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109 Cards in this Set
- Front
- Back
What is the function of a lysosome? |
Cleans up waste |
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What is the function of a primary lysosome? |
House lytic enzymes – fuse with other cytoplasmic vesicles to form secondary |
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What are the three types of secondary lysosomes? |
(1)Heterophagosomes, (2)Autophagosomes, (3)Lipofuscin |
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What is the function of heterophagosomes? |
These are large vesicles that result from the fusion of phagosomes that contain ENDOCYTOSED material with lysosomes containing lytic enzymes. Thus, the digestion of material from OUTSIDE the cell takes place within heterophagosomes. |
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What is the function of autophagosomes? |
Digest cells own organelles |
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What is the function of lipofuscin? |
aka residual bodies. Remnants of digested materials from autophagosomes or heterophagosomes. Show up as age spots. |
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What is homeostatsis? |
A state of balance between opposing pressures operating in and around a cell or tissue. A state of equilibrium. |
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Describe the "steady state" in cells. |
Equilibrium between cells and their environment achieved and maintained. |
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What happens to the cell if the demand exceeds the capacity of the cell to adapt to disequilibrium? |
The cell can become damaged and cannot return to original steady state, leading to cell injury and/or death |
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What are the two types of cell injury? |
(1)Reversible, (2)Irreversible |
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Describe reversible cell injury. |
Reversible injury, cell recovery, and return to normal function |
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Define reversible cell injury. |
Adverse conditions that cause a cellular response that remains within the range of homeostasis. Injury stops--original steady state |
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*How long does reversible cell injury typically last? |
Typically mild or short-lived |
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What are three causes of reversible cell injury? |
(1)Brief hypoxia, (2)brief anoxia, (3)low concentration of toxins |
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What kind of changes can reversible cell injury lead to?
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Hydropic changes |
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How can the hydropic changes be reversed? |
Hydropic change is Reversible if toxin is removed or energy source is restored (oxygen). Cell can revert back to steady state homeostasis |
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What can anoxia or any energy deprivation cause? |
AA decreased function in Na+/K+ pump. Can’t maintain concentration gradient -- Na+ flows into cell (Cl- follows) --` increased [NaCl]INSIDE cell |
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What is the result if water can easily flow into the cell? |
Swelling |
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What are three functional changes that can occur with reversible cell injury? |
(1)Reduced energy production, (2)Decreased protein synthesis, (3)Increased autophagy |
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Why is cell energy production reduced? |
Swollen mitochondria generate less ATP |
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How does protein synthesis decrease? |
pH of cell becomes acidic (due to anaerobic glycolysis producing lactic acid) which slows metabolism and degranulation of theRER |
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How does autophagy increase? |
Damaged proteins are phagocytised and lysosome enzymes are released. A large amount of this occurring could damage other cellular components |
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Describe the two types of irreversible cell injury. |
(1)Apoptosis and programmed cell removal, (2)Cell death and necrosis |
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What are three causes of irreversible cell injury? |
(1)heavy doses of toxins, (2)anoxia, (3)prolonged hypoxia |
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What three changes in the nucleus can irreversible cell injury cause? |
(1)Pyknosis, (2)Karyorrhexis, (3)Karyolysis |
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What is pyknosis? |
condensation of chromatin |
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What is karyorrhexis? |
fragmentation of nucleus -- ‘nuclear dust’ |
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What is karyolysis? |
lysis of chromatin |
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How can irreversible cell injury affect the cell membrane? |
Causes loss of cell integrity and rupture of the cell membrane |
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Where do dead cells release their contents? |
Dead cells release their contents into extracellular fluid. Shown in laboratory blood tests – something is really wrong! |
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What are six causes of cell injury? |
(1)Hypoxia and anoxia, (2)Re-oxygenation, (3)Toxic injury, (4)Microbial Pathogens, (5)Mediators of Inflammation and Immune Reactions, (6)Genetic and Metabolic Disturbances |
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*What is the most common cause of cell injury? |
Hypoxia and Anoxia |
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What are three ways hypoxia and anoxia can occur? |
(1) Obstruction of airways, (2)decreased oxygen transportation (pneumonia, severe anemia), (3)cyanide poisoning |
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What is re-oxygenation? |
Short lived reversible cell injury due to hypoxia may be repaired by re-oxygenation |
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What is the risk of re-oxygenation? |
Oxygen toxicity. (Oxygen radicals formed ionized iron or production of hydrogen peroxide.Too much oxygen too fast may form oxygen radicals.) |
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How can re-oxygenation occur? |
Postperfusion myocardial injury |
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What are three ways a cell can experience toxic injury? |
(1)Ingestion of heavy metals, (2)Carbon tetrachloride, (3)Drugs and alcohol |
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Is ingestion of heavy metals a direct or indirect toxin? |
Direct toxin |
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What is an example of a heavy metal that could be ingested? |
Mecury |
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What is carbon tetrachloride |
commercial metal cleaning product |
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Is carbon tetrachloride a direct or indirect toxin? |
Indirect toxin |
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What happens when carbon tetrachloride is ingested? |
When ingested is metabolized into a toxic free radical |
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How can drugs and alcohol contribute to cell toxicity? |
Drug overdose |
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What are two ways that microbial pathogens can injure the cell? |
(1)Bacteria produce toxins, (2)Viruses |
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How can bacteria producing toxins injure the cell? |
Food poisoning |
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What two ways can viruses injure the cell? |
(1)Direct cytopathic effect - invade cells and kill from within, (2)Indirect cytopathic effect - integrate into cellular genome and causes the immune system to attack it’s own cell |
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What are three examples of mediators of inflammation and immune reactions? |
(1)Cytokines, (2)interferons, (3)complement proteins |
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How do mediators of inflammation and immune reactions injure the cell? |
Eliminate infectious diseases but also kill own body’s cells |
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How do genetic and metabolic disturbances? |
Many genetic diseases cause disturbances to metabolism and accumulation of toxic metabolites |
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What is an example of genetic and metabolic disturbances that injure the cell? |
Diabetes Mellitus – pathological changes to small blood vessels -- ischemia |
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What are the five types of cell adaptations? |
(1)Atrophy, (2)Hypertrophy, (3)Hyperplasia, (4)Metaplasia, (5)Dysplasia |
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What is atrophy? |
Decrease in size of a cell, tissue, organ or entire body. Can be a reduced size of a cell, reduced number of cells or both. |
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What happens to cells during aging? |
Aging and damaged organelles are eaten by autophagosomes and digested |
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What happens to undigested cell residues? |
Undigested residues form lipid-rich brown pigment called lipofuscin |
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What happens to undigested cell proteins? |
Undigested proteins are taken up by ubiquitin (scavenger protein) and marked for destruction. |
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What is physiologic atrophy? |
occurs with age and includes entire body |
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What is pathologic atrophy? |
occurs as a result of inadequate nutrition or stimulation |
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What are three examples of pathologic atrophy? |
(1)Ischemia, (2)nerve damage, (3)malnutrition |
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What is hypertrophy? |
Increase size of tissue or organs due to enlargement of individual cells. Hypertrophy alone in cardiac and skeletal muscle – cells can not divide. |
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What is hyperplasia? |
Increase in size of tissue or organs due to an increased number of cells. Increased proliferation or formation of cells. |
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What are two examples of hyperplasia? |
(1)Chronic stimulation – callus, (2)Hormones - uterus |
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What is metaplasia? |
Change of one cell type into another, but it is not normal in that area. Pre-pre-cancer. |
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What is an example of metaplasia? |
Smokers – columnar cells of the bronchial mucosa -- stratified squamous epithelium |
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Is metaplasia reversible or irreversible? |
Reversible |
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What can happen if the stimulus causing metaplasia remains? |
If stimulus remains the metaplasia may progress to dysplasia |
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What is dysplasia? |
Pre-cancer. Disorderly arrangement of cells and nuclear change. Can progress to neoplasia (Cancer). |
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What are three causes of intercellular accumulations? |
(1)A result of an overload of metabolites or exogenous material, (2)Metabolic disturbances that prevent secretion of metabolic by products and normal secretions, (3)Very complex mechanisms |
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What are the three types of intercellular accumulations? |
(1)Anthracosis, (2)Hemosiderosis, (3)Lipid accumulation |
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What is anthracosis? |
Exogenous material accumulation. Early stages of black lung. Seen in lungs of coal miners and cigarette smokers |
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What is hemosiderosis? |
Accumulation of brown pigment – hemosiderin. Derived from hemolyzed red blood cells. |
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What is an example of hemosiderosis? |
Hereditary hemochromatosis – genetic disorder of liver. Over-absorption of iron from food |
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What is lipid accumulation? |
Fatty livers due to chronic alcohol abuse or diabetes mellitus |
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What are the two reasons that cells die? |
(1)Necrosis, (2)Apoptosis |
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What are the four types of necrosis? |
(1)Coagulative, (2)Liquefactive, (3)Caseous, (4)Enzymatic fat Necrosis |
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Which type of necrosis is the most common? |
Coagulative |
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What is the cause of coagulative necrosis? |
Anoxia. Rapid inactivation of hydrolytic enzymes -- prevents lysis |
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What is the outcome of coagulative necrosis? |
Cell membrane is preserved, organelles and nucleus coagulate |
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What type of tissues does coagulative necrosis affect? |
Solid internal organs: heart, liver, kidneys |
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What the cause of liquefactive necrosis? |
Cell is completely digested by hydrolytic enzymes – ex brain infarct |
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What is the outcome of liquefactive necrosis? |
Dissolution of tissues -- soft and liquify |
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What tissues does liquefactive necrosis affect? |
Brain, skin, joints |
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What type of necrosis is a special form of coagulative necrosis? |
Caseous Necrosis |
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What is the cause of caseous necrosis? |
TB patients -- center part of tuberculous granuloma becomes necrotic and cells fall apart. Cheesy. Also found with fungal infections (histoplasmosis) |
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What organ does caseous necrosis affect? |
Lungs |
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What type of necrosis is a special form of liquefactive necrosis? |
Enzymatic Fat Necrosis |
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What is the cause of enzymatic fat necrosis? |
Lipolytic enzymes and limited to fat tissues usually around the pancreas |
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What is the outcome of enzymatic fat necrosis? |
Rupture of pancreas. Enzymes release into adjacent fat tissue degrade fat into glycerol and free fatty acids. Forms calcium soaps. |
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What are two types of necrosis complications? |
(1)Gangrene, (2)Calcification |
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Where is gangrene often seen? |
Often seen in necrotic tissue especially on extremities |
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What are the two types of gangrene? |
(1)Wet gangrene, (2)Dry gangrene |
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How is wet gangrene caused? |
Bacterial infection -- inflammation and secondary liquefaction |
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How is dry gangrene causes? |
Dried out necrotic tissue, dark black, mummified |
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What is calcification? |
Necrotic tissue attracts calcium salts. Arteries with atherosclerosis, damaged heart valves, tumours. |
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What is dystrophic calcification? |
Calcification of necrotic tissue |
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What is apoptosis? |
Active form of PROGRAMMED cell death by ‘suicide genes’ |
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Does apoptosis affect single cells or groups of cells? |
Single cells. Cell divides into apoptotic bodies -- taken up by macrophages |
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What are two types of apoptosis? |
(1)Physiologic apoptosis, (2)Pathologic apoptosis |
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What is an example of physiologic apoptosis? |
Fetal development |
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What is an example of pathologic apoptosis? |
Liver cells infected with hepatitis |
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Is the cause of necrosis exogenous or endogenous injury? |
Exogenous |
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Is the cause of apoptosis exogenous or endogenous injury? |
Exogenous or endogenous |
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What is the mechanism of necrosis? |
Vital processes are inhibited |
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What is the mechanism of apoptosis? |
Active programmed process |
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What cells are affected by necrosis? |
Multiple, organs |
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What cells are affected by apoptosis? |
Single |
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What type of cell changes are seen with necrosis? |
Swollen, ruptured, cell membrane ruptured |
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What type of cell changes are seen with apoptosis? |
Rounded up, fragmented, cell membrane in tact |
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What is the outcome of necrosis? |
Cell membrane ruptures, tissue death, bacterial infections |
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What is the outcome of apoptosis? |
Phagocytosis by macrophages |