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Adaptation
Response to
Stress(physical or
chemical)
Hypertrophy
Response toDemand
(Increase ordecrease)
Metaplasia
Atrophy...
-Anacquiredformof differentiation
-Response toalteredenvironment
-Transformationof one mature cell type toanother
Metaplas...
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Disorders of Cell growth

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Disorders of Cell growth

  1. 1. Adaptation Response to Stress(physical or chemical) Hypertrophy Response toDemand (Increase ordecrease) Metaplasia Atrophy Hyperplasia Response tocell injury, acute orchronic Hypoplasia Atrophy, Hypertrophy, Hypoplasia, Dysplasia, Metaplasia&Hyperplasia. Pathological Physiological Atrophy -Decrease insize of organor cell -Organatrophymay be due to lossof cell size ornumber -Cell atrophyisdue tolossof size -Maybe mediatedbyapoptosis(programmedcell death) -Maybe Physiological (i.e.Atrophyof the uteruspostmenopause, orthymus) -Pathological maybe due todecreasedfunction,lossof innervation,reducedbloodoroxygensupply,nutritionalimpairmentor hormonal insufficiencies. Hypertrophy -Increase insize withoutcell replication. -Oftenco-existswithhyperplasia -Inpermanentcellsisthe onlyadaptive functionunderstimulatoryconditions. -Canbe physiological orpathological; -Physiological- Muscle (inc.Leftventricle) hypertrophy(i.e.Inathletes) - Uterine smoothmuscle (hyperplasiaandhypertrophy) (inpregnancyandpubertydue tooestrogens) -Pathological- Cardiac(i.e.SystemichypertensionLV,LV inaorticvalve stenosis,RV inPulmonaryvalve stenosis, RV inPulmonaryhypertension) -Arterial -Breast Cellscanalsobecome polyploid(manysetsof DNA) astheyarrestinG2 withoutundergoingmitosis.Particularlyseenincardiaccells. ExamplesincludepostMI,where asegmentof muscle dies,acompensatoryhypertrophyoccursinordertomaintaincardiacoutput. Hyperplasia -Increase incell numberbymitosis -There isalsoadecrease inthe rate of apoptosisintissue undergoinghyperplasia.The reasonwhyisunknown. -PhysiologicalCauses; -Individualslivingataltitude, bonemarrow hyperplasiaoccursinordertoproduce more red bloodcells.Stimulatedbyincrease ingrowthfactor erythropoietin. -Breasttissue atpuberty,pregnancyandlactation,influencedbyseveral growthhormones;oestrogens,progesterone, prolactin, growthhormone and humanplacental lactogen. -Thyroidhyperplasia,aconsequenceof increasedmetabolicdemands -Pathological Causes; -Intissue repair,particularlyinangiogenesis,epidermal cellsandhepatocytes. -Insome hyperplasticconditions,cellskeepproliferatingandit'shardtodefine these asseparate toneoplasms.(e.g. Psoriasis,Paget'sandfibromatoses) Hypoplasia -NOT the same as atrophy. -Whenthe organfailstoattainthe normal size or shape. -Therefore afailure inmorphogenesis. i.e.Developmentof legsof adultswithSpinabifida Metaplasia -Anacquiredformof differentiation Dysplasia Disorders of Cell Growth 14 March 2011 19:19 IMMS Page 1
  2. 2. -Anacquiredformof differentiation -Response toalteredenvironment -Transformationof one mature cell type toanother Metaplasiaisassociatedwithchroniccellularinjuryandrepairandsubsequentdevelopmentof malignancywithinmetaplastic tissue, asitisthoughtthatthe changesthat induce metaplasiamayalsoinduce dysplasia,whichif persistentmayprogresstotumourformation. i.e.StratifiedSquamousepitheliuminthe oesophagus whenexposedtochronicreflux of gastroduodenalcontents(acidandbi le),cancause metaplasiaof the lowerendof the oesophagus,causingthe squamousepitheliatochange intocolumnarglandularepitheliumasyouwouldfindinthe stomachori ntestine.(Barrett'soesophagus) Dysplasia -Abnormal Growth,characterisedbyincreasedcell proliferation(i.e.Manymitosesvisible thannormal,hyperchromasiainnuclei,decreaseddifferentiation) -Maybe causedby chronicphysical or chemical injury -Maybe reversible onlyinearlystages -Pre neoplastic -Screeningprograms(i.e.Cervical pap.Smearscreen) lookfordysplasticormetaplasticchangesinthe cellsof the cervix. IMMS Page 2

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