Concepts of Disease + Cellular Injury Flashcards
Cellular adaptation
- cells must adapt to internal and external environmental changes
- may change change size or form, but still functions normally
- may be temporary or permanent, based on timeline
examples of adaptation
- atrophy
- hypertrophy
- hyperplasia
- metaplasia
- dysplasia
Atrophy usually affects what tissue?
muscle tissue
How does Atrophy affect cells?
its a decrease in cell size
Atrophy causes?
- disuse
- denervation (nerves supplying tissue stop working)
- decrease in nutrition
- hormone imbalance
- lack of blood or oxygen flow
Hypertrophy usually affects what tissue?
muscle tissue: cardiac and skeletal
How does Hypertrophy affect cells?
it is an increase in cell size
Hypertrophy cause?
increased work demand on cells
Hypertrophic physiologic reason?
exercise - weight lifting, running, etc.
Hypertrophic pathologic reason and 2 types
disease
- adaptive
- compensatory
Compensatory hypertrophy?
one organ increases in size to make up for loss of the other
ex: lose a kidney and other enlarges to make up for its function
Adaptive hypertrophy?
some sort or resistance in the body causes tissue to work harder
ex: myocardial hypertrophy
Hyperplasia affect on cells
increase in number of cells
Hyperplasia can be a normal response to?
tissue removal
ex: liver regeneration
What cell types do hyperplasia affect?
labile or stable cells
- skin, liver, skeletal
Metaplasia occurs when…
we look at a specific area of the body and see a different type of cell than expected
T/F - metaplasia can cause different tissue types to form
False - cell type changes, but tissue type does not
Same umbrella of tissue
example: simple cuboidal epithelium–> simple columnar
NOT simple cuboidal epithelium –> reticular connective tissue
Metaplasia causes?
chronic irritation or inflammation
Dysplasia occurs when…
we look at an area of cells under the microscope and see disorganized sample
- different levels of maturity, shape, etc.
Dysplasia is a future predictor of…
cancer (beginning stages)
Intracellular accumulations 3 general categories
- abnormal amounts of normal substances (ex: bilirubin)
- abnormal endogenous substances (normal substance in wrong place in body)
- foreign or exogenous products (external)
Causes for intracellular accumulation
- metabolism problems
- organ dysfunction
- genetic disorders
What is tissue calcification and what are the 2 types?
- abnormal deposits of calcium and other minerals into the tissues
- dystrophic
- metastatic
Dystrophic tissue calcification occurs when…
a group of injured or dying cells in a particular location die, open up, and release their contents into the surrounding area
Dystrophic tissue calcification results in…
a LOCALIZED deposit of calcium in that area of tissue
Dystrophic tissue calcification effects:
the large, visible deposit causes damage to surrounding tissue and causes stiffness in that area
- stiff movement –> cant close valve properly
Where can dystrophic tissue calcification be seen?
seen in people with atherosclerosis and healed TB lesions
Metastatic tissue calcification occurs when there is…
elevated calcium concentration in the blood
Is Metastatic tissue calcification localized or systemic?
systemic
Metastatic tissue calcification levels can get so HIGH/LOW that it causes…
Can get so HIGH that it causes microscopic calcium deposits in tissues
Dystrophic vs. Metastatic tissue calcification
Dystrophic causes more significant tissue damage, but Metastatic is more widespread
What are the 5 Types of cellular injury?
- Physical injury
- Radiation exposure
- Infectious/biologic agents
- Chemical agents
- Deficiency of critical nutrients
Types of Physical cellular injuries
- blunt force
- sharp force
- temperature
Blunt force physical cellular injury definition and examples
- tissue is crushed, sheared, or torn
Examples:
- contusions (bruises)
- hematomas (blood pockets)
- abrasions (scrapes)
- lacerations
Sharp force physical cellular injury definition and examples
- large amount of force applied to a smaller area of tissue
Examples:
- Stab wounds
- Puncture wounds
- Incised wounds
Lacerations vs. incisions
Lacerations are accidental
Incisions are precise, clean - surgical
2 types of Temperature physical cellular injuries
- heat injury (low intensity and high intensity)
- cold injuries
Low intensity Heat injury
- occurs in extremities
- damages small blood vessels
- disrupts enzyme activity
- damages cell membranes
- some cell death, blisters, not deep
example: hit elbow on stove, sunburn
High intensity Heat injury
- occurs in extremities
- worse damage to blood vessels
- coagulation of proteins
example: electrical burns, exposure to open flame
Cold temperature injuries can cause:
reduced blood flow
- increased blood viscosity (blood thickness)
- vasoconstriction (tightening of blood vessels)
frostbite
- freezing can form ice crystals in tissue
Ionizing Radiation exposures
- above normal UV range
- gamma rays
- can displace electrons and potentially alter DNA
examples: X-rays, nuclear bombs
Non-ionizing Radiation exposures
- below visible spectrum
- can generate heat
ex: microwaves
What is Hypoxia?
reduced oxygen in the cells
Causes of localized and systemic hypoxia
localized - COPD, asthma, high altitude
systemic - problem with arterial blood flood to tissue
What disorders can cause hypoxic cellular injury?
oxygenation - problem with gas exchange
perfusion - adequate blood flow to any area
Predictable steps when O2 is low (hypoxia)
- Effect on metabolism/ ATP, and Na/K+ pump
- Aerobic metabolism cannot function without O2, so it becomes anaerobic metabolism
- ATP production is slowed
- Nasty byproducts of anaerobic metabolism cause a buildup of lactic acid, and then acidosis
- Na/K pump halts –> increase in Na –> increase in H2O –> cell swells –> cell lyses –> cell membrane dies
What is Ischemia?
impaired arterial blood supply to a specific area of tissue
blood flow or O2 reduction
Ischemia is the most common cause of…
localized hypoxia
- low blood supply/O2
Does Ischemia cause tissue death? Why or why not?
No
- since blood supply is not completely cut off, the tissue is simply injured, not dead
Ischemia is reversible IF…
blood flow is restored to the area QUICKLY
What is the most common cause of Ischemia?
atherosclerosis
- slow build up of plaque lesions inside artery leads to the artery being choked off
- not enough cross sectional areas for normal blood flow
What is Infarction? What is it caused by?
- PERMANENT tissue death
- caused by the sudden and complete stoppage of arterial blood
- total lack of oxygen
Is Infarction localized or systemic? What is an example?
localized
ex: myocardial infarction –> stroke
What is Necrosis? What causes it?
- dead cells in an overall living person
- entire person is not dead, only a section of cells/tissue is
Caused by:
- Unregulated cell digestion by enzymes –> products are released into extracellular space –> localized inflammation
Cells + tissues that die may…
- may undergo liquefaction
- if enough protein retained: coagulation
Apoptosis vs. Necrosis
Apoptosis: orderly, programmed cell death due to cell maturity, growth, or turnover
Necrosis: messy, unplanned cell death due to injury of disease
Fate of necrotic tissue in smaller area
demolished + removed by phagocytosis
Fate of necrotic tissue per tissue type
- can regenerate based on tissue type
- if more advanced: scar tissue forms
Fate of necrotic tissue if Gangrene in extremities
dead tissue may slough (fall) off
Fate of INTERNAL necrotic tissue
may be encapsulated w/ fibrous connective tissue and then calcified
What is Gangrene? What is it caused by?
- a large macroscopic area of necrosis
- caused by deprivation of blood supply (not complete blockage)
What type of bacteria is associated with gangrene, and what is it’s function?
Saprophytic bacteria
- grows over dead tissue, digests it, and breaks down substance
Tissue/skin integrity is compromised when…
tissue death is on surface
especially in extremities
Dry Gangrene characteristics
tissue becomes:
- dry
- wrinkly
- changes color to a dark brown/black
line of demarcation: clear line between dead and healthy tissue
Dry Gangrene is caused by:
ARTERIAL blood blockage w/ no interference of venous return
Dry Gangrene is most commonly located in…
the extremities (feet - most peripheral point)
Wet Gangrene characteristics
- tissue is cold, swollen, and dark
- may have blebs on surface (fluid filled blisters)
- foul odor due to bacterial differences
Wet Gangrene is caused by:
interference with VENOUS return
Wet Gangrene can occur after
severe burns
Wet Gangrene may be located in…
internal organs OR extremities
Which is more dangerous: Wet or Dry Gangrene?
Why?
Wet gangrene is considered more dangerous
- moves through the body and takes over healthy tissue quicker than dry
- progresses quicker + can become systemic
Which of these are reversible and which are permanent:
- Cellular changes (atrophy, hypertrophy, hyperplasia, metaplasia, dysplasia)
- Cellular damage (hypoxic injury, ischemia, infarction, necrosis, dry/wet gangrene)
- Cellular injury (physical, radiation, infections, chemical, nutrient deficiency)
Reversible:
- atrophy, hypertrophy, hyperplasia, metaplasia, dysplasia
- hypoxic injury, ischemia
Permanent:
- infarction, necrosis, wet/dry gangrene
