Unit 1 Flashcards
What is atrophy?
Decreased cell size
What is hypertrophy
Increase in the mass of a cell
What is hyperplasia?
Increase in the number of cells
What is dysplasia?
Abnormal cell growth
What is metaplasia?
Adaptive substitution to a different “hardier” cell line
How do cells become injured?
Hypoxia, free radicals, lead poisoning, toxic chemical agents, ethanol, trauma, asphyxia, nutritional imbalances, extreme temperature, atmospheric pressure, water pressure, ionizing radiation, noise, and cellular accumulations
What is hypoxia?
Deprivation of oxygen and is the most common cause of non-adaptive cellular injury
What causes hypoxia?
Low levels of oxygen, poor or absent hemoglobin, respiratory or cardiovascular disease, or ischemia
What occurs due to hypoxia?
There is a reduction of oxidative metabolism so ATP levels decline, change in membrane permeability, cellular accumulations, decrease in protein synthesis, increase in glycolysis.
What happens when ATP levels decline?
Na/K pump activity decreases; Na accumulates inside the cells and water follows. Intracellular K decreases
What happens due to excess Na and water inside the cell and a decrease in K inside the cell?
Decreased protein synthesis, decreased membrane transport (symport and anti port systems are disrupted), and increased lipids (lipogenesis)
What is a result of cell damage/ cell death?
Water accumulation
What is a result of change in membrane permeability?
There is an increase in intracellular Ca++ that impairs mitochondrial function
What is cellular accumulation?
Abnormal amount of substances in the cell; increase in water, increase in lipids, increase in proteins
Why does hypoxia cause a decrease in protein synthesis?
Ribosomes are separated from endoplasmic reticulum due to increase levels of fluid
Why does hypoxia cause an increase in glycolysis?
Glycolysis does not require oxygen; where electron transport chain does
What is a result of an increase in glycolysis?
Lactic acid accumulates and causes low cellular pH; lysosomes swell and dump, chromatin clumps, proteins denature
What is a free radical?
An atom or molecule with an unpaired electron, which makes it very unstable and active
Give 3 examples of free radicals
Superoxide ion (O2-), Hydroxyl (OH-), and Peroxinitrite ion (ONOO-)
What causes the formation of free radicals?
Normal metabolism, ionizing radiation, and drug metabolism
What are the 3 types of mechanisms to cause injury due to free radicals?
Lipid peroxidation, Protein destruction, and DNA alteration
What is lipid peroxidation?
Destruction of unsaturated fatty acids
What is protein destruction?
Fragmentation of polypeptide chains and denaturation
What is DNA alteration?
Breakage of DNA strands
How do you inactivate free radicals?
Antioxidants and enzymes
How do antioxidants inactivate free radicals?
Block synthesis
Name 5 antioxidants
Vitamin E, vitamin C, albumin, ceruloplasmin (carries copper), and transferrin (carries iron)
How does lead poisoning cause cellular injury?
Interferes with neurotransmitters in the CNS resulting in wrist, finger and foot paralysis in the PNS. Interferes with hemoglobin synthesis; acts like iron by binding to hemoglobin decreases oxygen carrying capacity
Name 6 sources of lead poisoning
Paint, dust and soil, contaminated tap water, dyes, and pottery glazes
Give an example of toxic chemical agents that cause cellular injury
Carbon monoxide (CO); has 300x the affinity for hemoglobin as oxygen does
What are some symptoms of CO poisoning?
Nausea and vomiting, headache, weakness, and tinnitus (ringing in the ears)
How does ethanol cause cellular injury?
In the liver ethanol is covered to acetaldehyde which is toxic to the liver due the formation of free radicals
What are the 3 most common forms of cell injury?
Hypoxia, reactive oxygen species and free radicals, and chemical injury
Define blunt-force injury
Mechanical injuries resulting in tearing, shearing, or crushing of tissues
What is a contusion?
Bleeding into the skin or underlying tissue; a bruise
What is a hematoma?
A collection of blood in an enclosed space; compartment syndrome
What is an abrasion?
Removal of the superficial layers of the skin
What is laceration?
A rip or tear when the elasticity of the skin or tissue will not hold up to the pressure applied by injuring object
What is an incised wound?
A cut that is longer than it is deep
What is a stab wound?
A cut that is deeper than it is long
How does a stab wound compare to a puncture wound?
A puncture wound is smaller
What are the 2 types of gunshot wounds?
Penetrating = bullet remains in the body and perforating = bullet exits the body
What is asphyxia?
Failure of airflow (oxygen) to the lungs
Name 4 types of asphyxia
Suffocation = blocking the airway (choking), strangulation = outward compression, chemical = impair cells ability to pick up oxygen, and drowning = anything where fluid is involved
How do nutritional imbalances cause cellular injury?
Low levels of plasma proteins (albumin) encourages water to move into the tissues causing edema, hyperglycemia and hypoglycemia, and vitamin deficiencies
Name 5 physical agents that cause cell injury
Extremem temperatures, atmospheric pressure, water pressure, ionizing radiation, and noise
What is hypothermia?
When the body core temp is less than 35 degrees C
What are some results of hypothermia?
Vasoconstriction and ice crystal formation causing cellular swelling
What happens to the blood viscosity as a result of hypothermia?
It increases; blood gets thicker
What is hyperthermia?
When the body core temp is greater than 40.6 degrees C
What is a result of hyperthermia?
Loss of fluids and plasma proteins; sweat a lot
How does atmospheric pressure cause cell injury?
Blast injuries in which compressed waves of air squeeze you; thorax collapses, organs hemorrhage and rupture
How does water pressure cause cellular injury?
Causes nitrogen to dissolve in blood then when pressure is removed, nitrogen is released and forms gas emboli (air bubbles)
Explain how ionizing radiation causes cellular injury?
When radiated electrons are removed from active cells creating free radicals
What is the most vulnerable target for radiation and when?
DNA when cells are actively replicating - pregnancy and sperm cells
How is cellular injury caused by noise?
Acute loud noise or cumulative effect; hair cells in the cochlea are damaged and decreasing hearing ability
Cellular accumulations
Water, lipids, carbohydrates, glycogen, protein, pigments, calcium, and urate
Define necrosis
Local cell death involving self/auto digestion and lysis
What the 5 types of necrosis?
Coagulative, liquefactive, caseous, fat, and gangrenous
Coagulative necrosis
Caused by protein denaturation; albumin is changed from a gelatinous transparent state to a firm, opaque state
What plays a role in coagulative necrosis?
Intracellular calcium
Where is coagulative necrosis commonly found?
Kidneys, hear, and adrenal glands
Liquefactive necrosis
Brain cells have a large amount of digestive enzymes (hydrolase) that cause neural tissue to become soft and liquefy
Can liquefactive necrosis occur due to infections?
Yes; hydrolytic enzymes are released from neutrophils to fight invading pathogens
Where is liquefactive necrosis commonly found?
Occurs in neurons and glial cells of the CNS (brain)
Caseous necrosis
Combination of coagulative and liquefactive necrosis; the tissue is destroyed but not completely digested resulting in remaining tissue looking like clumped cheese
What causes caseous necrosis?
Pulmonary infections with Mycobacterium tuberculosis (TB)
Where is caseous necrosis most common?
The lungs
Fat necrosis
Lipases found in very high levels in “lipo” (fat) tissues; break down triglycerides, releasing free fatty acids which combine with calcium, magnesium, and sodium to form soaps
Where in fat necrosis commonly found?
Breast, pancreas, and abdominal tissues
Gangrenous necrosis
Wide-spread death of tissues due to hypoxia
Name the 3 types of gangrenous necrosis
Wet (liquefactive), dry (coagulative), and gas (bubbles of gas form)
What causes gas gangrenous necrosis?
Clostridium bacteria (anaerobic) also found in tetanus and botulism cause gas bubbles to form
What is apoptosis?
Cell death involved in normal and pathological conditions that depends on cellular signals to signal protein cleavage (proteases) within the cell
Apoptosis vs Necrosis
Apoptosis is an active process, affects scattered, individual cells, and results in cell shrinkage, not lysis and swelling
Suicide victim
Apoptosis
Gene activation in “chosen” cells
Apoptosis
Cells shrink
Apoptosis
Homicide victim
Necrosis
Death is widespread
Necrosis
Cells swell and lyse
Necrosis
Aging and cell death is caused by
Accumulations of injurious events (environment) and is the result of genetically-controlled developmental program
Mechanisms of aging include
Genetic, environmental, and behavioral, changes in regulatory mechanisms, and degenerative alterations
What is somatic death?
Death of an entire organism; cessation or respiration and circulation
Name the 4 signs of somatic death
Algor mortis, livor mortis, rigor mortis, and postmortem autolysis
What is algor mortis?
Skin becomes pale and the body temperature decreases
What is liver mortis?
Blood collects and the skin changes to a purplish color on the peripheral tissues
What is rigor mortis?
Depletion of ATP keeps contractile proteins from detaching causing muscle stiffness (myosin remains permanently bound to actin); usually diminishes within 12 - 14 hours
What is postmortem autolysis?
Break down of muscle and other tissues
What is the distribution of body fluids?
40% solids and 60% liquid (water)
What is the percentage of intracellular fluid?
2/3
What is the percentage of extracellular fluid?
1/3
What components are in ECF?
Plasma, lymph, synovial fluid, interstitial fluid, CSF, urine, sweat, intestinal, biliary, hepatic, and pancreatic
What are the 3 osmotic forces?
Isosmotic, hyperosmotic, and hyposmotic
Define isosmotic
Concentrations of two fluids separated by a membrane are equal
Define hyperosmotic
The concentration of the ECF is higher than that of the ICF. Net movement is from ICF to ECF
Define hyposmotic
The concentration of the ICF is higher than that of the ECF. Net movement is from ECF to ICF
