MOD factoids+definitions Flashcards
Define Hyperplasia
Increase in tissue/organ size due to increased cell numbers. (Only in labile/stable cells).
N.b. Response to increased functional demand or external stimulation. Reversible
Define Regeneration (cell adaptation)
Replacement of cell losses by identical cells in order to maintain the size of a tissue or organ
Define Hypertrophy
Increase in tissue/organ size due to an increase in cell size (not number).
N.b. Like plasia- response to increased functional demand/hormonal stimulation. Many tissues, but esp in permanent cell populations.
Due to more structural components
Define Atrophy
Shrinkage of tissue/organ due to acquired decrease in cell number/size
Define Metaplasia
Reversible change of one differentiated cell type to another.
N.b.Metaplastic epithelium is fully differentiated
Define Hypoplasia
Underdevelopment/incomplete development of a tissue/organ
N.b in a spectrum with aplasia. Compare to atrophy.
Define Neoplasm
An abnormal growth of cells that persists after the initial stimulus has been removed
Define malignant neoplasm
An abnormal growth of cells that persists after the initial stimulus has been removed AND invades surrounding tissue with potential to spread to distant sites
Define Dysplasia
Pre-neoplastic (May not actually ever progress to neoplasm) alteration in which cells shows disordered tissue organisation. Change is reversible
Define metastasis
Malignant neoplasm that has spread from its original site to a new non-contiguous site
Define Oncosis
Cell death w/ swelling. The spectrum of changes that occurs in living cells prior to death
Define Necrosis
The morphological changes that follow cell death in living tissue
Define Apoptosis
Cell death with shrinkage- induced by regulated energy-dependant intracellular program where a cell activates enzymes that degrade its own DNA and proteins
Coagulative necrosis
Denaturation> degradation of protein. Ghost outline of cells. Solid organs- ischaemia/infarct
MI, dry gangrene
liquefactive necrosis
Degradation>Denaturation of protein. Enzymatic digestion of tissues. Bacterial (wet gangrene), pus. Abscesses, cerebral infarct
What do you see in acute alcoholic hepatitis?
Focal hepatocyte necrosis, Mallory bodies and neutrophils
What do you see in cirrhosis?
Micronodules of regenerating hepatocytes surrounded by bands of collagen
Define Acute Inflammation
The innate, immediate and early response of living tissue to injury, initiated to localise tissue damage
Define Chronic Inflammation
Chronic response to injury with associated fibrosis
Causes of Acute Inflammation
Microbial infections, hypersensitivity reactions, physical and chemical agents, tissue necrosis
What causes Rubour and Calor?
Vasodilation of arterioles and capillaries causing an increase in blood flow. Mediated by histamine and prostaglandins
What causes Dolor?
histamine and bradykinin cause pain
What causes tumor?
Exudation of fluid into tissues caused by increased permeability of vessels. Mediated by histamine and leukotrienes
How does exudation combat injury?
Delivery of plasma proteins (Ig, fibrinogen, inflammatory mediators), increase in lymphatic drainage, dilutes toxins
How does vasodilation help?
Raises temperature locally, increases delivery
How does infiltration of cells help?
Removes pathogenic organisms and necrotic debris
Local and Systemic consequences of AI?
Local- swelling, exudate, loss of fluid, pain and loss of function
Systemic- fever, acute phase response, leukocytosis, spread of infection-> septicaemia-> shock
Sequelae of AI?
Resolution, suppuration, chronic inflammation with fibrosis, death
Describe angio-oedema
Deficiency of C1 esterase inhibitor- increased bradykinin- increased vascular permeability of endothelium- oedema
Describe chronic granulomatous disease
Defect in NADPH oxidase, can’t perform oxidative burst, can’t kill some bacteria- frustrated phagocytosis, granulomas form to contain the bacteria
Describe alpha 1 anti trypsin deficiency
Lots of trypsin cleaving proelastase to elastase in LUNGS- COPD. In LIVER- hepatitis as accumulation of antitrypsin
Sequence of lobar pneumonia
Congestion, red hepatisation, grey hepatisation, resolution.
Strep pneumoniae.
Effects of chronic inflammation?
Fibrosis (chronic cholecystitis, gastric ulceration), impaired function (inflamm bowel disease), atrophy, immune response (RA, granulomas)
Define Granuloma
Group of two or more epithelioid histiocytes with a rim of lymphocytes
What can cause granulomas?
Persistent low-grade antigenic stimulation e.g. Foreign material
Hypersensitivity (infections- TB, leprosy)
Unknown (sarcoidosis, wegeners, crohns)
Define fibrous repair
Replacement of functional tissue with scar tissue
N.b. Involves- cell migration (inflamm, endothelial, myo/fibro), angiogenesis, ECM)
Constituents of granulation tissue
Inflammatory cells, myo/fibroblasts, endothelial cells, capillaries and lymphatics, ECM proteins
Define Haemostasis
The arrest of bleeding either by physiological properties of vasoconstriction or coagulation, or by surgical means
Define Thrombosis
Inappropriate formation of a solid mass of blood within the circulatory system during life
What is Virchow’s triad?
Abnormalities of vessel wall (disturbs antithrombotic properties and nidus for platelet aggregation)
-atheroma, direct injury, hypertension, inflammation
Abnormalities of blood flow (stagnation, turbulence)
-AF, LV disjunction, venous obstruction, varicose veins
Abnormalities of blood components (hypercoaguability)
-smoking, postpartum, post-op, cancer
Define Embolism
Blockage of a blood vessel by solid, liquid or gas at a site distant to its origin
What is DIC?
Widespread activation of coagulation, generation of thrombi and subsequent Fibrinolysis- using up clotting factors and platelets.
What is thrombocytopenia?
Decreased platelets. Can be immune (antibodies against glycoproteins on platelet membranes).
Causes- decreased production (BM problems, infections, drugs, metabolic disorders), decreased survival (drugs, immune destruction, DIC), sequestration by spleen, dilutational.
What is thrombophilia?
Predisposition to thrombosis.
Caused by AT3 deficiency, protein c+s deficiency for example
Define Atheroma
Accumulation of intracellular and extracellular lipid in the intima and media of large and medium sized arteries
Define Artherosclerosis
Thickening and hardening of arterial walls due to atheroma
Define Arteriosclerosis
Thickening and hardening of artery and arteriole walls, usually due to hypertension or DM
