Cell Pathology

1. Haemodynamic disorders Describe the causes and consequences of oedema at different sites Define thrombosis and give the causes and potential consequences of such an event. Define embolism and know about the importance of pulmonary embolism in clinical practice. Describe possible causes of haemorrhage and potential outcomes Define shock and identify the possible causes and mechanisms Define infarction and describe possible causes.

Oedema Causes: Raised hydrostatic pressure Reduced plasma osmotic pressure Lymphatic obstruction Sodium retention Inflammation Consequences: Cellulitits Venous Eczema Venous Ulcer Pulmonary Cerebral

Thrombosis: Causes

Thrombosis Endothelial injury Atheromatous plaques Myocardial infarction Vasculitis Cigarette smoke Hypercholesterolaemia Abnormal blood flow Turbulence Stasis Hypercoagulability Primary (genetic) Secondary (acquired) OCP Malignancy Smoking Pregnancy Resolution Organisation Re-cannulisation Propagation Embolisation PE Coronary Deep Vein

Haemorrhage Causes Trauma Vasculitits Vascular fragility Consequences None Chronic anaemia Hypovolaemic shock Pressure

Shock Cardiovascular collapse -> hypotension, impaired tissue perfusion, cellular hypoxia Causes: Hypovolaemic: Severe haemorrhage Massive trauma Burns Sepsis Anaphylactic: hypersensitivity Cardiogenic: pump failure Myocardial infarction Massive pulmonary embolism Myocardial damage Tamponade Neurogenic: spinal trauma

Shock - Consequences Brain: ischaemic encephalopathy Heart: subendocardial ischaemia/necrosis Kidneys: acute tubular necrosis GI tract: haemorrhagic enteropathy Lungs: ARDS

2. Cell injury List the causes of cell injury List the mechanisms of cell injury Define (and give examples of) hyperplasia, hypertrophy, atrophy, metasplasia and dysplasia Describe the morphological changes associated with reversible and irreversible injury Describe the differences between apoptosis and necrosis

Reversible vs irreversible injury Fatty change Cellular swelling 1.Karyolysis- the dissolution of the nucleus - the nucleus swells and gradually loses its chromatin. 2.Pyknosis - Shrunken nucleus with condensed chromatin. 3.Karyorrhexis - rupture of the cell nucleus in which the chromatin disintegrates into formless granules that are extruded from the cell. 1.Coagulative necrosis 2.Liquefactive necrosis 3.Caseous necrosis 4.Fat Necrosis

Necrosis 1212

1 2 3 Apoptosis

The differences between apoptosis and necrosis 1.Apoptosis may be physiological 2.Apoptosis is an active energy dependent process 3.Not associated with inflammation

Bruise An extraversated collection of blood which has leaked from damaged small arteries, venules and veins but not capillaries Fragility of vessels, coagulation state etc all effect bruising May take hours or days to form May get patterned bruises (can see better with special light sources) Deep bruising may never be seen on the surface Blunt trauma

Abrasion 1 A graze or scratch The most superficial of blunt trauma injuries Confined to the epidermis (strict definition) but may actually extend into the superficial dermis due to skin anatomy) Can occur before and after death Friction burn, Whip, Stamp

Laceration 1 A split to the skin The result of blunt force overstretching the skin Usually pass through the full thickness of the skin They are deep and will bleed Margins ragged with crushing and bruising “Bridging fibres” arch across the skin defect Common where skin can be compressed between the force and underlying bone Eg Scalp, elbow, shin Rare over soft fleshy areas Eg Buttocks, breasts Fall, Punch, Kick

Cut (or slash) The length of the injury is longer than its depth

Stab (or penetrating injury) The depth of the wound is greater than the width Knife/metal

Atherosclerosis 1.Occludes arteries slowly 1.Occludes arteries slowly (angina, myocardial scarring, dementia, claudication,) 2.Occludes arteries suddenly 2.Occludes arteries suddenly plaque rupture (thrombosis, atheroembolization) or haemorrhages into plaques (MI, stroke, gangrene of the bowel) 3.Weakensartery walls 3.Weakens artery walls (aneurysms)