Disorders of Circulation

Question 1

hyperemia

Answer 1

• active proces involving arteriolar dilation and increased blood flow which is caused by sympathetic neurogenic discharge or chemical mediators
• tissue appears redder
• ex. sites of inflammation or exercising skeletal muscle

Question 2

congestion

Answer 2

• passive process caused by impaired outflow of venous blood from a tissue
• systemic process vs isolated process
• acute vs chronic
• tissues have abnormal red-blue color
• ex. congestive heart failure causes hepatic congestion

Question 3

chronic hepatocyte congestion leads to…

Answer 3

-ischemia (blood squeezes hepatocytes) and centrilobular hepatocyte necrosis

Question 4

hemostasis

Answer 4

series of regulated processes that maintain blood in a fluid clot-free state in normal vessels and that rapidly form a localized hemostatic plug at the site of vascular injury

Question 5

hemorrhage

Answer 5

• flow of blood from a ruptured blood vessel into a tissue, body cavity or outside the body
• if a fragile vessel is congested, it can rupture and hemorrhage

Question 6

hemorrhage mechanisms

Answer 6

• bleeding occurs when large or small blood vessels are disrupted by a mechanical force or a pathological process like congestion, inflammation, or neoplastic erosion of vessels
• abnormal hemostasis can cause a predisposition to bleeding
• always abnormal except for menstrual cycle

Question 7

edema

Answer 7

-result of movement of fluid from vasculature into the interstitial spaces or body cavities

Question 8

function of lymphatics in edema

Answer 8

-absorb excess fluid until they reach their mac volume

Question 9

equilibrium of fluid in body by ____ and ___

Answer 9

hydrostatic pressure and oncotic pressure

Question 10

Causes of edema

Answer 10

• incr hydrostatic pressure (ex. heart failure or impaired venous return post deep venous thrombosis)
• decr colloid osmotic P due to reduced plasma albumin (from decr synthesis - liver disease or malnutrition- or incr loss - nephrotic syndrome)
• lymphatic obstruction (ex. neoplasm)
• incr vascular permeability (inflammation)
• sodium retention (renal failure)

Question 11

kwashiorkor and edema

Answer 11

severe malnutrition causes hypoproteinemia causing full body edema

Question 12

how does heart failure cause edema by affecting the kidneys?

Answer 12

-decr renal blood flow activates the renin-aldosterone-angiotensis system causing you to retain salt and water

Question 13

thrombosis

Answer 13

• formation of blood clot (thrombus) within intact vessel

- always pathological

Question 14

three key elements keeping balance between hemorrhage and thrombosis

Answer 14

• vascular wall
• platelets
• coagulation cascade

Question 15

mechanisms of thrombosis

Answer 15

• endothelial injury (ex. inflammation, advanced atherosclerosis)
• altered blood flow (ex. turbulence from atherosclerosis or stasis from atrial fibrillation (scar tissue in heart isn’t contractile so blood can pool there) or bed rest)
• hypercoagulable state (ex. protein C deficiency or women who smoke and use oral contraceptives)

Question 16

Virchow’s triad in thrombosis

Answer 16

1. Endothelial injuyry - most important factor which can also cause abnormal blood flow or hypercoagulability
2. Abnormal blood flow - can affect endothelial injury and hypercoagulabilty
3. Hypercoagulability

Question 17

fate of a venous thrombus

Answer 17

• resolution by a firinolytic system that can breakdown the thrombus
• embolism to the lungs
• organization and incorporation into a wall
• organized and recanalized (restore flow)
• propagation towards the heart

Question 18

embolism

Answer 18

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

Question 19

types of emboli

Answer 19

• fragments of thrombi
• atherosclerotic
• amniotic fluid
• air
• fat- severe trauma to bone can cause some of the intra-marrow fat to go into circulation

Question 20

infarct

Answer 20

• area of ischemic necrosis caused by occlusion of vascular supply to the affected tissue
• majority of infarcts are associated with thromboemobolism and involve arterial occlusions

Question 21

white (pale) infarct

Answer 21

• arterial occlusions

- solid organ with end-arterial circulation like heart, liver, spleen, and kidney

Question 22

red infarct

Answer 22

• venous occlusions- ovarian torsion
• tissues with dual circulation - lung, small intestine
• loose tissues- lung
• when flow is re-established after infarction- ex. angioplasty of arterial obstruction
• red because of associated bleeding

Question 23

factors that influence infarct development

Answer 23

• nature of vascular supply
• rate of development of occlusion
• vulnerability of tissue to hypoxia
• oxygen content of the blood

Question 24

clinical outcomes of thrombosis

Answer 24

• depends on degree of occlusion of vessel lumen, collaterals, and 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

Question 25

shock

Answer 25

systemic hypoperfusion of tissues causing cellular hypoxia

Question 26

cardiogenic shock

Answer 26

• low caridac output due to myocardial pump failure

- ex. MI, ventricular rupture, arrhythmia, and cardiac tamponade (=pericardial effusion)

Question 27

hypovolemic shock

Answer 27

• low cardiac output due to loss of blood or plasma volume

- ex. hemorrhage or fluid loss (vomiting, diarrhea, burns, trauma)

Question 28

septic shock

Answer 28

-arteriolar vasodialtion and venous blood pooling that stems from systemic immune response to microbial infection