Session 3 - Wound Healing Flashcards
this is the process by which the cells in the body regenerate and repair to reduce the size of a damaged or necrotic area
healing
what are the two processes involved in healing?
removal of necrotic tissue (demolition) and the replacement of this tissue; remove and replace
what is defined as the process by which necrotic cells are replaced by the same tissue as was originally there?
regeneration
what is the process by which injured tissue is replaced with scar tissue?
repair
T or F: most often.healing proceeds through collagen deposition or scarring (fibrosis).
TRUE
T or F: tissue regeneration is favored when the matrix composition and architecture are unaltered
TRUE
T or F: wounds that do NOT heal may relfect damage to the tissue architecture by reduced protease activity, decreased matrix accumulation, or altered matrix assembly.
FALSE: all are true except that it’s EXCESS protease activity; remember, when you have fibrosis or scarring is when there is reduced protease activity and increased matrix accumulation
what is released by platelets that help to facilitate repair?
platelet derived growth factor (PDGF)
what is released from mast cells which help to promote BV formation?
heparin
what are the 3 phases of wound healing?
- inflammatory phase 2. proliferative phase 3. remodeling phase
what happens to platelets after they are exposed to endothelial damage? (think of the steps taken to limit blood loss)
aggregate, add fibrin, form a thrombus.
in which stage of wound healing is there a release of chemical factors such as growth hormones?
inflammatory phase
the permeability of post-capillary venules increases due to ____ cells contracting while the ____ junctions retract. these factors allow for “inflammatory edema”
endothelial; inter-cells
at first, the fluid in “inflammatory edema” is considered transudate or exudate? as time proceed does the characterization change or stay the same?
transudate; becomes exudate
neutrophils or macrophages - these are responsible for cytokine release.
macrophages
lymphocytes or macrophages - these have a role in cell-mediated immunity.
lymphocytes
these specialized cells are responsible for the formation of granulation tissue, synthesis of collage and contraction of wounds
fibroblasts
in acute inflammation which cells appear first, followed by which?
neutrophils followed by macrophages
in simple chronic inflammation, which cells type is present most in numbers? followed by?
lymphocytes, followed by plasma cells and macrophages
in granulomatous chronic inflammation, which cells are more numerous?
macrophage clusters, followed by peripheral lymphocytes
as a mediator of acute inflammation, histamine is responsible for v/d or v/c?
v/d.
what is IL-1 responsible for activating?
macrophages and fever
what is IL-8 responsible for in the mediation of acute inflammation?
chemotaxin for polys
locomotion of the rapidly migrating leukocytes is powered by what? slower moving cells such as fibroblasts move via what?
lamelipodia; filopodia
what is a prominent early feature in injured tissue that serves to replace damaged cells?
cellularity (cell proliferation)
what is the name of a specialized vascular tissue that is formed transiently during repair?
granulation tissue
T or F: cells that are terminally differentiated do NOT contribute to repair or regeneration.
TRUE - such as myocytes, neurons.
healing by primary or secondary intention: a wound with minimal tissue loss
primary
healing by primary or secondary intention: wound requires contraction and extensive cell prolideration
secondary
healing by primary or secondary intention: result is small scar
primary
during the maturation phase of wounding healing, what happens to unnecessary vessels formed in granulation tissue?
removed by apoptosis
T o F: the maturation phase of wound healing can last as long as a year.
TRUE
what is the initial phase of wound healing? (following v/c and involves platelets adhering to damaged endothelium and discharging ADP)
hemostasis
what is the second phase in the evens of wound healing?
inflammation
there is an early, mid, and late phase involved in the repair of skin - in which phase will you find the following: thrombosis, inflammation, and re-epithelialization.
early
in which phase of the repair of skin will you find granulation tissue formation and contraction?
mid
in which phase in the repair of skin will you find the following: remodeling, and accretion of final tensile strength?
late
this is the transient, specialized tissue of repair which replaces the provisional matrix.
granulation tissue
T or F: a key step in the development of granulation tissue is the recruitment of monocytes to the site of injury by chemokines.
TRUE
granulation tissue eventually transitions to what? (this is the balance between collagen synthesisi and collagen breakdown)
scar tissue
what is it that remains active at the site of a wound increasing the density of a scar over time?
fibroblasts
this is the physiological process involving the growth of new blood vessels from pre-esiting vessels.
angiogenesis
what is the term for when there is spontaneous blood vessel formation?
vasculogenesis
what is the term for new blood vessel formation by splitting off existing ones?
intussusception
T or F: angiogenesis is a NORMAL process in growth and development as well as in wound healing.
True
T or F: granulation tissue has more capillaries per unit volume than any other tissue
True
when new blood vessels form de novo from angioblasts, what is this process called?
vasculogenesis
how does the epidermis constantly renew itself? (via mitosis of what cells in which layer of skin)
kerinocytes of the basal layer
T or F: in terms of re-epithialization, maturation requires an intact layer of basal cells that are in direct contact with another and the basement membrane
TRUE
in terms of wound contraction, which cell is it that reacts like a smooth muscle?
fibroblasts - the myofibroblast is the cells response for wound contraction.
which cells are responsible for the deforming pathological process termed would contracture?
myofibroblasts
what is the renewal of a damaged tissue or a lst appendage that is identical to the original one?
regeneration
the power to regenerate tissue is derived from a small number of unspecialized cells known as what?
stem cells
in terms of complications of wound healing, if the injury sections or destroys the ______ layer of the stratum corneum, a scar will ALWAYS form.
papillary layer
keloid or hypertrophic scare: continues to enlarge beyond the original size and shape of the wound.
keloid - a hypertrophic scar enlarge within the confines of the original wound
T or R: keloids and hypertrophic scars are both raised above the skin level
TRUE
T or F: hypertrophic scars are self-limited.
true
what eventually happens to the general appearance of hypertrophic scars?
they become pale and flat over time
what is the main difference btwn keloids, hypertrophic scars and widened scars?
widened scars are flat and sometimes depressed
what is it called when the normally elastic connective tissues are replaces by inelastic fiber like tissue
contracture
what is the most common cause of contracture?
scarring and lack of use (due to immobilization or inactivity)
what is the best tx option for contracture?
PT
what is contracture a serious complication of?
bruns
what is the term that describes a rupture or splitting open, as of a surgical wound or of an organ or structure to discharge its contents?
dehiscence
what type of surgeries are most commonly associated with a higher incidence of wound dehiscence?
abdominaal
what is the appearance of the dermis when a keloid is present? (under the microscope)
thickened by the presence of collagen bundles
