Cardiovascular Flashcards
layers of vessel wall
Tunica Intima-endothelium, basement membrane
* internal elastic memb
Tunica Media - SM, elastic fibers
Tunica advetentia - areolar connective tissue.
Properties of vascular smooth muscle cells (VSMC)
Contractility
Secretory - ECM, GF, proteases
Plasticity - hypertrophy, prolif, angiogenesis (in response to ischemia, injury)
Virchow triad describes the formation of ___
Thrombosis
Virchow triad:
1) EC injury via HTN, shear stress, turbulent flow, bacterial infection.
2) disruption in laminar flow
3) Hypercoagulability -less frequent
alterations in blood flow occurs in ____ .
- atherosclerotic plaques
- aneurysms
- MI
- mitral valve stenosis
Edema is defined as ___
excess fluid in the interstitial spaces.
What maintains fluid balance inflow/outflow?
- normally, fluid entering arterial end of microcirculation is balanced by inflow into venular end
- excess fluid is drained by lymphatics, which returns to bloodstream via thoracic duct.
Increased Hydrostatic Pressure occurs in ___ (2)
impaired venous drainage, CHF
Decreased Oncotic Pressure occurs due to ___, seen in ____ (3 conditions).
- reduced albumin
- nephrotic syndrome, cirrhosis, protein malnutrition (reduced production of plasma proteins).
Factors that contribute to the development of an infarct:
- presence of alternative blood supply (dual arterial supply–liver, lungs, hands VS. end arterial–renal, splenic)
- rate of development of occlusion - slow growing are less likely to infarct due to dev of alternative flow (pre-existing collaterals),
- vulnerability to hypoxia - neurons, myocardial cells, fibroblasts within myocardium,
- O2 content of blood - anemia, cyanotic patient, C
consequences of a systemic thromboembolism are dependent on ___ and ___.
the collateral supply and caliber (diameter) of the vessel occluded
Infarction is defined as ___
an area of ischemic necrosis due to occlusion of arterial supply or venous drainage.
Endothelium plays secretory and modulatory role for vascular SM tone and platelet function by producing….
vasodilators: NO, PGI2 (prostocyclins).
vasoconstrictors: Endothelin.
keeps platelets from aggregating
keeps vascular SM from doing mitosis
Metabolic role of endothelium includes processing of vasoactive factors including ___ and __
- antiotensin converting enzyme production of Ang II (vasoconstrictor)
- breakdown of bradykinin (inflammation)
Flow through a region is governed mainly by ____
resistance of the microcirculation
Factors that affect blood pressure
P's law: deltaP= RQ = uLQ/r4 *r = radius of vessel is MOST important. R= resistance Q= flow L= length of vessel
3 types of regulation involved with local blood flow
- Metabolic regulation – local metabolites cause vasodilation mostly
- Auto-regulation – transmural pressure (against the wall) causes vasoconstriction mostly
- Shear stress-induced vasodilation– caused by longitudinal pressure gradient
Vascular tone means __, which is controlled by ___ and ___
- state of contractility
- myogenic tone (intrinsic factors)
- Neurologic and Humoral tone (extrinsic factors)-sym neurons
areas of bifurcation are more liekly to have aneurysms due to ___ and ___ induced injury
sheer stress and turbulance
If you increase radius by 2, flow …
r^4 is directly correlated with flow (Q). So if r doubles, flow is 16x higher!
Pressure fluctuations in formation of edema:
- increased hydrostatic pressure or decreased plasma oncotic pressure (colloid onc P) leads to net acccumilation extravascular fluids. Causes edema when lymphatics cant drain this.
4 changes tht can cause edema:
1) INC capillary permeability (burns, allergic inflammation–loss of plasma prot)
2) DEC capillary oncotic pressure (dec plasma prot production– cirrhosis, malnutrition)
3) INC capillary Hydrostatic P (venous obstruction, renal Na/water retention, heart failure)
4) lymph obstruction (cant drain)
Edema points to ___ and ___, which impairs ___ and ____
- underlying disease, inflammation
- inflammation points to impaired wound healing and reduced ability to fight infection.
4 things that can dec CO and lead to edema
- Heart failure
- malnutrition, neohrotic syndrome (dec. prot synth+ BV)
- ascites, other effusions
- primary renal failure
Levels of Renin, AngII, ald, ADH are high in heart failure, why?
to compensate for low CO, by increasing salt and water retention => inc plasma volume.
___ is often the cause of arterial thrombi.
Cardiac dysfunction
Disseminated Intravascular Coagulation
- forming excess clots due of widespread activation of thrombin. Thrombin doesn’t stay localized (everywhere)
- not a primary disease, a complication.
- a “consumptive coagulopathy”– consumes all the clotting factors, so none left to form a clot if there is hemorrhage.
- manage it with anticoagulants and fresh frozen plasma (FFP).
- Widespread ischemia, infarction, hypoperfusion
- decreased fibrinolysis—not enough to keep up with clot formation.
DIC is a major concern during pregnancy bc _____
risk of hemorrhage is high, but not enough clots can be formed in DIC (wasting clotting factors) = blood loss
*Bleeding is a sign of the inability to form a clot
Why do we test for D-dimers to rule out DIC?
3rd step of normal thrombus formation (dissolution, fibrinolytic activity) requires fibrin degradation products (FDP)—particularly D-dimers. But in DIC, there isn’t enough D-diners to keep up with clot formation.
A pulmonary thoromboemboli is most likely to originate from ___
a venous thrombi from a deep vein of the leg.
PE in a (medium/small) vessel is more likely to cause an infarct.
small (mediums have collaterals).
Complications of Pulmonary vs. systemic thromboembolism
PR: sudden death, CV collapse, cor polmonale
Systemic TE: complication in lower extrimities, brain, kidney, spleen (depends on size of vessel and collaterals).
embolism
detached solid, liquid, or gaseous mass (usually a thrombus) travelling throuhgh vessels.
infarct
zone of necrosis caused by blocked venous drainage OR arterial supply.
initiating events for an infarct:
- primarily embolus/thrombus
- local vasospasm
- swelling of a atheroma (hemorrhage within a plaque)
- compression of a vessel (tumor)
concentric vs. eccentric hypertrophy of heart walls
concentric = muscular/buff eccentric = baggy heart
Causes of cardiogenic shock
pump failure due to:
- intrinsic myocardial damage
- ventricular arrhythmias
- outflow obstructions
Causes of hypovolumic shock
- hemorrhage, burns, trauma
Causes of septic shock
Gm Negative endotoxins (bacterial LPS released = inflammation)
Lead to: systemic vasodilation, pump failure/CV collapse, even DIC (EC injury, activation of coagulatory factors)
Causes of neurogenic shock
anesthesia or spinal cord injury causes imbalance bw sympathetic and parasympathetic NS –> massive vasodilation
intimal thickening forms ____. Exaggerated healing response to vascular injury leads to intimal thickening and may result in ____
- neointima (ECM secreted by dedifferentiated SM cells)
- stenosis or occlusion.
a progressive disease characterized by systolic dysfunction and simultaneous enlargement of ALL chambers of the heart
Dilated cardiomyopathy
- ventricular hypertrophy
- strong, hyperkinetic contractions
- impaired diastolic filling.
- This heart is also incapable of stretching, so cannot effectively adjust stroke volume
Hypertrophic cardiomyopathy
asymmetric septal hypertrophy
renal damage and decreased urine output starts in which stage of shock?
progressive stage
- non progressive=compensations maintain perfusion
- irreversible = renal shutdown, acute tubular necrosis. Cannot be corrected by hemodynamics.
individuals with abdominal aortic aneurisms are at risk for ___ and ___
ischemic heart disease and stroke (due to systemic nature of atherosclerosis
most common cause is ____ due to medial destruction, second is ___. Primary type of aneurism ___
- atherosclerosis
- plaque formation in the intima
- abdominal aortic aneurism = most common.
aneurism
- localized abnormal dilation of vessel or heart
- primarily due to weakened wall.
false aneurism vs. dissection
FA = hematoma, extravasation of blood in extravascular connective tissue Dissection = tear in intima, extravasation of blood into the wall, but no dilation.
forward failure vs. backward failure
forward = inadequate CO backward = venous backup
Left side hrt failure can occur due to _____ vs. Rt side failure can occur due to ___
L=Systemic HTN, mitral/aortic valve disease, ischemic heart
R= Left Ventricular failure (with or without pulmonary congestion and disease)
in CHF when sympathetics and myocyte hypertrophy is insufficient to compensate, ___ happens to inc PRELOAD, and achieve ___
dilation = chamber enlargement = inc preload.
Compensated heart failure.
associated with CHF
- backward failure: pulmonary congestion, edema, venous congestion, systemic edema
- dyspnea due to dec lung compliance (congested remember)
- ortopnea due to increased venous return
- may become cyanotic and acidotic.
Amount of activated thrombin > antithrombins in ____
DIC
