Class 2- Cellular Injury, Inflammation, and Wound Healing Flashcards
Describe the three types of cellular injury
- Reversible
- Apoptosis and Programmed Cell Removal
- “peaceful” cell death
- Necrosis
- cell death
- cause inflammation
Mechanisms of Cellular Injury: Free Radical/ Reactive Oxygen Species (ROS)
- atom with unpaired electron
- causes “oxidative Stress”
- byproducts of normal metabolism but counteracted with antioxidants
- under stress antioxidants are overwhelmed
What are the causes of Free Radical/ROS
- mutations
- protein breakdown or misfolding
- membrane damage
Mechanisms of Cellular Injury: Hypoxic
- insufficient oxygen
- can be cognitive
- CP (from hypoxic injury near birth)
Mechanisms of Cellular Injury: Reperfusion Injury
- decreased oxygen perfusion (Ischemia)
- causes inflammation and free radical release
- occurs in brain or heart
Mechanisms of Cellular Injury: Chemical Injury
- drugs
- asbestos
- lead
- mercury (brain development)
- CO
Mechanisms of Cellular Injury: Physical Agents
- mechanical forces
- extreme temperature
- electrical forces
Other Mechanisms of Cellular Injury
- atmospheric pressure changes
- radiation
- environment (noise, sunlight)
Four Results of Cellular Injury
- mitochondrial damage (deceasing ATP)
- Cell membrane damage (Na+/K+ pump, increased water, Ca++ entry)
- Ribosome Damage (protein folding)
- DNA
Systematic Manifestations of Cellular Injury
- fatigue
- anorexia
- increased troponin
- malaise
- increase LDH
- triggers inflammatory response
- fever
- increased CK
Inflammatory Response to Cellular Injury
- second line of defence
- part of innate immunity
- rapid
- non-specific
- activated by cell injury or necrosis
Goals of Inflammatory Response
- prevents infection
- prevents further damage to other tissues
- contains bacteria
- limits/controls inflammatory process
- initiates adaptive immune response
- initiates healing
Five Local Manifestations of Inflammation
- Pain
- Swelling
- Heat
- Redness
- Loss of Function
Vascular Inflammatory Response
- blood vessel dilation
- increased vascular permeability
- fluid into tissues
- more viscous blood
- clotting
Cellulr Inflammatory Response
- WBC adherence to capillary
- WBC diapedesis (squeeze through capillary walls)
- WBC to injury (emigration)
- chemotaxis
- phagocytosis
What is Chemotaxis?
movement of a motile cell or organism, or part of one, in a direction corresponding to a gradient of increasing or decreasing concentration of a particular substance
Exudate Inflammatory Response
- fluid
- RBC
- WBC
- tissue debris
Acute Inflammatory Response
- neutrophils
- macrophages
- histamine
Systematic Manifestation of Acute Inflammation: Leukocytosis
- increased number of leukocytes
Systematic Manifestation of Acute Inflammation: Lymphadenitis
- enlarged lymph nodes
Systematic Manifestation of Acute Inflammation: Elevated Plasma Markers
- erythrocyte sedimentation rate (ESR)
- C-reactive protein
Describe Chronic Inflammation
- lasts over two weeks
- persistant irritant
- unsuccessful acute inflammatory response
- long-term
- self-perpetuation
- debilitating
- in phagocytic cells neutrophils die and lymphocytes are activated
- can further injure cells and delay healing
- fibroblasts and scar tissue form causing loss of function
- risks of cancer, CAD etc.
Systemic Manifestations
- low fever
- malaise
- fatigue
- anorexia
- leukocytosis
- lymphadenopathy
- increased ESR
- Increased C-reactive protein
- spleen hyperplasia
- anemia
- pain
- activity intolerance
- depression
- insomnia
- weight loss
Phase One of Healing
Inflammation
- neutrophils and macrophages clean injured area
- blood clot acts as scaffold
Phase Two of Healing
Proliferation and New Tissue Formation
- fibroblasts secrete collagen and growth factors
- new epithelial cells
granulation of tissue
Phase Three of Healing
Remodelling and Maturation
- scar tissue formation
- scar remodelling
