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117 Cards in this Set
- Front
- Back
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Cardiomegaly is defined as a cardiothoracic ratio above what percent?
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50%
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How is Doppler assessment useful in an echo of the heart?
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Can give insight on valvular insufficiency or stenosis (look at velocity of blood flow)
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What is the relationship between ejection fraction and mortality?
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Strong inverse relationship
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What is the most cost effective and highest yield modality used to look at left ventricular size and function?
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Echocardiography
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What is the downside of cardiac catheterization?
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Invasiveness
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What is the most accurate modality used to measure ejection fraction?
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Radionuclide ventriculography
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What is the CT calcium score?
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Shows relationship between calcium score and obstructive coronary artery disease/mortality (direct relationship)
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ST segment ELEVATION is usually indicative of what?
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MI
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ST segment DEPRESSION is usually indicative of what?
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Ischemia
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What radionuclide agents are used in SPECT?
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Thalium
Sestamibi |
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What is an advantage of trans-esophageal echo over trans-thoracic?
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Trans-esophageal can give better quality images, especially of posterior cardiac structures
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What are the Gorlin and Hakki equations used for?
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To calculate valve area
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Balloon valvuloplasty can be used to fix what abnormality?
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Stenosis
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How can SPECT be used to determine whether or not there has been an ischemic event?
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Isotopes can only enter functioning, non-ischemic cells
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What is the key variable in circulation that drives perfusion to organs?
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Mean arterial pressure
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Why are feedback mechanisms important?
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Maintains blood pressure
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Regulation of perfusion is due to altering what?
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Resistance to vascular beds
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What 5 factors drives maintenance of BP?
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SNS and PNS
Intrinsic factors of heart Kidney, adrenal, pituitary glands |
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Which vessels are considered the workhorse of the vasculature system?
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Arterioles
Capillaries Venules |
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Which vessel is the major site of resistance?
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Arterioles
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What is the major mechanism for changing blood flow?
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Changing resistance (by changing diameter of vessels)
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Viscosity is dependent upon velocity in what types of fluids?
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Non-Newtonian fluids
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What is the relationship between velocity and viscosity of non-Newtonian fluids.
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The faster the shear rate, the lower the viscosity
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What is the relationship between hematocrit and viscosity?
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Direct relationship
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What does Reynold's number determine?
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Probability that there will be turbulent flow
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What does a Reynold's number of >3000 mean?
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Turbulent flow
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What does a Reynold's number of <2000 mean?
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Laminar flow
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What are the two biggest influences on Reynold's number?
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Viscosity
Velocity |
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Where are 5HT1 receptors found?
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Endothelial cells of peripheral blood vessels
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What happens when 5HT1 receptors are stimulated?
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Release of NO
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What happens when 5HT1B and 5HT1D receptors are stimulated?
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Inhibition of adenyl cyclase
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Where are 5HT1B receptors found?
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Subiculum
Substantia nigra |
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Where are 5HT1D receptors found?
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Cranial blood vessels
Presynaptic nerve terminals |
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Which serotonin receptor is an autoreceptor?
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5HT1B
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What happens when 5HT2A is activated?
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Activation of PLC
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Where are 5HT2A receptors found?
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Platelets
Vascular smooth muscle Cerebral cortex |
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What is the function of 5HT2A receptors?
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Platelet aggregation
Contraction and vasoconstriction |
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Thrombus formation can be activated by which serotonin receptor?
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5HT2A
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Sumatriptan is used to treat what?
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Migraines
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What is the mechanism of sumatriptan?
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5HT1B and 5HT1D agonist
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What amino acid is the precursor to seratonin?
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Tryptophan
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What amino acid is the precursor to catecholamines?
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Tyrosine
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What type of reactions does histamine mediate?
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Anaphylaxis
GI secretions Inflammation |
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How does the turnover rate differ for histamine found in mast cells and basophils versus free histamine?
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Free histamine has faster turnover rate
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In which tissues is free histamine usually found?
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Skin
CNS Stomach |
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In which tissues are mast cells with histamine usually found?
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Skin
Bronchial and intestinal mucosa Blood |
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How does cAMP influence histamine release?
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Decreases histamine release
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How does cGMP influence histamine release?
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Increases histamine release
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What happens in histamine shock?
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Fall in BP
Increased vascular permeability leading to decreased blood volume, decreased venous return and decreased cardiac output |
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How do solvents and solutes move across capillary membranes?
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Diffusion
Filtration Pinocytosis |
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What is the normal net filtration rate of the entire body?
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2ml/min
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What factors will increase the filtration factor (Kf)?
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Burn injury
Inflammation |
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What is microcirculation?
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Site of local blood vessel regulation (consists of arterioles, capillaries and venules)
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Acute local control occurs in what time period?
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Seconds to minutes
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Chronic local control occurs in what time period?
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Days to weeks to months
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Autoregulation is most pronounced in what organs?
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Brain and kidney
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Autoregulation ensures that what remains constant?
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Blood flow
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What is a stimulus for angiogenesis?
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Ischemia
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What is the promotor for angiogenesis?
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VEGF
Hypoxia induced factor-1 |
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How do angiogenesis and arteriogenesis compare in length of process?
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Angiogenesis-days
Arteriogenesis-days to weeks |
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What is arteriogenesis?
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Development of collateral blood flow
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What induces arteriogenesis?
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Increased shear stress
Inflammation |
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What is the promotor for arteriogenesis?
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Shear stress responsive element
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What are some factors that are involved in both angiogenesis and arteriogenesis?
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VEGF
FGF PDGF GM-CSF MCP-1 (monocyte chemoattractant protein) |
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What determines that size of contraction of the vessel?
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Smooth muscle
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How does smooth muscle communicate with one another?
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Through gap junctions
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What is the effect of magnesium on contraction?
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Causes vasodilation
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Why does magnesium cause vasodilation?
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Competes with calcium
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What effect does increased sodium ion have on contraction?
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Mild arteriolar vasodilation
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Why does increased sodium ion cause vasodilation?
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Increase in osmolality
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What effects does carbon dioxide have locally and systemically?
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Locally-vasodilation
Systemically-vasoconstriction |
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What effects on contraction do activators of adenylate cyclase (ie epi) have on smooth muscle?
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Vasodilation
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Why does epinephrine cause vasodilation of vessels?
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Activates adenylate cyclase, which phosphorylates MLCK so it cannot phosphorylate myosin to allow formation of cross bridges
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Where are high pressure baroreceptors located?
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Carotid sinus
Aortic arch |
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Where are low pressure baroreceptors located?
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Atria
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What do low pressure baroreceptors detect?
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Changes in venous pressure/blood volume
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What do high pressure baroreceptors detect?
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Changes in arterial pressure
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What is the difference between A and B low pressure baroreceptors?
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A receptors fire during atrial systole
B receptors fire during atrial diastole |
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Where are chemoreceptors located?
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Carotid and aortic bodies
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Where are receptors that are associated with the dive reflex located?
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Nasopharynx
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How is the dive reflex activated?
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Water
Smoke |
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What activates the Cushing reflex?
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Increase in intracranial pressure
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Where are Cushing reflex receptors found?
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Brainstem
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An acute hypertensive crisis can occur due to activation of what reflex?
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Cushing reflex
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The Cushing reflex is activated for what purpose?
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Increases arterial pressure to maintain CNS perfusion
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Why are baroreflex activation short lived?
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Resetting of baroreceptors
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What are the four classes of eicosanoids?
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Prostaglandins
Leukotrienes Epoxides Thromboxanes |
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Dexamethasone and other glucocorticoids can inhibit which COX isoform?
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COX-2
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Leukotriene antagonists are useful treatments for what?
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Asthma--causes broncodilation and decreased inflammation
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What enzyme leads to the formation of leukotrienes?
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5-lipoxygenase
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What is the mechanism of action of epoxides?
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Causes vasodilation through hyperpolarization
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What amino acid is NO derived from?
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L-arginine
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How is NO activated?
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Shear force
Binding of agents to endothelial receptors |
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What agents can be associated in the final pathway of NO production?
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Ach
Histamine Bradykinin Substance P ATP |
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What are the three isoforms of nitric oxide synthase (NOS)
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Constitutive
Neural Inducible |
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What is the role of PDE-5?
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Breaks down nitric oxide
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What is the mechanism of action of nitroglyceride and sodium nitroprusside?
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Cause release of NO
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What is nitroglyceride prescribed for?
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Treatment of angina
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What is sodium nitroprusside prescribed for?
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Immediate control of high BP
CHF |
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What is the action of bradykinin?
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Vasodilation
Venoconstriction Increase in capillary permeability |
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What does B1 (bradykinin) receptor do?
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Upregulated during inflammation
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What does B2 (bradykinin) receptor do?
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Associated with NOS and PLA2 activity to increase production of NO and prostacyclin
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What effect is seen when ATP interacts with P2y receptor?
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Vasodilation through stimulation of NO and prostacyclin release
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Endothelin can cause vasodilation by interaction with what receptor?
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ETB
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What is cardiometabolic syndrome?
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Series of conditions, that when occurring together, increase risk of HTN and heart disease
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What is the best treatment of cardiometabolic syndrome?
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Weight loss with exercise
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What is cardiometabolic syndrome?
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Series of conditions, that when occurring together, increase risk of HTN and heart disease
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What is the best treatment of cardiometabolic syndrome?
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Weight loss with exercise
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What factors affect filling pressure?
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Blood volume
Venous tone |
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What happens to renal flow when you decrease blood pressure?
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Renal flow decreases
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What is the relationship between aldosterone and angiotensin II?
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Angiotensin II stimulates the release of aldosterone
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How does sodium and water retention increase cardiac output?
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Increases blood volume --> increased cardiac output
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Through what pathways is blood pressure maintained?
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Sympathetic nervous system
Renin-angiotensin system Vasopressin |
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What happens to vascular permeability in histamine shock?
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Increased vascular permeability
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Torsades de pointes is associated with what syndrome?
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Long QT
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Where are H1/H2 receptors found?
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Periphery and CNS
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Where are H3/H4 receptors found?
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CNS
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