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Risk factors
Increases the chances / likelihood of a patient developing a disease
2 categories:
Nonmodifiable
Modifiable
Age
Sex
Environment
Lifestyle
Hereditary
What are some cell stressors?
Hypoxic Injury (lack of oxygen) (most common)
Unintentional / intentional physical trauma
Oxidative stress
Too many free radicals
Things that lead to an increase in free radical formation include:
Prolonged exposure to ionizing radiation, UV rays, and X rays
Lead to the body making too many free radicals and they can lead to cell injury
Nutritional imbalances
Not getting enough of the essential nurtrients
Excess in saturated fats (atherosclerosis)
Excess in sugar (type 2 diabetes)
Deficiencies
Anemia = iron, Vit B9, B12
Scurvy = Vit C
Beriberi = Vit B1 [thiamine]
Pellagra = Vit B3 [Niacin]
Kwashiorkor’s = protein deficiency
Marasmus = low all macronutrients
Chemical Injury
Exposure to toxic chemicals (ex. chemotherapy)
Infectious agents
Bacterial infections, fungal infections, viral infections, parasitic infections
Immunologic
Our immune system can cause cell stress/injury
Autoimmune disease
Temperature extremes
too hot or too cold can damage tissue and leave someone susceptible to cell injury.
Trauma
Injured tissue can disrupt blood flow
Electrical injury
Cell membrane relies on electrochemical gradient
When someone undergoes electrical energy its disrupts cell membrane causing cell membrane to be more permeable
Allowing these ions or additional cell contents like organelles to seep out and cause cell death
Mechanisms of cell injury (how does it unfold)
ATP depletion (no O2, cant make ATP)
Mitochondrial damage (free radicals come out)
Ca2+ influx (no ATP to pump it out, activates catabolic enzymes, breaks things down and leads to cell damage)
Accumulation of reactive oxygen species (free radicals)
Damage of DNA and Protein
Increased plasma membrane permeability (including organelles)
Things can get into the cell that normally wouldnt
Things can leave the cell that normally wouldnt including organelles
Effects of hypoxic cell injury
-Cell is not getting adequate amounts of ATP
ATP depletion
Cell relies on anaerobic metabolism until glycogen stores are depleted
Without ATP you cant run the active pumps
Increase in Na+ and Ca2+ into the cell
H20 then follows = cell swells
Increased intracellular Ca2+ concentrations
Enters cell due to lack of ATP
Increased Ca2+ levels in cell activates catabolic enzymes which break things down
When catabolic enzymes break down ATP it can damage the cell membrane, nucleus, and the mitochondria
Increases its permeability so free radicals can get out and damage the cell more
Oxygen-derived free radicals = Reactive oxygen species)
destruction of cell membrane and nucleus
Defects in membrane permeability
leakage of intracellular enzymes can be in detected in the blood
Hypoxia
-Decrease oxygen delivery to cells
-Lack of O2, have to rely on anaerobic respiration
Not making as much ATP
Generates Lactic acid
Lowers pH (more acidic)
Low pH can interrupt our normal enzyme activity (
Since pH is too acidic it can damage or disrupt enzyme activity
Without enzymes working it can disrupt normal cell reactions
Lack of ATP we cant run active transport pumps
Cell starts to take in Na+ and Ca2+
Water follows (cell swells)
-If cell membrane becomes damaged and leaky the intracellular enzymes start to get into the blood
Can be used to diagnose a patient and estimate if they have a particular cell damage and how bad the damage is
Metaplasia
-Cellular Adaption
-Happens with epithelial tissue
-If cell injury gets reversed it goes back to normal
-One epithelial tissue that is normally supposed to be there undergoes some type of stress and responds to it by adapting to a new type of epithelial tissue
-The new tissue is less mature
-If new tissue keeps having to replicate we undergo a risk in that new cells DNA
More likely for mistakes if there is more turnover
-If stressor remains it could progress to dysplasia