like altitude, wetness, radiation, lightning, fire
Define Nutritional Deficiency
nutrients not available
due to medical intervention
mental or emotional connection
Name Intrinsic Etiologic Factors
Name Inanimate Extrinisic Etiological Factors
Physical Agent Induced:
Name Animate Extrinisic Etiologic Factors
Poor Perfusion or intterrupted blood flow
Describe what happens during Hypoxic Injury
Lack of oxygen --> ATP deficit --> decrease in ion pump activity --> Na and water accumulate in the cytosol and in organelles --> anaerobic respiration --> acidification --> enzyme dysfunction due to abnormal pH
Describe what happens during Reperfusion Injury
Ca 2+ ions suddenly become available --> enter cells and activate destructive enzymes that target lipids --> cell contents spill --> local immune cells activated --> Chemokines are released from immune cells --> Neutrophils arrive and release reactive oxygen species --> Inflammation
Define Nutritional Injury
Lack of essential vitamins and minerals prevents cell funcion and cell division
Define Infectious Injury
Bacterial enzymes damage host connective tissue and plasma membranes --> bacterial exotoxins interfere with host neuromuscular signals --> Bacterial endotoxins cause inflammation
Define Immunologic Injury
the immune system is activated by chemicals that are associated with injured host cells and/or infective agents
What is the Etiology of Chemical Injury
free radicals that damage
antimetabolites interfere with DNA synthesis
conversion to toxic compounds
What are Physical and Mechanical Injury
extreme atmospheric pressure
Mechanical deformation --> cell membrane tear, ischemia, blunt force
Electric Current --> disrupts neuromuscular signaling, causes burns, causes blood clots
What are the effects of electromagnetic radiation?
acute cell destruction
How does electromagnetic radiation damage cells
damage is caused by breaking chemical bonds and by generating free radicals
What is Hydropic Swelling?
Decreased ATP stalls Na+/K+ pumps --> Na+ accumulates inside cell
What are the characteristics of Hydorpic Swelling?
Swelling of cells
Large, pale cytoplasm
What is Intracellular Accumulations?
excess accumulation of normal stuff (e.g. fat, carbs, glycogen, proteins)
excess accumulation of abnormal stuff
excess accumulation of pigments/particles the cell normally would degrade
What is Atrophy?
Cells become smaller and less active
What causes atrophy?
Lack of nutrients or oxygen
Lack of hormonal stimuli
Injury due to inflammation or infection
What is Hypertrophy?
may be more active or develop abnormal activities
What is Hyperplasia?
cells divide more often so more cells then normal are present
What are some examples of Hyperplasia?
Liver cells in the presence of toxins
Blood vessel endothelial cells in artherosclerosis
What is Metaplasia?
One normal cell type change to another cell type
e.g. ciliated columnar changes to stratified squamous in smoker's bronchi
What is Dysplasia?
Normal cells go abnormal but are not yet malignant
Abnormal variations in cell shape, size, and arrangement
What are the two types of irreversible cell injury?
Necrosis and Apoptosis
What is the cause of Necrosis
Ischemia or toxic injury
What happens during Necrosis?
cell rupture, contents spill into extracellular space, inflammation
What happens during Apoptosis?
cell commits suicide
cell in ingested by neighboring cells
What happens during Necrosis?
high intracellular Ca+2 levels cause activation of destructive enzymes --> internal structures destroyed --> cell contents fine way into bloodstream --> inflammation, malaise, fever, increased heart rate, WBC increased, loss of appetite
What are the four types of Necrosis at the tissue level?
What causes Coagulative Necrosis?
deals with denatured proteins and is solid
What causes Liquefactive Necrosis?
inschemia in the brain tissue or a bacterial infection in any tissue with WBC involved
causes cyst or abscess
What causes Caseous necrosis?
mycobacterial infection or tumors
debris gets walled off by WBCs
What causes Fat Necrosis?
due to injury to fat or pancreatitis
causes fatty acid calcium soaps to form
What are the three types of Gangrene?
Wet, dry, and gas
What is Dry Gangrene?
large area of coagulative necrosis
blackened, dry, wrinkled tissue that has clear separation from healthy tissue
What is Wet Gangrene?
coagulative or liquefactive necrosis followed by infection
spreads rapidly, releases toxins into bloodstream --> very life threatening
What is Gas Gangrene?
wet gangrene has been infected with Clostridium perferingens, an anaerobid bacteria
infections spreads fast thru necrotic tissue
What is the difference between Necrosis and Apoptosis?
Apoptosis is programmed cell death, no cell contents are spilled, no inflammatory response occurs
Necrosis involves spillage of cell contents into interstitial space, causes inflammatory response, is alway abnormal
What causes Apoptosis?
-loss of survival signals from adjacent cells
-delivery of Fas Ligand to activate "death" receptors on plasma membrane
-DNA damage with accumulation of protein p53
-Intracellular Enzymes and signals
What are the steps of Apoptosis?
Activation of caspase enzymes
Breakdown of cellular structures
Apoptic bodies released
Phagocytosis of apoptotic bodies
What are the theories of Aging?
Somatic Mutation Theory
Programmed Senesence Theory
What is the somatic mutation theory?
DNA damaged by background radiation causes aging
What is the Free Radical Theory?
Cumulative free radical damage causes aging
What is the Immunologic Theory?
Autoimmune responses cause aging
What is the Error-Prone Theory?
Random errors in protein translation causes aging
What is the Neuroendocrine Theory?
The decline in hormone levels and hormone-receptor sensitivity causes aging
What is the programmed Senescence Theory/
Cells undergo a finite number of divisions and then die
The telomeres shorten over time
What are the events of Somatic Death?
Pallor, dilated pupils, body temperature falls, fluids collect in dependent areas
6 hours later --> rigor mortis
What is rigor mortis?
accumulation of calcium and depletion of ATP --> prolonged crossbridge formation (can't release muscle contraction)
What is Brain Death?
Absence of reflexes
Absence of respiratory effort
Absence of brain waves
Lack of cerebral blood flow
What are Pathophysiologic processes?
challenges that disrupt normal cell function
How do cells respond to challenges?
Cell Injury --> Cell Death
Notes for first lecture on Cell Injury, Aging, and Death