Organ Failure

Question 1

define lymphatics

Answer 1

blind ended capsillaries that dump into venous system

Question 2

what maintains the flow of lymphatics?

Answer 2

muscle contractions since it is low pressure and valved

Question 3

how much of the body weight is fluid? what is this fluid comprised of?

Answer 3

60% = intracellular 40% + extracellular 20% (plasma 4% + interstitium 16%)

Question 4

which circulation is this?

Answer 4

lymphatic vessel

Question 5

which circulation is this?

Answer 5

arteriole/venule
gaps in endothelium allow movement of fluid

Question 6

what forces interstitial fluid into lower pressure venules and lymphatics?

Answer 6

hydrostatic pressure

Question 7

here for Liz Brain

Question 8

list the main controls of fluid movement

Answer 8

hormones - RAAS, ANP (cardiomyocytes)
receptors - osmoreceptors, baroreceptors
osmotic/hydrostatic forces
integrity of vascular system

Question 9

what does RAAS do that controls fluid movement?

Answer 9

vasoconstriction and water retention

Question 10

what does atrial natriuretic peptide (ANP) do that controls fluid movement?

Answer 10

promotes renal sodium and water excretion and stimulates vasodilation

Question 11

define shock

Answer 11

cardiovascular collapse - systemic hypoperfusion due to macro/micro-circulatory failures

Question 12

describe the outcome of shock (pathogenesis)

Answer 12

hypotension > impaired tissue perfusion > cellular hypoxia > anaerobic metabolism > cellular degeneration > cell death

Question 13

describe the progression of shock to an irreversible state in terms of metabolism

Answer 13

hypovolemic shock > initial compensation > progression, metabolism shift to glycolysis > progressive morphological deterioration of cells

Question 14

list the types of shock via macrocirculatory failure and define each

Answer 14

1. cardiogenic - failure of heart to properly pump blood
2. hypovolemic - reduced circulation of blood volume by massive blood/fluid loss

Question 15

list examples of cardiogenic macrocirculatory failure

Answer 15

myocardial infarction
ventricular tachycardia
HCM
DCM
cardiac output obstruction (pulmonary embolism, aortic stenosis)
pericardial tamponade

Question 16

ID pathology - what type of shock?

Answer 16

cardiogenic shock - macrocirculatory failure in horse

expanded pericardial sac, cardiac tamponade

Question 17

define cardiac tamponade

Answer 17

compression of heart caused by fluid collecting in sac surrounding the heart
*example of cariogenic shock > macrocirculatory failure

Question 18

ID pathology

Answer 18

aortic rupture and cardiac tamponade

Question 19

ID pathology

Answer 19

hemangiosarcoma at R auricle and cardiac tamponade

Question 20

list the types of shock due to microcirculatory failure

Answer 20

blood maldistribution
1. anaphylactic shock
2. septic shock
3. neurogenic shock

Question 21

Describe how blood is maldistributed in microcirculatory failure?

Answer 21

decreased peripheral vascular resistance and polling of blood in peripheral tissue

Question 22

what type of hypersensitivity of anaphylactic shock?

Answer 22

type I (IgE) hypersensitivity

Question 23

what mainly causes septic shock?

Answer 23

endotoxemia from gram negative bacilli

Question 24

what causes neurogenic shock?

Answer 24

trauma, spinal cord injury, electrocution, fear, emotional stress

Question 25

anaphylactic shock pathogenesis

Answer 25

exposure of insect/plant/drug/vaccine > IgE mediated mast cell degranulation > histamine/mediators > systemic vasodilate and increased vascular permeability > blood hypotension > tissue hypoperfusion

Question 26

septic shock (most common) pathogenesis

Answer 26

Toxin (ex. LPS from gram negative bacterial cell walls) > LPS forms a complex with blood proteins > LPS bind to TLR-4 > down-regulation of anticoagulants (tissue factor pathway inhibitor and thrombomodulin) and increasing production of IL-1, IL-6, TNF (monocytes/macrophages)

Question 27

list the major antithrombotic systems

Answer 27

1. protein c - protein s thrombomodulin system 2. antithrombin III 3. tissue factor pathway inhibitor

Question 28

LPS intoxication is ___ dependent

Answer 28

dose

Question 29

Describe the pathogenesis of high production of TNF, IL-1, IL-6/8, NO, and PAF leading to septic shock?

Answer 29

High production of TNF, IL-1, IL-6/8, NO, and PAF promotes systemic vasodilation and increased capillary permeability>intravascular plasma protein loss decreases oncotic forces > additional intravascular fluid loss > toxins and cytokines induce loss of peripheral vascular tone > hypotension > hypoperfusino > septic shock

Question 30

LPS effect on endothelium triggers coag cascade and damages capillaries, which can lead to what two things?

Answer 30

DIC (disseminated intravascular coagulopathy) ARDS (acute respiratory distress syndrome)

Question 31

what can be a result from pathological activation of coagulation due to disseminated intravascular coagulopathy (DIC)?

Answer 31

1. small blood clot form inside blood vessels throughout body 2. consumption of coag proteins and platelets > disruption of normal coag causing abnormal bleeding 3. clots plug normal blood flow to organs > ischemic injury

Question 32

list what could trigger disseminated intravascular coagulopathy (DIC)

Answer 32

bacterial endotoxins, sepsis parasites viruses carcinoma, hemangiosarcoma, leukemia heat stroke, antigen-Ab complexes *diffuse endothelial damage and/or generalized platelet activation initiates

Question 33

define acute respiratory distress syndrome (ARDS)

Answer 33

multifactorial source of injury to respiratory capillary endothelium (primary) epithelium (secondary)

Question 34

list the main causes of acute respiratory distress syndrome (ARDS)

Answer 34

endotoxemia, sepsis, extensive trauma (hit by car), DIC, pancreatitis

Question 35

ID pathology

Answer 35

ARDS blue - inflammatory cells dilated blood vessels

Question 36

Describe the pathogenesis of ARDS

Answer 36

Damaged vessels allow leakage of fibrin and fluid > formation of hyaline membranes (protein, fibrin, surfactant and cell debris) > resolution through scarring

Question 37

*Liz Brain

Question 38

neurogenic shock pathogenesis

Answer 38

trauma, spinal cord injury, fear, electricity > triggers generalized ANS > sympathetic tone lost, parasympathetics dominate > massive peripheral dilation and bradycardia > pooling of blood > hypoperfusion > neurogenic shock

Question 39

what types of microcirculatory shock trigger cytokines and which triggers autonomic discharge?

Answer 39

anaphylactic and endotoxic shock - cytokine neurogenic shock - autonomic discharge

Question 40

describe what occurs at each stage in the development of shock

Answer 40

compensation - increased HR, vasoconstriction, ADH and AII released > increased BP and blood diversion to vital tissue progression - anaerobic metabolism > acidosis > peripheral vasoconstriction cannot be maintained so dilation occurs irreversible - cell and tissue necrosis

Question 41

which of the following stages of shock is reversible?

Answer 41

compensation

Question 42

define cause (etiology) of death

Answer 42

injury or disease that began a sequence of events that ultimately led to death

Question 43

define mechanism (pathogenesis) of death

Answer 43

biochemical or physiological abnormalities that result in death

Question 44

define death

Answer 44

cessation of all vital functions of body - heartbeat, brain activity, and respiration