Wound Healing/Mini CPC Flashcards
**Name three classes of transmembrane signaling receptors and the intracellular signaling pathways that they usually activate.
- Kinase-coupled receptors
- -Most GROWTH FACTORS
- -Activates PI3, IP3, or MAP kinase pathways - Receptors without kinase activity
- -CYTOKINES
- -Act through JAK/STAT pathway - GPCRs
- -CHEMOKINES
- -Release Ca and/or generate cAMP
Diagram the cell cycle.
G0 - quiescent, stable cells G1 - growth S - DNA replication (cyclin E) G2 - more growth M - mitosis (division of nucleus) (cyclin B)
Explain how cyclins and cyclin-dependent kinases regulate the cell cycle.
Have checkpoints between every phase
CDKs produced constitutively, activated by cyclins
Cyclins made according to stage of cell cycle, as cell responds to outside stimuli
List the key cellular types involved in wound healing. (4)
Leukocytes: neutrophils and **macrophages
Endothelial cells
Epithelial cells
Fibroblasts
State the role of collagen type I as an ECM element.
Provide structure and strength, especially in scarring
State the role of collagen type IV as an ECM element.
STRUCTURAL NETWORK on which to attach things
–Looks like chain-link fence
State the role of fibronectin as an ECM element.
Adhesive glycoprotein
Functions in CELL ATTACHMENT and MIGRATION
–Very sticky
–Binds fibrin, heparan, collagen, integrin
State the role of laminin as an ECM element.
Adhesive glycoprotein
Functions in CELL ATTACHMENT
–Binds laminin, heparan, and cell
State the role of proteoglycans as an ECM element.
Include heparan, condrotin, dermatan sulfates
Functions in ECM WEAVING
Serves as reservoir for GROWTH FACTORS/CHEMOKINES
—Helps establish gradients of these
Explain the stages of scar formation from initial wound to collagen maturation.
- Induction of an inflammatory process in response to initial injury -> removal of dead/damaged tissue by neutrophils/macrophages
- Proliferation and migration of parenchymal and CT cells
- Angiogenesis and granulation tissue
- Synthesis of ECM proteins and collagen deposition
- Tissue remodeling
- Wound contraction
- Acquisition of wound strength
List the functions served by macrophages in wound healing. (4)
Play an essential role!!
- Recruitment and maturation
- Phagocytosis/killing of microorganisms (wound decontamination)
- Phagocytosis of tissue debris (wound debridement)
- GF release
Distinguish wound healing by primary vs. secondary intention.
Primary: something narrow (cut)
- Pull edges of wound together
- Very minimal scar
Secondary: for a larger area (scrape, burn, wide cut)
-Wound heals by deposition of a lot of collagen -> large scar -> contraction
Describe granulation tissue at the gross and histological levels.
Gross = watery looking tissue with tiny red dots
Histological =
- Lots of thin-walled capillaries
- *-Activated endothelial cells
- *-Highly activated fibroblasts (big angry purple cells, often with tails)
- *-Faintly basophilic ECM deposited
- Scattered neutrophils, macrophages, lymphocytes
List six systemic and four local factors that influence the success of wound healing.
Systemic:
- Nutrition (scurvy, protein deprivation)
- Metabolic status (diabetes is bad)
- Circulation (ischemia is bad)
- Hormones
- Genetic makeup
- Medical treatment (steroids are bad)
Local:
- Infection
- Foreign bodies
- Mechanical factors
- Size, location, type of wound
List and describe six pathological outcomes/complications of wound healing.
- Scar formation -> loss of function
- Keloid formation
- Desmoid (aggressive fibromatosis) - too much collagen deposition
- Ulceration, esp. in poor circulation (diabetes)
- Wound dehiscence (separation)
- Scar contraction - can be like a dense collagenous tether
Define scar. What does a mature scar look like histologically?
Collagenous type of tissue repair, whether diffuse or linear
Mature collagen! Very dense, parallel
- Few fibroblasts
- Few vessels
Define granulation tissue.
New connective tissue and tiny blood vessels that form on the surfaces of a wound during the healing process
The really immature connective tissue that is going to result in scar formation