Circulatory pathology Flashcards
What is the basic mechanism of circulatory disorders?
What are some common examples of circulatory disorders?
Atherosclerosis -> thrombus -> ischaemia
Cardiovascular disease e.g MI
Peripheral vascular disease
Cerebrovascular disease e.g vascular dementia
Thromboembolism
How does cardiovascular disease occur?
Atherosclerosis ( formation of fatty streaks) -> narrowing of blood vessels-> thrombus/embolism -> ischaemia and lack of blood + oxygen delivery to the heart tissue
What is a pulmonary embolism?
Thrombus forms in blood vessel
Migrates to lungs -> can present as hypertension if small enough to lodge in the bronchial tree
- Can cause instant death if occurs in major pulmonary artery
Describe the pathological process of atherosclerosis
Lipid rich materials form in the tunica intima of the blood vessels
Fatty streaks deposit and thicken to become ulcerated plaques
Plaques lead to narrowing, blockage and weakening
endothelial dysfunction monocyte adhesion smooth muscle migration to intima and proliferation ECM deposition + elaboration Lipid accumulation Inflammation Plaque growth
What is Virchows triad?
3 main reasons why a thrombus may have occurred
- Endothelial damage/injury: Release of factors promoting platelet adhesion + pro coagulant factors
- Hypercoaguable state : Medications or genetic causes
- Altered blood flow e.g turbulence : Decreased delivery of anti coagulant factors ( CLOTTING INHIBITORS) + less dilution of the blood rich in clotting factors
Compare arterial + veneous thrombus
Arterial : Made of platelets + caused by endothelial injury
Veneous: Made of RBC, platelets + fibrin, caused by stasis, lower pressure + blood flow
What are the outcomes of thrombus formation?
Dissolution via fibrinolysis
Propagation: Thrombus grows
Embolism : Thrombus travels to a distant site e.g the lungs
Organisation: Blood clot becomes fibrous scar
Recanlisation: Blood vessels widen or narrows due to fibrous scar
What is the significance of dual lung circulation ?
Pulmonary artery and bronchial arteries
Reduces chance of infarction
What is infarction?
What factors determine the development of an infarct?
Ischaemic coagulative necrosis of a tissue due to an arterial or venues blockage
Vulnerability to hypoxia
Blood supply to tissues
O2 content of the blood
Compare and contrast venues and arterial blockages
Veneous blockage - red haemorrhagic ( blood cannot exit the veins) decreased veneous return
Occurs in dual circulation e.g lung, colon
Red = pale infarct, arteries become blocked
Occurs in end arterial organs e.g heart, spleen + kidney
What is dry + wet gangrene?
Dry - tissue dies and dries out with no infection
Wet - Bacterial Infection occurs -> sepsis
What is oedema?
What are the 4 main causes?
Build up of fluid in body tissues
- Increased hydrostatic pressure : Heart failure, renal failure, impaired venues return -> increased intravenous pressure
- Decreased osmotic pressure: Low plasma albumin e.g cirrhosis
- Increased vascular permeability : Inflammation,
- Impaired Lymphatic drainage : metastatic spread of the nodes, blockage, lypmphadnopathy
What is shock?
Systemic state of hypo perfusion
- low blood pressure, tissue hypoxia -> anaerobic
What are types of shock?
Anaphylactic Cardiogenic Neurogenic Hypolovaemic Septic - bacteraemia
What are the stages of shock?
Non progressive:
- Reflex compensatory mechanisms aim to stabilise vitals e.g activation of renin-angiotensin-aldosterone system to maintain perfusion to vital organs
Progressive
Irreversible:
