Disorders Circulation 8-6-15 Flashcards Preview

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Flashcards in Disorders Circulation 8-6-15 Deck (28):
1

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

2

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

3

What is congestion? What is a systemic example?

impaired outflow of venous blood from a tissue

-congestive heart failure

4

What does a congested liver look like macroscopically and microscopically?

Nutmeg
Blood in central vein

5

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

6

What is hemorrhage?

flow of blood from a ruptured blood vessel

7

What is edema?

Result of movement of fluid from vasculature into interstitial spaces or body cavities

8

What are 5 reasons a patient may have edema?

1. Increased Hydrostatic Pressure
-systemic: heart failure
-local: impaired venous return post deep vein thrombosis

2. Decreased colloid osmotic pressure, due to reduced plasma albumin
-decreased synthesis(liver disease, malnutrition)
-increased loss (nephrotic syndrome)

3. Lymphatic obstruction
-neoplasm

4. Increased vascular permeability
-inflammation

5. Sodium Retention
-Renal Failure

9

transudate

low protein content, few cells

10

exudate

high, protein content, and may contain some white and red cells

11

Thrombosis
Is this pathologic?

Formation of blood clot within intact vessel
yes

12

What are the three key elements in thrombosis?

-vascular wall
-platelets
-coagulation cascade

13

What are three mechanisms of thrombosis?

1. endothelial injury
-inflammation, advanced atherosclerosis
2. altered blood flow
-turbulence (atherosclerotic vessel narrowing) vs. stasis (atrial fibrillation, best rest)
3. hypercoagulable state
-predisposition to easy clot formation
-inherited: protein c deficiency
-acquired: women who smoke and use oral contraceptives; disseminated cancer

14

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

15

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

16

What are the fates of a venous thrombus?

1. resolve
2. embolization to lung
3. organized and recanalized
-organization incorporated into the way

17

What is an embolism?

intravascular substance (solid, liquid, gas) which is carried by blood from point of origin to a distant site

18

What are 5 different types of emboli?

1. fragments of thrombi (thromboembolism)
2. atherosclerotic(calcium and cholesterol)
3. amniotic fluid
4. air (gas)
5. fat

19

What is an infarct?

Area of ischemic necrosis caused by occlusion of vascular supply to affected tissue

20

What are majority of infarcts associated with?

-thromboembolism and involve arterial occlusions

21

What are the type of infarcts?

1. white (pale) infarct
-arterial occlusion
-solid organ with end-arterial circulation
EX: heart, liver, spleen, kidney

2. 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

22

What shape are infarcts in the lung?

-wedge shaped
-blood vessels are dead and so blood is leaving those blood vessels

23

What are 4 factors that influence infarct development?

1. nature of vascular supply
2. rate of development of occlusion
3. vulnerability of tissue to hypoxia
4. oxygen content of blood

24

What does the clinical outcome of thrombosis depend on?

1. 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

25

What is shock characterized by?

systemic hypoperfusion of tissue with resultant
-impaired tissue perfusion
-cellular hypoxia

26

Whis is cardiogenic shock?

-low cardiac output due to myocardial pump failure
EX
-MI
-Ventricular Rupture
-Arrhythmia
-Cardiac Tamponade

27

What is hypovolemic shock?

-low cardiac output due to loss of blood or plasma volume
EX
-hemorrhage
-fluid loss (vomiting, diarrhea, burns, trauma)

28

What is septic shock?

-arteriolar vasodilation and venous blood pooling that stem from systemic immune response to microbial infection