Disorders of Circulation

Question 1

Hyperemia

Answer 1

Arteriolar dilatation and increased blood flow

Caused by sympathetic neurogenic discharge or chemical mediators (ACTIVE)

Tissues appear “redder” Ex: sites of inflammation, exercising skeletal muscle

Question 2

Congestion

Answer 2

Impaired outflow of VENOUS blood from a tissue (passive process)

Tissues have abnormal “red-blue” color

Question 3

Hemostasis

Answer 3

Series of regulated processes that;

• maintain blood in a fluid clot-free state in normal vessels
• rapidly form a localized hemostatic plug at the site of vascular injury

Question 4

Hemorrhage - Mechanisms

Answer 4

Vessel is disrupted by:

• mechanical force (trauma)
• pathologic process (congestion, inflammation, neoplastic erosion of vessel)

Question 5

Causes of Edema

Increased Hydrostatic Pressure

Answer 5

Systemic: Heart failure

Local: Impaired venous return post DVT

Question 6

Causes of Edema

Decreased colloid osmotic pressure

Answer 6

Due to reduced plasma albumin

• Decreased synthesis (liver disease, malnutrition)
• Increased loss (nephrotic syndrome: glomular apparatus malfunctioning and excessively spilling proteins into urine)

Question 7

Causes of Edema

Lymphatic obstruction

Answer 7

Neoplasm

Question 8

Causes of Edema

Increased vascular permeability

Answer 8

Inflammation

Question 9

Causes of Edema

Renal failure

Answer 9

Sodium Retention

Question 10

Pathways leading to systemic edema

Answer 10

Question 11

Thrombosis

Answer 11

Formation of blood clot (thrombus) within intact vessel

Pathologic process

Question 12

Mechanisms of Thrombosis

Answer 12

Endothelial injury: inflammation; advanced atherosclerosis

Altered blood flow: turbulence (atherosclerotic vessel narrowing) vs stasis (a.fib, bed rest)

Hypercoagulable state: presidposition to easy clot formation - inherited (protein C deficiency) and aquired (woman who smokes and uses oral contraceptives; disseminated cancer)

Question 13

Virchow’s triad in thrombosis

Answer 13

Endothelial injury

Abnormal blood flow

Hypercoagulability

Question 14

Embolism

Answer 14

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

Question 15

Types of Emboli

Answer 15

• Fragments of thrombi (thromboembolism)
• Atherosclerotic
• Amniotic fluid
• Air (gas)
• Fat

Question 16

Infarct

Answer 16

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

(pattern of necrosis will be most likely be coagulative, in brain is liquifactive)

Question 17

White infarct

Answer 17

Arterial occlusions

Solid organ with end-arterial circulation: heart, liver spleen, kidney

Question 18

Red infarct

Answer 18

Venous occlusions (ie ovarian torsion)

Tissues with dual circulations (lung, small intestine)

Loose tissues (lung)

When flow is re-established after infarction (s/p angioplasty of arterial obstruction)

Question 19

Factors that influence infarct development

Answer 19

Nature of vascular supply

Rate of development of occlusion

Vulnerability of tissue to hypoxia

Oxygen content of blood

Question 20

Shock

Answer 20

Characterized by systemic hypoperfusion of tissues with resultant;

• impaired tissue perfusion
• cellular hypoxia

Question 21

Cardiogenic shock

Answer 21

Low cardiac output due to myocardial pump failure

• MI
• Ventricular repture
• Arrhythmia
• Cardiac tamponade

Question 22

Hypovolemic shock

Answer 22

Low cardiac output due to loss of blood or plasma volume

• Hemorrhage
• Fluid loss (vomiting, diarrhea, burns, trauma)

Question 23

Septic shock

Answer 23

Arteriolar vasodilation and venous blood pooling that stems from systemic immune response to microbial infection