Circulatory Disturbances (Ex2) Flashcards
What are the roles of Vascular Endothelium in hemostasis?
- anti-thrombotic and pro-fibrinolytic when normal
- pro-thrombotic and anti-fibrinolytic during injury
What are the roles of Vascular Endothelium in inflammation?
- regulates the traffic of inflammatory cells
- produces pro-inflammatory cytokines
- controls angiogenesis and tissue repair
What are the pathomechanisms of Edema?
- increased blood hydrostatic pressure
- decreased plasma colloidal osmotic pressure
- lymphatic obstruction
- increased vascular permeability
Type of fluid in Inflammatory Edema
Exudate - protein rich
Type of fluid in Non-inflammatory Edema
Transudate - protein poor
Gross appearance of Edema
- wet
- gelatinous and heavy
- swollen organs
- fluid weeps from cut surfaces
- may be yellow
Histological appearance of Edema
- clear/pale eosinophilic staining
- spaces are distended
- blood vessels may be filled with RBCs
- lymphatics are dilated
- collagen bundles separated
What is Pitting Edema?
When pressure is applied to an area of edema, a depression or dent results as excessive fluid is forced to adjacent areas
What is Anasarca?
generalized edema with profuse accumulation of fluid within the subcutaneous tissue
What are the usual causes of Pulmonary non-inflammatory and inflammatory edema?
Non: left-sided congestive heart failure
Inflam: damage to pulmonary capillary endothelium
What happens in chronic pulmonary edema?
- commonly associated with cardiac failure
- alveolar walls become thickened, may lead to fibrosis
- congestion, microhemorrhages, and accumulation of heart failure cells
What is Hyperemia?
increase of arteriole-mediated engorgement of the vascular bed
- blood is oxygenated
What is Congestion?
- passive, venous engorgement caused by decreased outflow of blood
- blood is not oxygenated
- tissues dark red to blue
What are examples of Physiological Hyperemia?
- increase blood flow to GI tract during digestion
- increase blood flow to muscles during exercise
- increase blood flow to skin to dissipate heat
- involuntary increased blood flow to the face
What is Pathological Hyperemia?
- caused by underlying pathological process, usually inflammation
- arteriolar dilatation secondary to inflammation
- reddening
What is the cause of “Nutmeg Liver”?
- subacute to chronic hepatic congestion
- low-grade hypoxia and increased pressure of hepatocytes, leading to atrophy and necrosis
What is hemorrhage by rhexis?
due to a substantial rent or tear in the vascular wall
What is hemorrhage by diapedesis?
due to a small defect in the vessel wall or RBCs passing through the vessel wall in cases of inflammation or congestion
What is hemorrhagic diathesis?
increased tendency to hemorrhage from usually insignificant injuries
What is Hemoptysis?
coughing up of blood or blood-stained sputum from the lungs or airways
What is Epistaxis?
bleeding from the nose
What are agonal hemorrhages?
petechiae and ecchymoses associated with terminal hypoxia
- results from slaughter
What is suffusive hemorrhage?
larger than ecchymosis and contiguous
What is an organizing hematoma?
a central mass of fibrin and RBCs surrounded by supportive vascular connective tissue
- will eventually be phagocytosed
Explain the resolution of hematoma (colors)
Hemoglobin (dark red/blue) is enzymatically converted to bilirubin (blue/green) and eventually into hemosiderin (gold-brown)
What are the components necessary for normal hemostasis or thrombosis to occur?
- vascular wall (endothelium)
- platelets
- coagulation cascade
Describe normal Hemostasis
- after initial injury, a brief period of arteriolar constriction occurs (augmented by endothelin)
- platelets adhere and activate
- activated platelets change shape (round to flat) and release secretory granules attracting more platelets and form hemostatic plug (primary)
- tissue factor leads to activation of coagulation cascade, culminating in thrombin
- thrombin cleaves fibrinogen to fibrin
- fibrin and platelets form permanent plug
What is a thrombus?
- aggregate of platelets, fibrin, and entrapped blood cells
- can result in occlusion of the vascular lumen ad embolism
- is adhered to the vascular wall (opposite of blood clot)
What is the pathogenesis of thrombosis?
- endothelial injury
- alterations in blood flow
- hypercoagulability (increase in coagulation factors)
What is an embolism?
What is an embolus?
Embolism: process of pieces of a thrombus breaking off the mass and lodging at distant sites
Embolus: the mass that breaks off
What is Disseminated Intravascular Coagulation?
systemic reaction in which there is generalized activation of the blood coagulation system
What is infarction?
localized area of ischemic necrosis in a tissue or organ caused by occlusion of either the arterial supply or the venus drainage
