Path Flashcards
e- microscopy vs bright field microscopy vs fluorescent microscopy vs phase contrast microscope
pass e- thru specimen and look at the screen, smallest wavelength –> best resolution; can even use higher mag power; makes imgs look more “3D” vs white background d/t light source from bottom; casts a beam of light vs aka dark field microscope aka UV microscope; black background d/t no light source, you use UV light to look at fluorescent stains vs aka Nomarski interference microscope; casts light at an angle –> ring of light –> gives better contrast when looking at specimens w/ similar refractive index –> used for live or unstained specimens
relationship b/w wavelength, resolving power, and mag power
smaller wavelength –> better resolution; higher mag –> poorer resolution (like how you zoom in a photo and it looks pixelated)
all organs = composed of 2-4 basic tissues:
epithelial, connective, muscular, nervous tissues
resolving power def
capacity of lens to give separate imgs b/w objects that are very close together
how to cut super thin translucent specimens w/ paraffin and microtome (5-8 micrometers thick)
1) fixation - make cross-links w/ proteins to prevent degradation from post mortem decay –> carbs and lipids may be lost; or use formalin alc slns or rapid freezing
2) embedding - paraffin will infiltrate specimen BUT paraffin = hydrophobic so do these steps:
a) dehydration - remove water from specimen and pass specimen thru alc slns
b) clearing - pass specimen thru xylene or cedar wood oil to remove alc –> tissue = translucent
c) infiltrate specimen w/ melted paraffin –> let paraffin solidify –> specimen = embedded into paraffin
STEPS abc MAKE UP EMBEDDING
3) sectioning - cut thin sections of paraffin/specimen w/ microtome
4) mount section on slide –> remove embedding agent w/ alc –> put specimens in stains, counterstains, etc
alternative methods for making thin translucent sections (besides paraffin)
epoxy resin but harder to do and more to do; though you’ll get thinner sections (<1um thick) –> higher resolution
What are artifacts?
empty vesicles (think dentin/enamel example)
How do stains stick to specimen?
acidic stains bind w/ basic structures, basic stains bind w/ acidic structures. acidic structures = basophilic, basic structures = acidophilic
H&E vs PAS vs Mallory trichrome vs toluidine blue vs Prussian stains
hematoxylin (basic) stains nuclei –> purple, and eosin (acidic) stains cytoplasm –> pink. if not purple or pink –> mucus vs Periodic Acid Schiff; stains polysaccharides/complex carbs and proteoglycans vs stains connective tissue vs stains acidic components in shades of blue vs stains metal ions (heme/iron = most common)
immunocytochemistry
staining techniques that uses specificity of ab binding (ie: you can use labeled primary ab to stick to ag and then stain it, or use labeled secondary ab that sticks to primary unlabeled ab that sticks to ag and then stain it). ex: enzyme linked method, fluorescence method, metals for e- microscopy
What are epithelial tissues?
Derived from endo/ecto/mesoderm; line surfaces and cavities of body (skin, GI lining, hollow organs - outside vs lumen); no external matrix —> cell to cell contact —> cells = cohesive and make specialized junctions; attach to basement membrane. FOCUS ON SURFACE CELLS
What is basement membrane?
Consists of basal lamina (thin portion deep in epithelium) and reticular laminate (thick portion superficial to connective tissue; consists of reticular fibers —> need special stain to see under light microscope; secreted by connective tissue). Fibers of both lamina = intertwined —> connects epithelia to connective tissue —> provides barrier and filter exchange to underlying connective tissue
Are epithelial tissue vascular?
No, they rely on blood vessels in connective tissue
Can epithelial tissue regenerate?
Yes if not highly specialized. Most cancers = of epithelial origin (carcinomas). Adenocarcinoma = glandular epithelium tumor, papilloma = benign projecting from tumor, metaplasia = change from 1 tissue type to another
Simple squamous vs simple cuboidal & simple columnar vs pseudostratified vs stratified squamous vs stratified cuboidal/columnar vs transitional epithelia
Little cyto, 1 layer of flat cells, little to no abrasion, easily damaged b/c so thin —> can get infected from surgical procedures —> can be replaced by connective tissue (ex: endothelial lumen, lungs) vs absorption and/or secretion —> highly specialized (ex: kidney, glands), MICROVILLI vs they look stratified but each cell = actually in contact w/ basement membrane; function in secretion and have cilia (ex: URT, trachea) vs multiple layers, flattest nuclei at top (less stained), resists friction (can be keratinized to get more resistance to friction) (ex: skin, esophagus) vs extremely rare to find, usually in transition rom stratified to simple, function in secretion and/or absorption vs multiple layers, surface nuclei stay round instead of being flattened, significant expansion and reduction (ex: bladder and urinary system)
Cell adhesions: tight junctions vs gap junctions vs anchoring junctions
Aka occluding adhesion/zonula occludens, prevents material from seeping down onto b/w adjacent epithelial cells, prevents proteins from luminal surface to move to basal surface vs provide cytoplasmic passage of molec b/w adjacent cells (ions, signal transduction molec) vs link cytoskeletons of adjacent cells or link cytoskeleton to fibers of extra cellular matrix; they anchor cells together (ex: skin cells) —> resistance to shearing forces; diff types: zonula adherents, hemi/desmosomes, focal contacts; act like spot welds
Cell surface specializations: microvilli vs stereocilia vs cilia vs basal folds
Finger like projections on luminal surface, function to inc SA for max absorption, brush border/striated border appearance under light microscopy vs super long microvilli, same function as microvilli, lack microtubules that make up cilia —> poor organized motion (ex: sperm cells) vs specialized hair like projection the sweep fluid or material across epithelial surface, contain microtubules vs deep invaginations of basal surface, function to inc SA, have lots of mito in b/w folds —> basal striations
What are glands and secretory cells types: protein secreting vs mucin secreting vs steroid secreting
Organized group of epithelial cells that synthesize and secrete products; glands made up of 1+ type of secretory cell => “mixed”. Secretory cells = all either cuboidal or columnar. Aka serous glands, secrete protein, abundant in RER —>purple in H&E stain (lots of ribosomes made of protein and RNA in RER) vs aka goblet cells, mix of proteoglycans and glycoproteins that act as barriers or lubricants, stain light blue or frothy in H&E stain vs abundant in SER —> pink in H&E stain d/t cyto, lipid vacuoles don’t stain —> small clear openings in cyto
Secretary mechanism: exocrine vs endocrine
Products secreted thru apical cell membrane into a duct; merocrine - exocytosis releases material in vesicles to a duct, apocrine - material = pushed into cell surface —> cell membrane w/ bit of cyto pinches off into a vesicle, Holocrine - cell becomes distended in vesicles —> dies and is shed (ex: hair) vs products secreted thru basal cell membrane into blood vessels of underlying connective tissue
Parenchyma vs stroma of gland
Cells responsible for main function of gland/organ, often composed of epithelial cells vs supporting tissue w/in gland/organ, often composed of connective tissue
Structural types of glands: simple tubular vs simple acinar vs simple branched tubular vs cmpd tubular vs cmpd acinar vs cmpd tubuloacinar
1 branch or no branch (looks like test tube) vs cul de sac vs 2+ branches vs branch has branches vs each branch has cul de sacs vs each branch has both tubular and acinar branches and depends on where secretory portions and ducts are (sec portions reach higher)
What is connective tissue?
support, connect and/or separate other tissue types w/an an organ; all connective tissue = derived from embryonic mesenchyme/mesenchymal stem cells, small amounts remain in adults –> reappear and differentiate in wound healing; these cells also secrete and maintain variety of extracellular materials
-blast vs -cyte vs -clast
cells actively building/producing matrix vs cells actively maintaining matrix vs cells actively removing matrix
immune cells w/in connective tissues
mast cells - derived from basophils –> have abundant basophilic granules vs macrophages - derived from monocytes –> can be fixed or roaming –> become epithelioid cells when activated and clustered vs plasma cells - B cells secreting ab; have basophilic cyto and perinuclear neg Golgi imgs vs other WBCs
fibroblasts
primary and most abundant cell in connective tissues; spindle shaped but only nucleus = seen in stains –> oval shaped, finely granulated chromatin w/ 1-2 prominent nucleoli; responsible for fibers, glycoprotein and proteoglycan components of matrix
what is the matrix? what are the 2 components in matrix?
material that fills space b/w cells –> bulk of connective tissue mass. 1) ground substance - amorphous (w/o shape) material varying consistency from fluid to semisolid, sometimes solid in specialized connective tissue (ex: proteoglycans - large sugar/carb molec w/ some protein and lots of sulfate –> attracts H2O into matrix; nonfibrous glycoproteins - contain short branching carb chains attached to a protein –> mediate interaction b/w cells and extracellular matrix), and 2) fibers
what are all fibers made of? 3 types of fibers?
all = glycoproteins made and secreted by fibroblasts. collagen - fam of 27+ diff proteins made into triple helical structure to produce collagenous fibers, provide tensile strength –> bind structures together w/in body; synthesis complex (both intra/extracellular steps) vs reticular fibers (Type III collagen) - fine branching fibers forming loose mesh –> provides scaffolding to support other cells and structure of certain organs, component of reticular lamina, requires special stain w/ silver impregnation, does scars vs elastic fibers - allows tissue to recoil after stretching, can be cross linked to form sheets or filaments, requires special stain w/ aldehyde fuschin or neg img w/ H&E stain if big enough, made and secreted by smooth muscle cells
examples of specialized connective tissue?
bone, blood, cartilage
types of connective tissue proper: embryonic connective tissue vs areolar/loose irreg connective tissue vs reticular tissue vs adipose tissue vs dense irreg connective tissue vs dense reg connective tissue
mesenchyme - progenitor of all other connective tissue, mucous tissue - similar to mesenchyme except small collagen fibers = present vs packing, anchoring and/or embedding material in almost every organ of the body; contains typical components of connective tissue w/ matrix made of fluid-like ground substance w/ random collagen and elastic fibers; can replace other tissues physically after injury –> fibrosis, keloids, scleroderma vs branching network or reticular fibers that form framework of certain organs; fibers secreted by reticulocytes but other functional cells suspended w/in meshwork vs made of lipid storing cells called adipocytes embedded w/in reticular framework; the only connective tissue lacking matrix; always found in loose connective tissue except nervous system, lungs, eyelid, ears, penis, dorsum of hand; energy storage, thermal insulation and shock absorption; have 2 types: unilocular and multilocular; can be stained w/ Sudan stains or osmium tetroxide vs great abundance of large collagen fibers arranged randomly; contains few elastic an reticular fibers w/ very little matrix; forms tough fibrous sheets vs densely packed fibers running parallel to e/o
unilocular vs multilocular adipose tissue
yellow fat, lipids stored in 1 large vacuole that occupies majority of cell –> nucleus is pushed to the edge and cell has little cyto, more common in adults vs brown fat, lipids stored in small mult vacuoles –> cyto has FROTHY appearance, more common in babies, help w/ heat production since mito lacks ATPse and all energy production from Kreb’s cycle = lost as heat
def of lesion and 4 categories
structural abnmllity responsible for ill health. gross lesion - you see w/ eyes, can make dx vs microscopic lesion - looking under microscope vs ultrastructural lesion - look under e- microscope vs molecular lesion - looking at molec level (DNA, protein)
clinical manifestations: signs vs sxs
objective evidence of dz by examining physician vs subjective evidence of dz by pt
pathology classification of dz’s
congenital anomalies - occur before birth, happen in womb vs hereditary dzs - DNA abnmlities inherited from parent –> fhx vs inflamm dzs - immune system attacks own tissue (ex: graft rejection) vs degenerative dzs - tissue degenerates overtime (ex: arthritis) vs neoplastic dzs - ca, abnl growth
anatomical path and its 3 subspecialties
investigation and dx of dz from examining tissue; perform autopsies, microscopic exam of surgical biopsies, examine cytopath and hematology smear. surgical path, cytopath, forensic
surgical path vs cytopath vs forensic
study of tissue removed from living pts during surgery to dx dz, does bx’s vs studies and dx dz on cellular level, does cell collection vs does autopsies and frozen sections
def of bx. excisional bx vs incisional bx vs endoscopic bx vs punch bx vs shave bx. def of resection
removing sample tissue from body of living pt. entire mass/suspicious area (including surround skin) = removed vs portion of lesion = removed –> purely diagnostic –> have to f/u and remove the rest later prn vs endoscope = used to visually examine interior of canal or organ and remove tissue w/ forceps vs small cylindrical tube of tissue = removed, similar to incisional bx b/c you remove portion of it, seen in derm vs surgical/razor blade shaves lesion on epidermis or upper dermis, mostly seen in derm. removal of tissue en masse, often after bx confirming a dx
cell collection techniques in cytopath: spontaneous exfoliation vs mechanical exfoliation vs interventional cytology
cells shed spontaneously an collected in cytology specimen, specimen on glass slide => smear (ex: thoracentesis, paracentesis) vs cells manually scraped/brushed off surface of body (ex: pap smear) vs intervening into body to collect samples (ex: Fine Needle Aspiration - tissue sample = removed w/ thin hollow needle, US guided)
def of autopsy. clinical vs forensic (medicolegal) autopsies
examining organs of dead body. pt dies in hosp from terminal illness, dz, or age; NOT suspicious of criminal background, performed w/ permission from deceased’s relatives, identify dz/problem related to pt’s death that may have been unresolved during hosp stay vs determine cause of death and/or collect evidence that may be used in prosecution; basically find cause and manner of death (ex: cause = GSW, manner = natural, artificial, suicide, homicide, undetermined)
autopsy procedure steps
- examine docs (chart review)
- examine external body
- examine internal body (Y shaped incision, peel skin from chest wall, open rib cage and remove chest plate, remove thoracic and abd organs in 1 block => Rokitansky method, organs sampled for microscopic exam, organs = returned and body = reconstructed)
limited autopsy
autopsy exam = limited to certain areas of body, can be requested by fam; not done for criminal cases
frozen section
type of tissue processing; surgeon does procedure and wants immediate eval –> calls pathologist to take tissue and make dx in 20min
clinical path and its 5 categories
study and dx of dz from chemical change in tissues and fluids. clinical chemistry, hematopath, clinical microbio, blood banking - transfusion medicine, molecular (genetic) path
clinical chemistry vs hematopath vs clinical microbio vs blood banking - transfusion medicine vs molecular (genetic) path
measure conc of substances like sugars, lipids, proteins, ab, enzymes, hormones, electrolytes; automated vs study dz and d/o w/in blood cells and organs involved w/ hematopoiesis like peripheral blood smears, flow cytometry, immunohistochemistry vs identify organisms responsible for infection vs store and maintain blood and blood products to be transfused, type & crossmatch blood products vs isolate DNA or RNA from pts’ blood or tissue samples to dx dz and predict course of illness
main aspects of path (7)
etiology (causes), pathogenesis (mechanisms), morphology (structural change), functional change (clinical significance), clinical manifestations (s/s), clinical course - acute/subacute/chronic, complications
etiology: intrinsic/genetic factors vs extrinsic/acquired/environ factors (5)
inherited medical condition caused by DNA abnllity (ex: sickle cell anemia, CF) vs physical (burns), chemical (lead, mercury, arsenic), nutritional (deficiency, obesity, malnutrition), infectious (strep, TB), immunological (hay fever)
pathogenesis: risk factors vs primary dz
something that inc risk or susceptibility to dz vs dz w/ unknown cause; also called idiopathic, essential, or cryptogenic
O2 deprivation aka hypoxia. what happens during hypoxia?
inadequate oxygenation of tissues; most common cause of cell injury; can be generalized or localized. healthy individuals do anaerobic glycolysis –> activated 100x more rapidly, less efficient than [O] phosphorylation –> makes 2 ATP
examples of generalized hypoxia
lung-related hypoxia, hgb-related hypoxia, circulatory hypoxia, histotoxic hypoxia, tissues susceptible to hypoxia
lung-related hypoxia
ventilation effects: impaired O2 delivery to alveoli (atelectasis, pna), perfusion defects: absence of blood flow to alveoli (air going in but no O2 exchange), diffusion effects: dec O2 diffusion thru alveolar capillary membrane (ex: pulm edema, pulm interstitial fibrosis), right-to-left shunt: blood shunts from R to L side of circ (ex: tetralogy of Fallot, cyanosis)
hgb-related hypoxia
anemia: dec # in RBC and [hgb], PaO2 and SaO2 = still nml. methemoglobinemia: ferric iron instead of ferrous iron, doesn’t bind O2 –> can’t deliver O2 to tissues –> cyanosis, PaO2 = still nml but SaO2 = dec; caused by benzocaine and lidocaine (topical anesthetics) exposure. CO intoxication from housefire or suicide: CO has 250x more affinity for hgb –> carboxyhemoglobin (HbCO) –> bright red color; coma, incontinence, sz, death; CT shows globus pallidus and nucleus caudatus of basal ganglia
circulatory hypoxia
blood flow compromised –> can’t deliver O2 to tissues; caused by L heart failure from dyspnea, cyanosis, pulm edema or paroxysmal nocturnal dyspnea, or shock by persistent hypotension w/ reduced perfusion of organs and inadequate O2 in tissues;
histotoxic hypoxia
inactivation of cytochrome C oxidase (complex IV in ETC) d/t binding of cyanide –> pink skin color; causes coma w/ sz, apnea, cardiac arrest. uncoupling of oxidative phosphorylation; uncouplers prevent using chemical energy from mito e- transport to make ADP to ATP, they don’t inhibit ETC or ATP synthase; natural coupler = thermogenin in brown adipose tissue, synthetic coupler = 2,4-dinitrophenol (DNP) as insecticide
tissues susceptible to hypoxia
brain neurons die in 8min, cardiac myocytes die in 30-40min, kidney and liver epithelial cell die in 90-120min; watershed area b/w 2 blood supplies (are b/w anterior and middle cerebral arteries), subendocardial tissue, renal cortex and medulla
localized hypoxia
aka ischemia; most common cause of hypoxia; caused by arterial obstruction by thrombi or emboli –> interrupts blood flow/insufficient blood supply –> ischemic necrosis (infarct) of organ/tissue supplied by that blood vessel –> lost supply of O2, supply of substrates for metabolic and synthetic processes and removal of waste prod
reversible cell injury vs irreversible cell injury
absence of O2: loss of [O] phosphorylation –> anaerobic glycolysis = main energy source. depletion of glycogen and ATP: loss of cell fxn, accumulation of lactic acid and H+ => acidosis, Na-K pump fails, dispersion of cytoskeleton, cell swelling. These are all reversible if O2 = restored vs ischemia in myocardium: dmg to plasma membrane, mito swelling, large amorphous densities in mito matrix. calcium: loss of ATP –> no active extrusion of Ca2+ from cell, no sequestration of intracellular Ca+ in ER and mito –> rapid influx of Ca2+ in cell –> cell loses viability
necrosis vs apoptosis
lysosomes digest own cell (autolysis), and denaturation of dead cell protein –> dead tissue becomes firmer and pale 24hrs post ischemia; as cell = dying, cyto becomes hypereosinophilic (more pink), nuclear changes appear in karyopyknosis (smaller nucleus), karyorrhexis (nuclear fragments/dust), or karyolysis (dissolution of nucleus –> no longer visible) vs programmed, enzyme-mediated cell death, basically cell suicide; process = divided into 2 phases (initiation phase (to start) and execution phase (to do/die))
coagulative necrosis v liquefactive necrosis v caseous necrosis v fat necrosis v fibrinoid necrosis v gangrene
outline of dead cell = preserved, caused by ischemia –> denaturation of intracellular enzymes and structural proteins; firm in texture, cells show cytoplasmic hypereosinophilia and absent nuclei; ex: myocardium, kidney and spleen vs hydrolytic/lysosomal enzymes from necrotic cells or neutrophils dissolve cells –> dead tissue softens and liquifies; ex: abscess, infarct of brain or spinal cord, pancreatic infxn vs release of lipids from cell walls of mycobacterium tuberculosis or fungi after destruction by macs –> cheese like caseous material; yellowish-white, soft, granular like dry cheese, cells show amorphous, eosinophilic, granular focus in center of granuloma vs enzymatic fat necrosis: pancreatic enzyme lipase hydrolyzes TAG to produce free FA –> FA combine w/ Ca2+ to make soaps => saponification; grossly visible white chalky deposits in adipose, fat cells show pale outline filled w/ basophilic-staining calcified areas; trauma fat necrosis: physical injury –> dmg to adipocytes –> release of TAG and hydrolysis by lipase vs accumulation of homogenous fibrin-looking acellular material d/t dmged basement membranes in HTN or vasculitis; injured blood vessels like arterioles/venules/capillaries, cells show vessel walls really stained w/ eosin vs dry: dead tissue not removed b/c leuks can’t reach site –> dessicated –> black tissue –> pt can’t go to sepsis and die; wet: when dry gangrene = infected –> pt can go to sepsis and die
3 conditions caused by O2 deprivation
hypoxia, infarction, ischemia
5 steps to apoptosis
- cell shrink and cyto becomes dense
- chromatin becomes dense mass against nuclear membrane
- nucleus breaks up into round fragments
- cell emits protrusions that break off small round apoptotic bodies
- macs phagocytize apoptotic bodies
initiation phase of apop: extrinsic pathway vs intrinsic pathway
death receptor-mediated pathway: extracellular signals like toxins, hormones, growth factors and cytokines bind to death receptors of TNF receptor fam; ex: FAS ligand binds to FAS receptor –> trimeriztion of Fas receptor –> clustering of death domains –> FADD binds to trimerized domain –> FADD+domain binds to procaspase 8 or 10 –> become caspase 8 or 10 –> activate executioner caspases vs mito pathway: DNA dmg, free radical dmg, hypoxia, misfolding, growth factor deprivation –> trigger antiapoptic Bcl-2 proteins to dimerize and fxn, proapoptic Bcl-2 proteins to dimerize or fxn, or sensors (they promote proapoptic Bcl-2 proteins and suppress antiapoptic Bcl-2 proteins (they stop apop by binding and sequestering proapop proteins)); p53 induces apop by interacting w/ proapop Bcl-2 fam members - Bak and Bax; oligomerized Bak and Bax form a channel => mitochondrial apoptosis-induced channel –> release cytochrome C from intermembrane space to cytosol –> cytochrome C binds to Apaf-1 –> formation of apoptosome (consists of 7 Apaf-1 and 7 cyto C) –> activate procaspase 9 –> become caspase 9 –> activate executioner caspases
there are 4 BH domains Bcl-2 proteins share. name which domains for antiapop vs proapop vs sensors
BH1-4 vs BH1-3 vs BH3
what are caspases and types?
enzymes that play a role in apop; start as procaspase that later become active caspase via proteolysis prn; initiator caspases: 8, 10 for extrinsic and 9 for intrinsic; executioner caspases: 3, 6, 7
execution phase of apop
executioner caspases (primarily 3) cleaves nuclear lamin, DNA fragmentation, chromatin margination and nuclear collapse; generally these caspases target proteins for controlled proteolysis –> prevents immunostimulatory molec and minimize disruption of neighboring cells
dzs assoc w/ inhibition of apop vs exaggerate apop
ca, autoimmune dz, virus vs AIDS, neurogenerative d/o, myelodysplastic syndromes, ischemic injury, toxin-induced liver dz
TUNEL assay
Tdt-dependent UTP biotin nick end labeling: staining method that allows recognition of apoptotic nuclei in tissue sections; broken DNA ends in nucleus of apoptotic cells = visualized by horseradish peroxidase –> enzyme Tdt (terminal deoxynucleotid transferase) binds and adds biotinylated nucleotide to broken DNA –> biotin labels nucleic acid broken ends –> horseradish peroxidase binds to biotin –> visible in light microscopy
free radical def. most reactive O2 species
any species that contains single/unpaired valence e- in outermost orbital –> unstable –> highly reactive. superoxide radical (O2.), hydroxyl radical (OH.), H2O2, hypochlorous acid (HOCl); there are 2 major free radical groups: oxygen-free radicals and nitrogen-free radicals
superoxide radical (O2.) vs hydroxyl radical (OH.) vs H2O2 vs hypochlorous acid (HOCl)
when 1 e- = added to diatomic O2, primary reactive O2 species that interacts w/ secondary ROS, produced in mito, Haber-Weiss rxn: H2O2 + O2. –> O2 + OH. + OH- vs very reactive; Fenton rxn: Fe2+ + H2O2 –> Fe3+ + OH.; UV radiation splits H2O2 into OH. –> aging; ionizing radiation: gamma radiation splits H2O into OH. –> dmg protein and DNA, trigger lipid peroxidation vs involved in free radical theory of aging; peroxisomes produce H2O2 for phagocytosis (neutrophils and macs use H2O2 kill phagocytosed bacteria) vs produced by myeloperoxidase (MPO) of azurophilic granules of neutrophils to kill bacteria
biomarkers for free radical dmged tissue
8-oxoguanine: mimics thymine –> binds to adenine –> transversion mutation; OH. and peroxynitrite attacks DNA; lipid peroxidation targets cell membranes: lipid radical –> lipid peroxyl radical –> lipid hydroperoxide –> unstable and yields isoprostanes (IP), malondialdehyde (MDA) and 4-hydroxy-2-nonenal (HNE) –> cell membranes lose integrity; 3-nitrotyrosine = bio marker for peroxynitrite
peroxynitrite
nitrous oxide (NO) + O2. –> ONOO.; powerful reactive radical –> cytotoxicity; reacts w/ lipids (lipid peroxidation), DNA (fragmentation), proteins (convert to 3-nitrotyrosine, which is a biomarker for peroxynitrite –> loss of protein fxn d/t enzyme inactivation)
antioxidant defenses: superoxide dismutase (SOD) vs catalase vs glutathionine peroxidase (GPx) vs vit C (ascorbic acid) vs vit E (alpha-tocopherol)
catalyze dismutation of superoxides: O2. + O2. –> O2 + H2O2; SOD1 has Cu prosthetic group (so if you’re Cu-deficient –> dec SOD), in cyto; SOD2 has Mn, in mito; SOD3 has Zn, 3 in extracellular vs 2H2O2 –> O2 + 2H2O vs 2H2O2 + 2GSH –> 2H2O + GSSG; GPx1 removes H2O2 from mito and ER to cyto, GPx4 removes lipid peroxides; GPx contains Se in active site vs scavenges superoxide, hydroxyl radical, and peroxynitrite –> stops lipid peroxidation vs majorly stops lipid peroxidation
dzs caused by [O] stress vs ROS further tissue injury
acute radiation syndrome, carbon tetrachloride intox, acetaminophen intox, ischemia/reperfusion injury vs hereditary hemochromatosis and Wilson dz
inflamm def and 2 types
complex bio response of vascularize tissues to harmful stimuli like pathogens, dmged cells, irritants. acute inflamm - early short response by body, mainly neutrophils; chronic inflamm - occurs after delay, longer response, mainly mono/macs and lymphocytes
acute inflamm def. stimuli that triggers it. 5 signs
non specific response of vascularized tissue injury. infxn, physical trauma, chemical trauma. redness, heat, swelling, pain, loss of fxn
seq of events in acute inflamm (11)
injury –> vasodilation –> inc permeability –> exudate leakage –> margination, rolling, adhesion –> transmigration/diapedesis –> chemotaxis –> neutrophil activation –> phagocytosis –> termination of inflamm response –> resolution or scar or chronic inflamm
2 main events in acute inflamm: hemodynamic vs cellular
initial vasoconstriction: stop spread of injury, transitory & reflexive, lasts up to 30s; gradual vasodilation of arterioles and capillaries: relaxation of reflexive spasm, CAUSED BY HISTAMINE, causes bleeding to start (d/t inc blood flow); vasodilation: causes endothelial gap –> permeability changes, slowing of blood flow –> hemostasis, EXUDATE LEAKAGE (MOSTLY HIGH PROTEIN CONTENT AND CELLULAR DEBRIS); permeability changes: from inflamm chemical, occur in capillaries & small venules, junctions b/w epithelial cells loosen, fluid leak –> deliver necessary proteins to injury site and facilitate margination vs mast cells: already present in connective tissue, RELEASE HISTMINE AND HEPARIN, dmg to connective tissue leads to activation & degranulation; circulating leuks: neutrophils - arrive min post-injury, phagocytose bacteria, release chemical mediators, mono/mac - ARRIVE 24-48HRS POST INJURY, phagocytose and release chemical mediators & cytokines, remove dead tissue debris, basophils - release anti-coagulants
leuk extravasation
margination: leuks line vascular wall
rolling: mediated by L selectins and Sialyl-Lexis X on leuks binding to E and P selectins on endothelium
adhesion: tight adhesion = mediated by integrin family (LFA-1) on leuks binding to ligand ICAM-1 on endothelium
diapedesis: leuks emigrate across endothelium from circ
chemotaxis: leuks move toward chemotactic stimulus
phagocytosis def and 3 steps
cells (phagocytes = neutrophils and mono/mac) engulf and elim solid particles; degranulation and oxidative burst destroy engulfed particles. 1. recognition and attachment - opsonization (C3b, Fc fragment, IgG), 2. engulfment - phagocytic vacuole formation, 3. killing and degradation/digestion - ROS, lysozymes/lactoferrin/defensin, major basic proteins, nitric oxide
neutrophil activation
triggered by offending stimuli to: produce eicosanoids (prostaglandin, thromboxanes, leukotrienes, lipoxins), undergo degranulation (ROS, proteolytic enzymes), secrete proinflamm cytokines (chemokines, colon stimulating factor, TNF-alpha, INF, interleukins)
chemical mediators for acute inflamm (8)
from plasma or cells in response to injury/triggering stimulus; short-lived. histamine - from mast cells, causes vasodilation and inc vascular permeability; seratonin - in GI tract/mast cells/PLTs, causes vasodilation and smooth muscle contraction; bradykinins - in liver/blood; inc vascular permeability and pain (activate prostaglandins); prostaglandins - released from phospholipids for pain/fever/clotting, target of NSAIDS & steroids; complement - in liver/blood; opsonization, direct target killing, vasodilation; free radicals - released from endothelium (ex: NO2), causes vasodilation; PLT activating factor - phospholipid released from many cells, activates clotting; lysosomes - digestive enzyme breaking down ingested particles inside phagocytes
acute phase proteins
proteins involved in acute inflamm; produced primarily by liver and released in response to neutrophil and mac products like IL1, 6, 8; fxn: inc body temp and bp, dec appetite, cause somnolence (sleepiness)
ex of acute phase proteins (7)
C-reactive protein - opsonin binds to phophocholine on surface of dead cells and bacteria –> activate complement and enhance phagocytosis by mac. Haptoglobin (Hp) - binds free hgb released from RBC. Serum amyloid A (SAA) - recruit immune cells to inflamm sites; transport cholesterol to liver for secretion into bile. Fibrinogen - forms fibrin for blood clot, traps invading microbe in blood clot, cause chemotaxis. Albumin - main protein of plasma; regulates oncotic pressure of blood compartment; carriers for hydrophobic molec like free FA, lipid soluble hormones, and bile salts; saves aa for producing “pos” acute-phase proteins. Transferrin - iron-binding plasma glycoproteins controlling lvl of free Fe in biological fluid; sequesters iron complexes from bacteria depriving them of growth. Transthyretin - serum carrier of thyroid hormone thyroxine (T4); releases free T4 in plasma as anti-inflamm self defense mechanism; saves aa for producing “pos” acute-phase proteins
erythrocyte sedimentation rate (ESR)
simple, inexpensive, nonspecific lab test –> screening test NOT diagnostic. anticoagulated whole blood stands in narrow vertical tub –> erythrocytes settle out from plasma d/t gravity –> plasma at top, RBC at bottom –> measure by mL of clear plasma/1hr. fibrinogen has high affiity for RBC membrane –> RBC form stacks => Rouleaux (assoc w/ mult myeloma) –> sink faster –> sediment more rapidly; inc fibrinogen –> inc ESR
leukocytosis
neutrophilia = neutrophils inc (bacterial), lymphocytosis = lymphocytes inc (viral), monocytosis = mono inc (TB, syphillis), eosinophilia = eosinophils inc (asthma, allergies, parasites), leukopenia = dec WBCs (typhoid fever, some viral, rickettsiae, protozoa, ca, alcoholism, rampant TB)
shift to left (for acute phase indicators)
“bands” = immature neutrophils w/ band shaped nuclei (not like multi lobed nuclei found in mature neutrophils); inc bands d/t bacterial infxn –> “left shift” b/c %age of bands = reported on L side of blood chart –> bone marrow = making neutrophils at inc pace; greater shift to L –> more severe infxn; L side = immature side
cytokines. which cytokines are key players in acute inflamm? (5)
proteins produced by immune cells, support cells, endothelial cells; does autocrine, paracrine, endocrine communcation (know defs); ex: interleukins - produced by WBC to affect behavior of other WBC, interferons - produced by WBC to interfere w/ replication and spread of infectious agents, chemokines - cytokines involved in chemotaxis, growth factors - proteins stimulating cell growth. TNF and IL-1
hallmarks of acute inflamm
DILATION OF SM BLOOD VESSELS AND ACCUMULATION OF LEUKS AND FLUID IN EXTRAVASCULAR TISSUE. serous - watery (plasma), exudation of cell poor fluid in to spaces created by cell injury, ex: skin blisters (fluid accumulated under dmged epidermis); fibrinous - hemorrhagic, rich in fibrin, develops when vascular leaks = large or local procoagulant stimulus, fibrinous pericarditis (fibrin deposited in pericardium); suppurative - pus (dying neutrophils), abscess = localized collection of pus, ex: bacterial abscesses in the lung; ulcerative - dmg below basement membrane, local defect/excavation of surface of organ/tissue produced by sloughing of inflamed necrotic tissue, ex: duodenal ulcer
post acute inflamm: resolution and repair/regeneration
resolution - if little to no dmg –> inflamm resolves, return of fxn. repair and regeneration (replacement w/ same kind of tissue) - if sig dmg –> labile regeneration (fully regenerates like epithelium), stable regeneration (partially regenerates like bone), or permanent (does not regenerate like muscle)
post acute inflamm: tissue repair
forming granulation tissue (fibrous connective tissue + vessels). neovascularization - capillary budding results from mitogens, fibroplasia - mesh framework for scar development (type III collagen = laid down RANDOMLY –> not strong –> later manipulated in remodeling process to be more organized w/ type I collagen), mature scars not as strong as orig healthy tissue
clinical outcomes
complete recovery, sequelae (consequence from prev dz), recurrence, remission, death
respiratory/oxidative burst
respiratory/oxidative burst generates reactive oxygen species (i.e., superoxide anion) that are important in destruction of engulfed bacteria
top 3 leading causes of death
- heart dz
- ca
- covid in USA
