Inflammatory Process Flashcards
Cell atrophy
decrease in cell size to use less nutrients
Cell hypertrophy
increase in cell size - muscle building
Cell hyperplasia
Increase in number of cells (growing, uterus)
Cell metaplasia
change in cell type
Necrosis causes and effects
loss of blood supply exposure to toxins cellular swelling protein denaturation tissue dysfunction
Apoptosis
programmed cell death; dead cells are removed with minimal disruption of surrounding tissue
Hypoxia
oxygen deprivation
ischemia
loss of blood supply
due to impeded arterial flow or reduced venous drainage
Causes of hypoxia
ischemia
inadequate oxygenation (pneumonia, emphysema)
reduced oxygen carrying capacity (anemia)
Causes of cell injury
- oxygen deprivation
- chemical agents
- infectious agents
- genetic defects
- immunologic reactions
- nutritional imbalance
- physical agents
- aging
Response to injurious stimuli depends on
type of injury
duration
severity
Immunologic reactions can cause cell injury by
anaphylactic shock - exaggerated response
auto-immune disease
Auto-immune disease is loss of
self tolerance
Tolerable time of complete ischemia without irreversible injury: skeletal muscle
2-3 hours
Tolerable time of complete ischemia without irreversible injury: cardiac muscle
20-30 mins
Tolerable time of complete ischemia without irreversible injury: brain
4-5 mins
Why does aging contribute to cell injury?
imperfect restoration of structure or function
cellular senescence
reduced immune strength
shorter telomeres
Inflammation definition
a protective response intended to eliminate the initial cause of cell injury as well as the necrotic cells and tissues resulting from the original insult
Benefits of inflammation
helps clear infection
makes wound healing possible
Negative to inflammation
potential to cause harm (heaves, asthma, anaphylaxis, etc)
Acute inflammation
delivers leukocytes to injury site
Leukocytes
clear any invading microbes and begin the process of cleaning necrotic tissue
5 classic signs of acute inflammation
heat redness swelling pain loss of function
2 components of acute inflammation
vascular changes
cellular events
vascular change in acute inflammation
vasodilation
cellular events in acute inflammation
cellular recruitment and activation
Types of leukocytes
Neutrophils
Eosinophils
Basophils
Neutrophil activity and death
forms pus
Eosinophils primarily deal with
parasitic infections
Basophils release
histamine, causing inflammation
Basophils are chiefly responsible for
allergic and antigen response
B cells and T cells are
Lymphocytes
Monocyte functions (2)
phagocytosis
present pathogen pieces to T cells for memory or so antibody response may be mounted
Macrophage function
phagocytosis
Macrophages develop from
monocytes
Vascular and cellular changes - acute inflammation (6)
- initial vasoconstriction
- vasodilation
- increase vascular permeability
- Leukocytes arrive
- Leukocytes release chemical mediators
- phagocytosis
Steps to stop bleeding
platelet aggregation > blood coagulation > clot
redness and heat of inflamed area is caused by
histamine
Blood becomes
more viscous
Why does circulation slow and blood viscosity increase?
So that cells can leave the blood vessel and go to injury site
Leukocytes (neutrophils) will transmigrate through ____________ to ____________
intercellular junction
extracellular matrix
Describe phagocytosis
Leukocytes engulf the injurious particle and degrade it. This can kill bacteria and clean up dead cells.
Outcomes of acute inflammation (3)
- resolution
- scarring/fibrosis
- progression to chronic inflammation
Resolution
limited or short lived injury
minimal tissue damage
tissue replaces any dead cells with perfect new cells
Scarring/Fibrosis
substantial tissue damage
non-regenerating tissues
cases of abscess formation
Chronic inflammation
persistent viral or bacterial infection prolonged exposure to potentially toxic agents autoimmune disease can lead to regeneration or fibrosis anti-inflammatories necessary
angiogenesis
new blood vessel formation
infarction
death of tissue due to lack of oxygen due to an obstruction in blood supply
extracellular matrix (ECM) critically regulates
the growth, movement and differentiation of cells
Roles of ECM
- mechanical support
- determination of cell orientation
- control of growth
- organized regeneration of tissues
Components of ECM
collagen
elastin
glycosaminoglycans
hyaluronic acid
purpose of collagen in ECM
tensile strength
purpose of elastin in ECM
recoil and return to baseline structure
what are glycosaminoglycans and hyaluronic acid?
highly hydrated compressible gels conferring resilience and lubrication
Fibrosis
in severe or persistent injury, repair occurs by replacement of what should be normally functioning cells with connective tissue.
components of granulation tissue
angiogenesis
fibroblasts
loose ECM
What is granulation tissue highly populated with and what do they do?
macrophages
clear debris and allow for fibroblast proliferation and ECM production
First intention
clean, uninfected surgical incision
cells are regenerated w/ normal function
scar is minimal
Second Intention
open wound, abscess, ulceration
extensive growth of granulation tissue
fibrotic scar formation
Wound strength compared to unwounded tissue
sutured: 70%
suture removed: 10%
after 3 wks: 70-80%
Acute inflammation is essential to
the normal outcome of wound regeneration/repair
Healing by ______ intention is better than by _______ intention
first
second
Abscesses leave a scar….
always
If inflammation becomes chronic, it contributes to the…
pathogenesis of the disease, excessive fibrosis and scarring
