Disorders Circulation 8-6-15 Flashcards
What type of process is hyperemia? What happens? What is it caused by?
Active Process
-Arterial dilation and increased blood flow
-cuased by sympathetic neurogenic discharge or chemical mediators
-tissues appear “redder”
-ex:
Sites of inflammation
Exercising skeletal muscle
What is the difference and similarity between hyperemia and congestion?
Similar: increased intravascular blood volume
Difference:
Hyperemia:Active, tissues Redder
Congestion: Passive, tissues red-blue
What is congestion? What is a systemic example?
impaired outflow of venous blood from a tissue
-congestive heart failure
What does a congested liver look like macroscopically and microscopically?
Nutmeg
Blood in central vein
Hemostasis
- a series of regulated process that
- maintain blood in a fluid clot-free state in normal vessels
- rapidly form a localized hemostatic plug at the site of vascular injury
What is hemorrhage?
flow of blood from a ruptured blood vessel
What is edema?
Result of movement of fluid from vasculature into interstitial spaces or body cavities
What are 5 reasons a patient may have edema?
- Increased Hydrostatic Pressure
- systemic: heart failure
- local: impaired venous return post deep vein thrombosis - Decreased colloid osmotic pressure, due to reduced plasma albumin
- decreased synthesis(liver disease, malnutrition)
- increased loss (nephrotic syndrome) - Lymphatic obstruction
- neoplasm - Increased vascular permeability
- inflammation - Sodium Retention
- Renal Failure
transudate
low protein content, few cells
exudate
high, protein content, and may contain some white and red cells
Thrombosis
Is this pathologic?
Formation of blood clot within intact vessel
yes
What are the three key elements in thrombosis?
- vascular wall
- platelets
- coagulation cascade
What are three mechanisms of thrombosis?
- endothelial injury
- inflammation, advanced atherosclerosis - altered blood flow
- turbulence (atherosclerotic vessel narrowing) vs. stasis (atrial fibrillation, best rest) - hypercoagulable state
- predisposition to easy clot formation
- inherited: protein c deficiency
- acquired: women who smoke and use oral contraceptives; disseminated cancer
What do the three key elements in thrombosis: endothelial injury, abnormal blood flow, and hypercoagulability make up? Which is the most important factor?
Virchow’s Triad
- endothelial integrity
- abnormal procoagulants or anticoagulants can tip the balance in favor of thrombosis
- abnormal blood flow can lead to hypercoagulability directly or indirectly through endothelial dysfunction
What happens to the lumen of a blood vessel histologically when there is a thrombosis?
filled in pink when it should be white and clear
What are the fates of a venous thrombus?
- resolve
- embolization to lung
- organized and recanalized
- organization incorporated into the way
What is an embolism?
intravascular substance (solid, liquid, gas) which is carried by blood from point of origin to a distant site
What are 5 different types of emboli?
- fragments of thrombi (thromboembolism)
- atherosclerotic(calcium and cholesterol)
- amniotic fluid
- air (gas)
- fat
What is an infarct?
Area of ischemic necrosis caused by occlusion of vascular supply to affected tissue
What are majority of infarcts associated with?
-thromboembolism and involve arterial occlusions
What are the type of infarcts?
- white (pale) infarct
-arterial occlusion
-solid organ with end-arterial circulation
EX: heart, liver, spleen, kidney - red infarct
- venous occlusions-ovarian torsion
- tissue with dual circulation-lugn, small intestine
- loose tissues-lung
- when flow is reestablished after infarct-s/p angioplasty of arterial obstruction
What shape are infarcts in the lung?
- wedge shaped
- blood vessels are dead and so blood is leaving those blood vessels
What are 4 factors that influence infarct development?
- nature of vascular supply
- rate of development of occlusion
- vulnerability of tissue to hypoxia
- oxygen content of blood
What does the clinical outcome of thrombosis depend on?
- degree of occlusion of vessel lumen, collaterals, size of infarct
- partial occlusion may allow enough blood to flow to vital tissue
- complete occlusion-usually results in infarct unless there is enough collateral circulation to support oxygen requirements of the tissue
** survival of patient determined by size and location of infarct as well as collateral circulation
What is shock characterized by?
systemic hypoperfusion of tissue with resultant
- impaired tissue perfusion
- cellular hypoxia
Whis is cardiogenic shock?
-low cardiac output due to myocardial pump failure EX -MI -Ventricular Rupture -Arrhythmia -Cardiac Tamponade
What is hypovolemic shock?
-low cardiac output due to loss of blood or plasma volume
EX
-hemorrhage
-fluid loss (vomiting, diarrhea, burns, trauma)
What is septic shock?
-arteriolar vasodilation and venous blood pooling that stem from systemic immune response to microbial infection
