Week 7 Quiz (Wound healing and alt. of Hematologic fx) Flashcards
1
Q
Resolution definition
A
- injured tissue is replaced by cells of the same type
- restoration of the original structure and function
2
Q
Repair definition
A
- destroyed tissue is replaced by connective tissue (scar)
- fills in lesion and restores tensile strength but can not carry out physiologic functions of the destroyed tissue
3
Q
when do resolution/repair occur?
A
they begin early during the inflammatory process
4
Q
Regenerative capacity of different cell types
A
- Labile cells
- Quiescent cells
- Permanent cells
5
Q
Labile cells and examples
A
- continuously dividing (proliferate thought life)
- skin, oral cavity, GI tract lining, urinary tract, bone marrow
6
Q
Quiescent cells and examples
A
- stable cells
- usually demonstrate low level of replication, but stimulation can lead to rapid increases in division
- bone, kidney, pancreas, fibroblasts, liver
7
Q
Permanent cells and examples
A
- nondividing cells
- stopped dividing during prenatal life
- nerve cells, cardiac m., skeletal m.
8
Q
Skeletal muscle fiber repair
A
- multinucleated, provide multiple copies of genes to speed up production of enzymes and structural proteins
- myoblasts: embryonic cells which fuse to create the muscle fibers
- satellite cells: assist with repair of damaged fibers = left-over myoblasts
9
Q
Other factors which influence wound healing
A
- site of the wound
- mechanical factors
- size of wound
- infection (won’t heal until get rid of infection)
- circulatory status (cartilage example)
- nutritional and metabolic factors
- age
10
Q
Tension lines
A
- most collagen and elastin fibers are in parallel bundles
- their orientation depends on the stress placed on the skin during normal movement
- clinical significance in surgery
11
Q
Debridement
A
- the first, absolutely essential step in wound healing is debridement
- “clean-up” of particulate matter in the inflammatory exudate by phagocytosis
- dissolution of fibrin clots by fibrinolytic enzymes
- natural debridement occurs, but is slow (inflammation and phagocytosis)
- surgical debridement speeds up healing
12
Q
First intention healing
A
- primary union
- wounds with minimal tissue loss
- example: sutured surgical wound
- always preferred if possible
- more likely to lead to resolution
13
Q
Second intention healing
A
- large, open defects and infected wounds
- examples: degloving injuries, burns
- formation of granulation tissue
- more likely to lead to repair
14
Q
Healing by second intention involves
A
- formation of a healthy granulation bed (happy pink)
- filling in the wound defect
- covering or sealing the wound (epithelialization)
- shrinking the wound (contraction)
- wound maturation
- remodeled (scars)
15
Q
granulation tissue
A
- has a soft, pink, granular appearance
- represents a temporary scaffolding that changes over time
- contains angioblasts and fibroblasts
- angioblasts are cells that form new blood vessels
- fibroblasts form collagen fibers for strong scar tissue
16
Q
Repair involves and occurs in what two phases?
A
- filling in the wound defect
- epithelialization (covering or sealing the wound)
- contraction (shrinking the wound)
- reconstruction phase
- maturation phase (think about us remodeling)
17
Q
Epithelialization
A
- epithelial cells from the surrounding healthy tissue migrate onto the granulation bed
- use proteolytic enzymes to sever the connection between the clot and the wound surface and slide in between
- make contact with similar cells from all sides of the wound and seal it (contact inhibition allows the cells to meet up and say they are done sealing)
- epithelialization can be aided by keeping the wound moist
18
Q
Phases of wound healing
A
- inflammation
- granulation tissue
- wound contraction
- collagen accumulation remodeling starts near the end of granulation tissue phase
19
Q
Reconstructive phase
A
- wound is initially sealed off by a blood clot containing fibrin and trapped cells
- debridement by macrophages and neutrophils (or by a surgeon)
- chemical mediators of inflammation are secreted by macrophages and promote growth and activity of angioblasts, and fibroblasts
- granulation tissue forms in 2-5 days
20
Q
Angiogenesis
A
- capillary buds sprout out of vascular endothelial cells on wound margins
- new endothelial cells migrate into the scaffolding and organize into vessels
- allows influx of blood with oxygen, nutrients, and more phagocytic cells and chemical mediators
- also called neovascularization
21
Q
Fibrosis (Fibroplasia)
A
- fibroblasts enter the area and proliferate
- they deposit fibrous structural proteins
- fibroblasts produce collagen which gradually develops more strength (scar tissue made of collagen and there are several types of collagen)
- collagen not inside of cells
- original collagen that is laid down is later replaced by better collagen that is more parallel to tension lines
22
Q
wound contraction
A
- myofibroblasts have features of both fibroblasts and smooth muscle cells
- the myofibroblasts establish connections with neighboring cells
- they anchor themselves to the wound bed and exert pull on neighboring cells
- contraction alone may move the wound edge by 0.5mm per day (just like a muscle)
