of full thickness
- Majority in stratum spinosum
9
Q
Corneocytes
A
- differentiated keratinocytes surrounded by cornified envelope
- Outermost keratinocytes
10
Q
Langerhans Cells
A
- Contain distinctive granules
- “probably” monocytic in origin (WBC)
- Involved in cutaneous delayed hypersenstivity
11
Q
Melanocytes
A
- Produces skin pigment
- between/beneath basal layer
- synthesizes melanin from Tyrosine
- branches reach up through layers and squirt out the pigmentation
12
Q
Merkel Cells/Discs
A
- mechanoreceptors attached to keratinocytes that provide sensation to light touch
- touch receptor cells
- Disc: dermis
- Cell: epidermis
13
Q
Epidermal appendages: Hair Follicles
A
- regulates temperature by trapping air between hair and skin’s surface
- Lines with epidermal cells that regenerate epidermis after abrasions
14
Q
Epidermal Appendages: Sebaceous glands
A
- attached to hair follice
- lubricates skin and hair
- protects skin from bacteria with sebum
15
Q
Epidermal Appendages: Sudoriferious glands
A
- everywhere but lips and ears
- secretes sweat
16
Q
Epidermal Appendages: Nails
A
- originate from basal layer
- protects tips of digits
17
Q
Stratum Corneum
A
- flat dead cells filled with keratin
- shed, replace, repeat
- barrier to heat, light, bacteria, and some chemicals
- dryness inhibits bacterial growth
18
Q
Stratum Lucidum
A
- palms and soles of feet
- clear fat dead cells
- contains eledin: transforms into keratin
- replaces she stratum corneum
19
Q
Stratum Granulosum
A
- 3-5 rows of flattened cells
- Contains keratohyalin: precursor to waterproofing protein keratin found in above layers
20
Q
Stratum Spinosum
A
- multiple rows of polyhedral cells
- Contains: keratinocytes, merkel cells, langerhan cells
- attached together my desmosomes
21
Q
Stratum Basale (Germinativum)
A
- site of new cell production
- single row of keratoncytes connected by hemadesmosomes
- nails arise to protect tips of digits
22
Q
Basement membrane
A
- attaches epidermis to dermis
- Comprised of type IV collagen fibers
- filters substances moving from dermis to epidermis
23
Q
Dermis Functions
A
- Contains: sensory organs, vasculature, epidermal appendages, cells to protect against infection
- thickest layer
- gives skin the bulkiness (turgor) - 2-4 mm
- produces collagen and elastin for skin
24
Q
Dermis Cells
A
- Fibroblasts
- Macrophages
- WBC
- Mast Cells
- Sensory Receptors
25
Fibroblasts
- produce collagen and elastin
- crucial in wound healing
- lay down ground work for healing
26
Papillary Region
- Top 1/5 of dermis
- finger-like projections into epidermis
- allows for capillaries to get more blood into epidermis
- allows for nutrient/o2 exchange
- Contains Meisner's corpuscles: touch sensors
- Loose connective tissue and elastin
27
Reticular Region
- dense - connective tissue, collagen, elastin
- contains adipose, follicles, nerves, oil glands, ducts of sweat glands
- provides strength and elasticity to skin
28
Subcutaneous/Hypodermis
- Fibers extend through to anchor skin
- contains deep blood vessels and nerve endings
- Adipose layer
29
Adipose Functions
- White/pale yellow = healthy
- dark color = chronic wound
- Insulates
- Energy reserve
- Cushioning
- Storage for vitamin A, D, E, and K
30
Deep Tissue Contains...
- Muscle
- Tendon
- Ligament/Joint capsule
- Bone
31
Depths of Wounds
- Superficial
- Partial Thickness
- Full-thickness
32
Superficial Wound Tissues involved
Epidermis
33
Superficial Wound Example
First-degree burn
34
Partial Thickness Tissues Involved
Epidermis
| Dermis
35
Partial Thickness Examples
- Second-degree burns
- Stage II pressure ulcer
- Wagner grade 1 ulcer
36
Full thickness wound tissues involved
- Epidermis
- Dermis
- Subcutaneous tissue
- may be into deep tissue layers
37
Full thickness wound exmaples
- third degree burn
- Subdermal/4th degree burn
- Stage III pressure ulcer
- Wagner grade 2-5 ulcer
38
Effects of Aging
- Dermal thickness
- Fatty layer
- Collagen and elastin
- sensation and metabolism
- sweat glands
- circulation
- epidermal regeneration
39
Phases of Wound Healing
- Hemostasis*
- Inflammatory
- Proliferative
- Remodeling
40
Signs of Inflammation
- Redness
- Pain
- Temperature
- Swelling
- Loss of function
41
Time frame of Inflammation Stage
Time of injury --> 3 to 7 days
42
Inflammation Stage
- 11 proteins in plasma migrate to site of wound
- proteins and phagocytic defense mechamisms migrate from intervascular to extravascular
- Hemostasis: vasoconstriction, platelet aggregation, clot formation from thromboplastin
43
Inflammation - Margination
Leucocytes tend to occupy the periphery and adhere tot he endothelial cells that line the blood cells
44
Inflammation - Vascular Response
- Transudate produces local edema
- Blood vessels constrict to reduce blood loss
- Platelet aggregation
- Activated platelets release chemical mediators
45
Hemostasis
Immediate after injury
- vasoconstriction
- platelet aggregation
- clot occurs
46
Polymorphonuclear Leukocytes (PMNs)
```
-neutrophils
Scavengers
-Kill bacteria
-clean wound
-Secrete inflammatory mediators and MMPs (collagen formation)
```
47
Neutrophils
- First to injury site, most prevelent WBC at injury site
- cleanse wound
- pus = dead neutrophils
- lasts as long as needed based off of bacteria count
48
Lysozyme
- released by neutrophils
- enzyme
- produces free radicals to destroy bacteria
49
Eosinophil
- Allergies
- larger nucleii
- motile phyagoctyes
- anti-parasitic function
50
Basophils
- allergic reaction
- mast cells after leaving bloodstream
- release histamine
- promote fibroblast proliferation and mitosis by release of a mitogen
51
Histamine
- causes vascular dilation
- increased blood perfusion
- temporary edema
- stimulates collagen formation and healing
52
Macrophages
- largest formed element
- phagocytic - ingest bacteria
- cleans up cellular debris after an infection
- drawn to inflamed tissue by chemotaxis
53
Proliferation
- Angiogenesis
- Granulation Tissue Formation
- Wound contraction
- Epithelialization
54
Goal of Proliferation
- Fill in wound defect with new tissue
| - restore skin integrity
55
Proliferation time fram
3-5 days post injury up to 3 weeks (primary intention)
56
Angiogenesis
- capillary buds extend to wound bed
- endothelial cells create capillaries with loose junctions
- collagen synthesis by fibroblasts
- "new blood cell formation)
