Pathology Week 2 Flashcards
What percentage water is the body? Where is the water?
60%. 40% of the 60% is intracellular, 15% interstitial, 5% intravascular
Osmolality
Concentration of particles in a solution
Osmolarity
Osmolality in the blood
Normal plasma osmolality
280mosm/L
What is driving force
Osmolality difference
What has equal osmolarity?
intravascular, interstitial, and intracellular spaces
What has equal concentration of small solutes?
The extracellular spaces - interstitial and intravascular
How are water soluble substances transported?
via solvent drag
What is oncotic pressure
A type of osmotic pressure created by proteins
What two pressures are involved in filtration (movement out of capillary)?
Capillary hydrostatic pressure and interstitial oncotic pressure
What two pressures are involved in absorption (movement in)?
Capillary oncotic pressure and interstitial hydrostatic pressure
Starling’s Equation?
Jv=Kf(filtration-absorption) where Jv is fluid movement, Kf is hydraulic conductance
Normal net fluid movement
Out at beginning of capillary, in at end.
Where does excess filtered fluid go?
Returned to circulation by lymphatics
Hypoalbuminemia
Oncotic pressure of capillary too low, more filtered out than reabsorbed. Comes from severe protein malnutrition and leads to Kwashiorkor
Congestive heart failure
Elevated hydrostatic pressure. Right sided failure leads to peripheral edema, left sided leads to pulmonary edema.
Sepsis and inflammation
From increased hydraulic conductance. Capillary leak syndrome in meningitis.
Lymphatic impairment
Can be surgical or mechanical, leads to lymphedema (eg post mastectomy
What is edema?
Too much interstitial fluid.
What is anasarca?
Generalized edema
What are effusions?
Excess fluid in body cavities, considered edema (eg hydrothorax/pleural effusion)
What is a transudate?
Type of edema. Accumulations of salt water with very low protein content and low specific gravity. Occurs when hydrostatic pressure pushes water and salt out of normal vessels and exceeds the ability of lymphatics to drain. Due to increased intravascular hydrostatic pressure, decreased intravascular osmotic pressure, increased sodium retention from renal dysfunction, and lymphatic obstruction. Pitting edema.
What is an exudate?
Protein rich accumulations of salt water. Occurs when vessels are permeable and leak protein. Seen with inflammation. Occurs in anaphylaxis.
Hemostasis
Arrest of hemorrhage. Blood coagulation, platelet coagulation, endothelial cell interactions
Thrombus
coagulated blood containing platelets, fibrin, and entrapped cells
Extrinsic clotting pathway
Plasma contacts Tissue Factor (imp for de novo coagulation)>Factor VII>Factor X>Prothrombin>Thrombin>Fibrinogen>Fibrin. Clotting also triggers fibrinolysis, which determines size of thrombus.
Intrinsic clotting pathway
More important in lab analysis, involves Hageman factor
Role of platelets in thrombosis
primary hemostatic plug. Von Willebrand factor binds platelets to underlying collagen. Aggregation activated by thromboxane A and ADP. Prostacyclin and nitric oxide inhibit platelet aggregation.
Virchow’s Triad (causes of thrombosis)
Endothelial injury, alteration in flow, hypercoagulable blood.
Examples of endothelial injury
Endothelial injury can come from athersclerotic plaques, inflamed cardiac valves (endocarditis), inflamed vessels (vasculitis), MI, latrogenic (caused by medical treatment - e.g. catheters), hypertension, turbulent blood flow.
Examples of altered blood flow
Atrial fibrillation (left atrium stops contracting, wiggles), aneurysms, atherosclerotic plaques, dilated cardiac ventricles, and obstruction (imp. in venous thrombi due to stasis which predisposes to thrombosis).
Hypercoagulable blood
Primary is inherited, secondary is acquired. Primary includes Factor V Leiden, prothrombin gene mutation, Protein C or S deficiency, Antrithrombin III deficiency and homocystinuria. Secondary are pregnancy and OCPS, cancer, antiphospholipids, polycythemia (too many RBCs)
Lines of Zahn
Alternating layers of fibrin/platelets and RBCs indicative of thrombus formation in flowing blood
Clot
Blood solidified outside of vascular system or postmortem. Not attached to wall or vessel. Separates into two components. No lines of Zahn.
Things thrombi can do
Propagate, lyse, organize and recanalize, become infected, embolize
Embolus
Anything other than liquid blood that can travel through and lodge somewhere.
Thromboemboli
Most common are pulmonary emboli. DVTs often source. Sudden death. Pulmonary hemorrhage.
Arterial emboli
Occlude organs. Sources are heart and atherosclerotic vessels
Paradoxical embolus
Thrombus in venous or right sided circulation that sends embolus into systemic circulation. Must shunt through heart - through atria via patent foramen oval (20-25% of people don’t have full closure). Ex: DVT of lower extremity that leads to embolic infarct of brain.
Atheroemboli
Debris from ruptured atherosclerotic plaques. Cholesterol crystals in blood vessels.
Air embolism
The bends! Can happen in delivery, chest trauma, cardiac surgery.
Fat embolism
After fractures, ortho surgery.
Infarction
Irreversible tissue necrosis due to ischemia in discrete area. Coagulative necrosis (hypereosinophilia and absence of nuclei)
Ischemia
An imbalance of oxygen supply and demand due to loss of blood flow from obstructed arterial flow or reduced venous drainage
White infarcts
Obstruction of arterial supply and single blood source and not reperfused and solid tissue.
Red infarcts
venous insufficiency or dual blood supply or reperfused and loose tissue
Disseminated Intravascular Coagulation (DIC)
Excessive secondary coagulation (from TF release of endothelial damage) from thrombi in the microvasculature - micro infarctions. Depletes clotting factors and platelets, and bleeding diathesis ensues to lack of hemostasis - shock from hemorrhage. You see schistocytes (fragmented RBCs in blood smear)
Shock definition and causes
circulatory collapse - global hypotension with hypo perfusion of tissues. 3 causes: hypovolemia (hemorrhage), cardiogenic (MI, arrhythmia), sepsis (microbial infection).
Shock pathophysiology
Lactic acidosis from anaerobic respiration. Hypotension. Tissue ischemia and necrosis. Multisystem organ failure.
Septic Shock
Secondary to infection, due to capillary leak syndrome. Vasodilation and vascular permeability. Frequently leads to DIC.
Stages of shock
Nonprogressive/compensated: blood pressure maintained, no urine output, tachycardia, peripheral vasoconstriction, recovery possible. Progressive/uncompensated: renal failure, BP down which leads to lactic acidosis. Irreversible: BP and pH down, organs die, death.
Pathology of shock
Necrosis of areas furthest from arterial supply and necrosis of vulnerable cells - neuronal cells and tubular kidney cells
Hypertrophy
Increase in size of cell due to increased # organelles. Can be caused by high blood pressure (myocardial hypertrophy), unilateral nephrectomy, pregnancy (myometrial hypertrophy).
Hyperplasia
Increase in number of cells. Can occur in nursing glandular breast tissue, chronic blood loss (erythroid hyperplasia),
Atrophy
Decrease in size and function of cell. Can also decrease number of cells. Menopause, aging, immobilization, starvation. Cells initiate autophagy for breakdown of organelles
Metaplasia
Replacement of one differentiated tissue with another differentiated tissue (reprogramming of stem cells).
Intracellular storage problems
Triglycerides in alcoholic liver, hemosiderin (breakdown product of Hgb) in hemochromatosis, sphingomyelin in Niemann Pick, precursor tyrosine metabolites in hereditary tyrosinemia, mucopolysaccharides in Hurler syndrome, partially folded precursor proteins in Alpha 1 antitrypsin deficiency (leads to liver scarring from entrapment of alpha 1 and pulmonary emphysema due to lack of alpha 1), carbon dust - pulmonary fibrosis or coal workers pneumoconiosis
Hydropic Changes in Cells
influx of sodium and water into damaged cell, reversible
Reversible vs. Irreversible cell injury
Swelling of organelles, disaggregation of ribosomes, cytoplasmic blebs all reversible, calcium deposits within mito, disrupted plasma membrane, fragmentation of organelles all irreversible
Dystrophic calcification
Occurs within injured tissues, normal serum calcium and normal calcium metabolism. Ex: heart valves, atherosclerotic blood vessels, areas of necrosis, neoplasms. Used for breast CA dx.
Metastatic calcification
Occurs within normal tissues, increased serum calcium levels, derangement of calcium metabolism (hyperparathyroidism, destruction of bone, Vit. D tox, chronic renal failure)
Coagulative necrosis
common sequela of ischemic injury. Denaturation, cells lose nuclei but retain original structure
Pyknosis
Irreversible condensation of chromatin in nucs
Karyorrhexis
Fragmentation of nucs
Karyolysis
Loss of nucs
Liquefactive necrosis
Common sequela of bacterial or fungal infection. Forms abscess (localized collection of pus), breakdown of underlying tissue