Flashcards in PP Deck (158)
Are pale cells or pink cells alive or dead?
Pale cells are alive, pink cells are dead (have taken up eosin stain)
Name free radicals and how they cause damage
Damage cell membranes by stealing electrons from neighbours
How do anti-oxidants work
vits ACE donate an electron
Name three things that can happen to a nucleus in necrosis
Pyknosis- nucleus shrinks and dark
Karyorrhexis- breaks into bits
Karyolysis- nucleus dissolves
Describe features of a dying cell
Swollen, chromatin clumps, blebs, ER and mito swell, ribosomes detach
Difference between oncosis and necrosis
Oncosis is process of dying, necrosis is changes after death 12-24hours
4 types of necrosis
Coagulative (e.g. heart, kidney), liquefactive (brain), caseous (TB), fat (breast)
Describe how to prepare slides
Add formalin to prevent auto lysis, put in casettes, processor adds water and paraffin wax, blocking, microtome cuts 3-4microns thick, float on warm water bath to remove creases, stain, mount on medium
Explain dystrophic and metastatic calcification
Dystrophic- localised calcium crystals from dying/damaged tissue e.g. athero plaques, TB LNs. Crunchy. Normal Ca metabolism
Metastatic- systemic abnormal Ca metabolism e.g. increased breakdown of bone from excess PTH or destruction of bone e.g. Paget's disease of bone, immobilisation
What is mallory's hyaline?
Keratin clumps in alcholic liver disease
What do HSPs do?
Fix misfolded proteins e.g. ubiquitin
Apoptosis definition and process
programmed cell death with shrinkage, membrane integrity maintained. p53 activated and outer membrane becomes leaky, cytochrome C released from mito which activates caspases (or TNFa from Tc binds to death R to activate caspases), apoptotic bodies made which express surface proteins, no inflam
Define gangrene (and dry, wet, gas)
Gangrene is visible necrosis. Dry is exposed to air, wet is infection, gas is infection with anaerobes (soil e.g. motorbike accident)
What are red and white infarcts?
White: in solid organs with occluded end artery
Red: in loose tissues with collateral circulation, or if re-perfused or haemorrhage
What's ischaemia-reperfusion injury?
Reperfusion can make it worse as brings ROS, brings neuts (inflam and damage), and increases complement
Give examples of when K, enzymes, and myoglobin are released from damaged cells
K in MI, AST and ALT in liver damage, myoglobin in rhabdomyolysis
Stem cells show ____ replication and are __potent
Asymmetrical replication (one stays a stem cell) and unipotent
Describe process of repair/resolution
Healing by secondary intention
Granulation tissue (new capillaries from endo cell prolif, fibroblasts make ECM and myofibroblasts contract)
Early scar (can't lay down elastin, no melanocyte regen)
Compare healing by primary and secondary intention
Primary is incised, non-infected wound with minimal tissue loss, low granulation tissue, v minimal scar. Basal epidermal cells creep and deposit BM to undermine scab
Secondary is excisional, large tissue loss, or infected, lots of granulation tissue, leaves scar, takes longer, needs big contraction
Components of granulation tissue?
Fibroblasts, myofibroblasts, endothelial cells (angiogenesis), macrophages
What cell connecting molecules are there?
Cell:cell is cadherin, cell:ECM is integrins
What are the principles of haemostasis?
Vasoconstriction, platelet plug blocks, blood coag and fibrin clot (makes clot stable), fibrinolysis
stopping bleeding whilst maintaining fluidity of blood
What normally inhibits coagulation in blood
Endothelial prostacyclin and NO inhibit platelet aggregation
Plus nothing for platelets to bind to: vWF not expressed
How do platelets work?
Block the hole- have cytoskeleton proteins to change shape, have pseudopodia to help sealing. Release granules. Have a fibrin R to cross-link with other platelets
What granules do platelets have?
Dense: adrenaline, ATP, ADP, calcium, 5HT
Alpha: fibrinogen, thromboxane A2 (vasoconstricts and platelet aggregation)
Describe the fibrinolytic system
Plasminogen ---TPA---> plasmin which breaks down fibrin. Protein C (protein S is a cofactor) decreases fibrin formation, antithrombin III and TFPI
What are PT and APTT?
PT is extrinsic, APTT intrinsic + common
What do D-dimers measure
Released from fibrin of clot as it hardens