#5 disorders of circulation

Question 1

Hyperemia

Answer 1

occurs due to dilation of an artery or arteriole and increased blood flow into the capillaries. Caused by sympathetic neurogenic discharge or chemical mediators. examples- acute inflammation, blushing, body’s need to dissipate heat. the skin appears red (oxygenated blood)

Question 2

congestion

Answer 2

passive hyperemia. occurs due to impaired venous drainage, lack of blood flow. Can be systemic or isolated. examples- congestive heart failure, poor venous drainages (blue/red deoxygenated blood)

Question 3

edema

Answer 3

accumulation of abnormal amounts of fluid in interstitial spaces or body cavities

Question 4

non-inflammatory edema

Answer 4

fluid accumulates due to changes in hydrostatic pressure and colloid osmotic pressure. Transudate

Question 5

inflammatory edema

Answer 5

tissue injury alters blood flow and vascular permeability as a result of increased inter-endothelial space. modulated by chemical mediators. Exudate

Question 6

hemostasis

Answer 6

maintains blood as a liquid and prevents uncontrolled bleeding

Question 7

hematoma

Answer 7

hemorrhage that is contained within a tissue

Question 8

hemathorax

Answer 8

bleeding into the space between the chest wall and the lung (the pleural cavity)

Question 9

hemopericardium

Answer 9

bleeding into the pericardial sac of the heart

Question 10

hemoperitoneum

Answer 10

bleeding into the peritoneal cavity. The blood accumulates in the space between the inner lining of the abdominal wall and the internal abdominal organs.

Question 11

hemarthrosis

Answer 11

bleeding into joint spaces

Question 12

petechiae

Answer 12

a small red or purple spot caused by bleeding into the skin, mucous membranes or serosal surfaces. Caused by low platelet counts, defective platelet function and low of vascular wall support (vit C deficiency)

Question 13

purpura

Answer 13

slightly larger than petechiae, result from the same things as petechiae plus trauma, vascular inflammation, and increased vascular fragility

Question 14

ecchymosis

Answer 14

larger than purpura (1-2 cm) subcutaneous hematomas (bruises). Extravasated red cells are phagocytosed and degraded by macrophages. Color changes due to enzymatic conversion of hemoglobin to bilirubin and hemosiderin.

Question 15

thrombosis

Answer 15

formation of a blood clot within an uninterrupted vascular system- always pathologic

Question 16

3 mechanisms for thombrosis

Answer 16

1. endothelial injury (inflammation, advanced atherosclerosis)
2. Altered blood flow (turbulence vs. stasis) (atrial fibrillation, bed rest)
3. hypercoagulable state (protein C deficiency, women on BC and smoking)

Question 17

embolism

Answer 17

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

Question 18

types of embolisms

Answer 18

Fragments of thrombi (thromboembolism)
Atherosclerotic
Amniotic fluid
Air (gas) (can occur during surgery or decompression sickness)
Fat (during trauma fat from bone marrow enters circulation)

Question 19

Infarction

Answer 19

and area of ischemic necrosis within a tissue or an organ. produced by occlusion of either its arterial supply or venous drainage. usually associated with thromboembolism and involved arterial occlusion.

Question 20

types of infarct

Answer 20

1. white: ischemic usually arterial occlusion

2. red (hemorrhagic), usually venous occlusion

Question 21

what determines the outcome of a thrombus

Answer 21

1. degree of occlusion
2. size and location of the blood vessel
3. collateral circulation

Question 22

shock

Answer 22

systematic hypo perfusion of tissue. Caused by either diminished CO or reduced effective circulating blood volume

Question 23

3 most common types of shock

Answer 23

1. cardiogenic - low CO due to myocardial pump failure
2. hypovolemic- low CO due to loss of blood or plasma volume
3. septic shock - arteriolar vasodilation and venous blood pooling from a systemic immune response to microbial infection

Question 24

Causes of edema

Answer 24

1. Increased hydrostatic pressure (Systemic: Heart failure
   Local: impaired venous return post deep venous thrombosis)
2. Decrease 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)

Question 25

Virchow’s triad in thrombosis

Answer 25

Balance between endothelial integrity, abnormal blood flow and hypercoaguablity.
Endothelial integrity is the most important factor.
Abnormalities of procoagulants or anticoagulants can tip the balance in favor of
thrombosis. Abnormal blood flow (stasis or turbulence) can lead to hypercoagulability
directly and also indirectly through endothelial dysfunction.

Question 26

Fate of a Venous Thrombus

Answer 26

1. resolution
2. embolism to lung
3. organized and recanalized (restores some blood flow, may be incorporated into the wall)
4. propagation toward the heart

Question 27

White (pale) infarct

Answer 27

Solid organ with end-arterial circulation

Heart, liver, spleen, kidney

Question 28

Red infarct

Answer 28

Venous occlusions (Ovarian torsion)
Tissues with dual circulations  (Lung, small intestine)
Loose tissues (Lung)
When flow re-established after infarction (S/p angioplasty of arterial obstruction)