Ischaemia and Infarction Flashcards
Define Necrosis
The spectrum of morphological changes which follows deaths of cells ad tissues, in a living organism
What are some important metabolic aberrations which commonly result from cell injury due to ischaemia?
Reduced oxidative phosphorylation Failure of sodium pump Influx of water and loss of K+ Influx of Ca+ Reduced glycogen synthesis Reduced protein synthesis
What are some of the causes of arterial occlusion?
Arterial thrombosis Embolus Vascular spasm Vascular disease with out thrombosis e.g. atherosclerosis External compression
Aside from arterial occlusion, what are two other abnormalities that may result in ischaemia?
Venous occlusion and occlusion of small blood vessels e.g. capallaries
What are some common causes of venous occlusion?
External compression and in-situ thrombosis of veins
What are some common causes of capillary occlusion?
Fat embolism, external compression, gas embolism, chronic myeloid leukaemia
What are possible outcomes of ischaemia?
No clinical or pathological effect Angina Arrhythmia Reversible cell injury Irreversible cell injury Atrophy Fibrosis Death
What are variables that influence the outcome of occlusion of vascular supply to an organ or tissue?
Architecture of blood supply, rate of development, completeness and duration of occlusion, tolerance of tissues to occlusion and systemic factors like general state of circulation
What is the first microscopic change seen of infarction following ischaemic injury?
Nuclear pyknosis
How can a blood test facilitate a diagnosis of infarction?
Raised WCC, raised ESR, or a measurement of enzyme released into the blood
What are some functional consequences of coronary artery narrowing?
Angina, cardiac arrythmia
What are the most serious consequences of cardiac aneurysm?
Heart failure
Source of thromo-embolus to other organisms
What do old cerebral infarcts look like?
Usually these appear as a cavity as a result of liquefactive necrosis, and often have surrounding gliosis (reactive change of glial cells to damage)
If a patient dies suddenly from a pulmonary lung embolus, will any changes in the lung tissue be seen/
No - morphological changes of infarction take hours to develop
Define ischaemia
The restriction in blood supply to tissues, causing a shortage of oxygen and glucose needed for cellular metabolism
