Pathology

Question 1

What composes the capillary wall?

Answer 1

A semipermeable barrier that influences the movement of fluids, nutrients, and waste products between the blood and interstitium

Question 2

How do lipid soluble substances, large proteins, and small polar molecules move through the capillary wall?

Answer 2

1) Lipid soluble substances -> dissolve in membrane lipid bilayer
2) Large proteins -> transport within vesicles
3) Small polar molecules -> move by inter-endothelial pores (typically passive and in response to gradients)

Question 3

How is water distribution between the plasma and interstitium determined?

Answer 3

Osmotic and hydrostatic pressure differentials

Question 4

What are the 4 causes of edema?

Answer 4

1. Increased intravascular hydrostatic pressure
2. Decreased intravascular osmotic pressure
3. Increased microvascular permeability
4. Decreased lymphatic drainage

Question 5

What can result from edema caused by increased intravascular hydrostatic pressure?

Answer 5

active increase -> hyperemia from inflammation
passive -> congestion
localized portion results in localized edema
heart failure -> generalized edema

Question 6

What are common causes of intravascular hydrostatic pressure?

Answer 6

-Portal hypertension
-Pulmonary hypertension
-Localized venous obstruction
-Fluid overload
-Hyperemia

Question 7

What can lead to edema from decreased intravascular osmotic pressure?

Answer 7

Decreased concentration of plasma proteins (albumin) leads to this. More fluid filtration and decreased absorption results
Generalized edema
Results from decreased albumin production or excessive albumin loss

Question 8

What leads to sodium and water retention?

Answer 8

When renal function is compromised -> salt is retained
Water follows salt, more salt, more water retained leading to an increase in hydrostatic pressure and decreased colloid osmotic pressure

Question 9

What cascade of events leads to increased microvascular permeability?

Answer 9

1) Initial microvascular reaction to inflammatory or immunologic stimuli
2) Localized release of mediators that cause vasodilation
3) Endothelial cells contract and widen gaps
4) Triggers release of IL-1, TNF, and interferon gamma
5) cytoskeletal rearrangement -> endothelial cell retraction

Question 10

What causes increased vascular permeability?

Answer 10

Infectious agents
Immune mediated events (type III hypersensitivity)
Neovascularization
Anaphylaxis
Toxins
Metabolic abnormalities

Question 11

What causes increased vascular permeability?

Answer 11

Infectious agents
Immune mediated events (type III hypersensitivity)
Neovascularization
Anaphylaxis
Toxins
Metabolic abnormalities

Question 12

T/F edema resulting from decreased lymphatic drainage is localized to the area served by the affected lymphatic vessel

Answer 12

True

Question 13

What can lead to decreased lymphatic drainage?

Answer 13

-Lymphatic obstruction
-Congenital lymphatic aplasia
-Intestinal lymphangiectasia
-Lymphangitis

Question 14

What is the difference between Hyperemia and Congestion?

Answer 14

Hyperemia results from a greater arrival of blood to a tissue (increased inflow)
Congestion results from blood accumulating in a tissue due to an obstacle preventing its exit (decreased outflow)

Question 15

What are the two types of hyperemia?

Answer 15

1. Physiologic hyperemia
   -tissue with increased metabolic activity
   -stimulation of nerve centers that stimulate pressure
2. Pathologic hyperemia
   -inflammatory process, caused by vasodilator substances released from affected tissues

Question 16

What are the subsets of congestion?

Answer 16

1) Local congestion -> acute local and chronic local
2) Generalized congestion -> acute generalized and chronic generalized

Question 17

What causes acute local congestion?

Answer 17

compression of veins in a portion of the body that is often the result of poor viscera position (intussusception, volvulus, etc.)

Question 18

What causes chronic local congestion?

Answer 18

Results from gradual or partial obstruction of venous circulation in an area, allowing tissue to adapt to the lower blood supply
Caused by external pressure or obstruction inside the vein

Leads to cellular atrophy and proliferation of connective tissue

Question 19

What causes acute generalized congestion?

Answer 19

Sudden obstruction of blood flow in the heart or lungs

Cardiac causes: degeneration and necrosis of myocardium (myocardial infarcts, hydro, hemoperricardium, suppurative pericarditis)

Pulmonary causes: pneumonia, embolism, thrombosis, hydrothorax, hemothorax, empyema

Question 20

What causes chronic generalized congestion?

Answer 20

Results from chronic obstruction of blood flow in the heart or lungs, causing permanent alterations in various tissues and organs

Cardiac: Valvular stenosis and insufficiency, myocardial failure, cardiac anomalies, constrictive lesions of epi and pericardium

Pulmonary: Obliteration of capillaries, chronic alveolar emphysema, pneumonia, hydrothorax, hemothorax, empyema, compression of major pulmonary vessels

Question 21

What results from right cardiac insufficiency?

Answer 21

Blood accumulates in great veins and liver
Subcutaneous fluid accumulates in ventral areas, extremities, and body cavities
Liver with increased reticular pattern (nutmeg liver)

Question 22

What results from left cardiac insufficiency?

Answer 22

Accumulation of blood and increased hydrostatic pressure in the lung
Extravasated erythrocytes in alveoli and phagocytized by macrophages (cardiac failure cells)

Question 23

What is cor pulmonale?

Answer 23

an alteration in the structure and function of the right ventricle of the heart caused by a primary disorder of the respiratory system. Pulmonary hypertension is often the link between lung dysfunction and the heart in cor pulmonale

Question 24

What is hypostatic congestion?

Answer 24

pooling of blood in the ventral areas of the body due to gravity

Question 25

What can cause hemorrhage to occur?

Answer 25

Abnormal function or integrity of the major factors that influence hemostasis -> endothelium, blood vessels, platelets, coag factors
Significant and minor vascular injury

Question 26

What are common causes of petechiae?

Answer 26

Result from diapedesis due to minimal vascular damage, low platelet counts, and defective platelet function

Question 27

What are the generalized and local effects of hemorrhage?

Answer 27

Generalized: acute and chronic anemia, hypovolemic shock

Localized: mechanical damage from organ compression, severity depends on affected organ

Question 28

What is a thrombus and what is it formed by?

Answer 28

Thrombus is a pathologic formation of a blood clot formed by platelets, fibrin, and leukocytes