module 1 Adaption, Inflammation, & Healing Flashcards
what is pathophysiology?
the study of functional changes in cells, tissues and organs altered by disease or injry
what is an acute illness
part of the innate (non-specific) immune response to tissue injury or microbial infection. Relatively severe, but short term
what is a chronic illness?
lasts longer than acute inflammation.Your body continues sending inflammatory cells even when there is no outside danger
how can cells be altered?
- adaptation
- injury: reversible or irreversible
- death: necrosis or apoptosis
- aging
- neoplasia
what are the 5 types fo cell adaptation?
- atrophy
- hypertrophy
- hyperplasia
- metaplasia
- dysplasia
what is cell atrophy?
a decrease in size
what is cell hypertrophy?
increase in size
what is hyperplasia?
increase in the number of cells
what is metaplasia?
reversible replacement of one mature cell type by another, sometimes less differentiated, cell type
what is dysplasia?
abnormal changes in size, shape, and organization of mature cells
what is a cell injury?
when the cell can no longer maintain homeostasis or cannot adapt
what are the 4 causes of cell injury?
- physical agents
- chemical
- biological microorganisms
- nutritional deficiences
what are 3 mechanisms/forms of cell injury?
- hypoxia
- impaired calcium homeostasis
- free radicals
what is hypoxia?
lack of sufficient oxygen for cells
- the most common cause of cell injury
what causes hypoxia?
- ischemia
- arteriosclerosis (narrowing of arteries)
- embolisms (sudden acute anoxia)
- decreased oxygen in the air
- loss of hemoglobin/RBC
- diseases of respiratory/cardiovascular systems
- poisons/toxins
what is ischemia?
reduced blood supple to cells in one area
what is arteriosclerosis?
gradual narrowing of arteries
what are embolisms?
sudden acute anoxia (something stuck in blood vessel)
Describe how loss of pump activity can lead to cellular swelling, cellular damage, and necrosis.
- Na+/K+ pumps slow down due to the lack of ATP = no maintenance of Na+/K+ input/output
- potassium will move out of the cell, sodium will move into the cell, drawing in water = swelling of the cell
- endoplasmic reticulum (ER) will then start to swell and fragment mitochondria function = further reduction of ATP
- lack of ATP results in an increased intracellular level of Calcium in the cell, leading to increased permeability and loss of mitochondrial membrane potential
Without adequate oxygen, cells are unable to produce sufficient levels of which critical energy-rich macromolecule? How does this affect cellular pH?
- decreases amount of ATP = increased anaerobic respiration
- increased anaerobic respiration = lactic acid buildup
- lactic acid buildup = lower pH
- lower pH = DNA clumping & decreased activity of many enzymes
Describe the mechanism whereby hypoxia leads to changes in cell membrane permeability
- decreased amount of ATP = phospholipid synthesis reduced
- phospholipid synthesis = less membranes and damaged membranes
- lysosomal membrane damage = leakage of degradative enzymes that degrades macromolecoles = necrosis
- mitochondiral membrane damage = change in membrane permeability = necrosis
- plasma membrane damage = influx of fluids & ions = loss of cellular contents = necrosis
explain impaired calcium homeostasis
- activation of innapropriate enzymes causing
- breakdown membrane
- nuclear damage- breakdown nuclear & damaged DNA structure
- decreased ATP
- increased mitochondiral permeability causes:
- reduction in mitichondrial membrane = decrease ATP production
- leakage of proteins from inside of mitochondria into the cytosol = apoptosis
what are free radicals?
chemical species with an unpaired outer electron that makes chemicals really unstable & highly reactive
what are reactive oxygen species (ROS)?
- mostly endogenous products (ex: metabolic processes, WBC)
what are commonly produced ROS?
- superoxide
- hydrogen peroxide
- hydroxy radical
how are ROS kept in check?
ROS scavengers
- enzymes reacts with the free radical and neutralize them
- antioxidants
how are free radicals produced?
can be exogenous (from environment) or endogenous (our own chemical reactions
- produced by phagocytic leukocytes to use them to kill pathogens
- generated by absorption of radiation from X-rays or UV light
- generated during the metabolism of many drugs
explain the process of apoptosis
- destruction of nucleus = release of DNA fragments into intracellular environment = DNA chopped up
- cell is going to dhrink from its neighbours and remove itself easily
- blebs start to form on membrane
- blebs pinch off and enclose components of intracellular environments as apoptotic bodies
- apoptotic bodies cleaned away from phagocytes
what is the purpose of apoptosis?
- so old cells can be replaced with new cells
- remove those cells during normal development
- cell is infected, don’t want to cause additional harm
how does apoptosis and necrosis differ?
- apoptosis only happens on cells that been activated for the apothotic pathway
- no inflammation is involved since everything is contains in apoptotic bodies that the phagocytes remove easily
- necrosis is messy
what is necrosis?
unregulated cell death = messy
what is apoptosis?
programmed cell death caused by both normal and pathologic tissue changes (cell suicide)
explain the process of necrosis
- interference of tissue regeneration/healing of the area = distinctive changes in tissue appearance due to messyness
- cell swells/bursts causing leakage of enzymes into the environment and self-digestion = autolysis
- there is damage to nearby tissues due to the leakage into environment and self-digestion
- during autolysis, enzymes start to degrade the cell itself because of leakage of digestive enzymes and damage to nearby cells = inflammatory response
what are the different types of necrosis?
- coagulative necrosis
- liquefactive necrosis
- caseous necrosis
- fat necrosis
Describe the causes, locations and appearance of the following types of necrosis: coagulative
- cause: hypoxia and characteristics of infarcts (lack of blood flow to area), manifesting of protein denaturation
- location: kidneys, heart, and adrenal glands
- appearance: tissue firm and opaque (clear, white-ish colour)
Describe the causes, locations and appearance of the following types of necrosis: liquefactive
- cause: tissues soften and liquefy in abscess: cells completely digested
- location: focal bacterial or fungal infections, and brain
- appearance: an abscess (pus-filled pocket)
Describe the causes, locations and appearance of the following types of necrosis: caseous
- cause: a combination of coagulative and liquefactive necrosis
- location: lungs due to tuberculosis infections
- appearance: tissue is “cheese-like”, crumble yellowish appearance
Describe the causes, locations and appearance of the following types of necrosis: fat
- cause: leakage of pancreatic lipases into peritoneal cavity causing “saponification”
- location: breast, or anywhere with fatty tissue
- appearance: tissue appears opaque and white
what is gangrene?
- results from severe hypoxic injury
- significant tissue area whose cells have undergone necrosis
what are the different types of gangrene?
- dry grangrene
- wet grangrene
- gas gangrene
Describe the causes, locations and appearance of the following types of gangrene: dry
- cause: coagulative necrosis
- location: in extremities
- appearance: skin becomes dry, wrinkles, and dark
Describe the causes, locations and appearance of the following types of gangrene: wet
- cause: liquefactive gangrene
- location: internal organs, can easily spread to other tissues
- appearance: cold, swollen, and black with foul odour due to bacterial action
Describe the causes, locations and appearance of the following types of gangrene: gas
- cause: infection with a species of bacteria (clostridium)
- location: connective tissue
- appearance: bubbles of gas formation
Outline two main categories of theory for the aging process
- programmed (moelcular) theories
- damage (senescence) theories
what are the inflammatory cells involved with acute inflammation?
- endothelial cells
- platelets
- neutrophil
- macrophages
- mast cells
- basophils
- eosinphil
what are the key chemical mediators for acute inflammation?
- histamine
- prostaglandine & leukotrienes
- nitric oxide & reactive oxygen species
- cytokines
- chemokines
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describe the sequence of cellular-chemical interactions that produce the cellular response
- leukocytes (neutrophils/monocytes/macrophages) come in contact with inflammatory chemicals in the blood stream at site of injury
- margination: leukocytes move to edge of blood vessels and accumulate at the endothelium to get ready to move to damaged tissue
- adhesion: leukocytes stick to endothelial cells by adhesion molecules, to stick to the edge so they can start to move through blood vessels
- transmigration: leukocytes move out of blood vessel, into tissue, to site of injury
- chemotaxis: chemical signals recuit the leukocytes to exactly where they need to be to deal with infection
- leukocytes migrate over and phagocytose (ingest) foreign material
describe the sequence of cellular-chemical interaction that produce the vascular response
- damaged tissue cells release cytokines (signals) and chomokines into intertistitial fluid to bring WBC to the area and get in contact with othr cells in the immune system
- mast cells become activated. by cytokines, bacterial PAMPs, other antigens, physical stress
- mast cells release histamine (key mediation in getting infammatory response happening) = vasodilation of blood vessels and increase permeability of capillaries
- fluid and blood proteins leak into interstitial fluid of tissues = edema (swelling)
- edema and vasodilation = heat, swelling, redness, loss of function, pain brought on by bradykinin