Phases of healing Flashcards
Necrosis
The active degradation of death cells; end of pathologic process
Caused by injuries, infections, diseases, lack of blood flow, + extreme environment conditions
Need to be removed before healing can begin
Induces inflammation=danger signal
Types of necrosis
-Coagulative
-Caseous
-Liquefactive
-Fatty necrosis
-Fibrinoid
Coagulative necrosis
-Cause: Ischemia (lack of blood supply)
-Effect: Cell membrane preserved, nucleus undergoes pyknosis and karolysis (dissolution); organelles dissolve
-Areas: Solid internal organs (heart, liver, kidneys)
Caseous (Cheesy) necrosis
-Cause: TB; seen with other fungal infections
-Effect: Cell memb. destroyed; debris appears cheeselike and doesn’t disappear by lysis, persist indefinitely walled off in a fibrous calcified area forming a granuloma
Areas: Lungs, bronchopulmonary lymph nodes, skeletal bone (extrapulmonary TB)
Liquefactive necrosis
-Cause: Pygenic bacteria (Staphylococcus aureus)
-Effect: Death of neurons; lysosomes liquefy area, leaving pockets of liquid and cellular debris; shapeless amorphous debris remains
-Areas: Brain tissue (infarcts); skin, wound, joint infections
Fatty necrosis
-Cause: Acute pancreatitis, abdominal trauma
-Effect: formation of calcium soaps by the release of pancreatic lipases
-Areas: Abdominal area
Fibrinoid necrosis
-Cause: Trauma in blood vessel wall
-Effect: Plasma proteins accumulate; cellular debris and serum proteins form pink deposits
Areas: Blood vessels (tunica media, smooth muscle cells
Apoptosis
Programmed cell death, genetically mediated in a managed process that causes cells to die (TRIGGER/STIMULUS)
Physiologic
*NOT RELATED WITH INFLAMMATORY RESPONSE
During the remodeling phase, what is the maximal strength healing dermis attains?
80%
What type of tissue heals by regeneration?
epidermis
Proliferative phase of wound healing hallmark
New capillaries are created
Structural network that supports and surrounds cells within connective tissue
Extra cellular matrix
Neutrophil cell is responsible for:
ingesting debris and bacteria
Acute Inflammation
-Sudden and short duration of inflammation
-Exudation of fluid and plasma proteins (edema) and migration of leukocytes (neutrophils)
Chronic Inflammation
-Inflammation that doesn’t resolve but persists over time
-Presence of lymphocytes and macrophages, the proliferation of blood vessels and fibrosis, and tissue destruction
Clinical manifestations of inflammation
-Redness
-Swelling
-Increased temperature
-Pain
-Decreased function of the affected site
What causes the redness and heat during inflammation?
arteriolar vasodilation
What causes the swelling during inflammation?
the exudation and leukocyte infiltration
What causes the loss of function and pain during inflammation?
increased pressure from the edema on the peripheral nerves
In the presence of what does chronic inflammation occur?
extensive necrosis or if regeneration of parenchymal cells is not possible
T/F Inflammatory reaction may become chronic if underlying cause is not addressed.
True; injurious agent persists for a prolonged period
Repeated episodes of acute inflammation in the same tissue over time causes what?
Chronic inflammation
Chronic inflammation develops…
Common morphologic features of granulation tissue, macrophages, lymphocytes, and plasma cells
Acute Inflammation results in either…
Restitution of normal structure and function; if labile or stable cells or little necrosis occurs after injurious agent removed OR
Persistent abnormal structure and (possibly) function; if permanent cells or extensive necrosis is organized in scarring
Cellular Aging
Aging and age-related changes can significantly influence homeostasis and the recovery process
What does age-associated cell deterioration lead to?
leads to tissue or organ weakness aging or disease
What does the cell’s recovery depend on for recovery?
healthy cells
What is the prime target of age-related changes?
Mitochondrial DNA
What is the most well-described age associated change in postmitotic cells?
Presence of lipofuscin; an aging pigment granule found in high concentrations in older cells
Why is lipofuscin suspected to interfere with cellular function?
pressure from pigmented lipid on the cells nucleus
Free radical theory of aging
Excess amounts of free radicals causes DNA damage and cellular oxidative stress
Telomere aging clock theory
Telomeres at the end of chromosomes act as a molecular clock signaling the onset of cell senescence (deterioration)
Accumulation of these cells contributes to the aging process (Does NOT cause it)