USMLE Step 1 - uWorld High Yield Notes
QUESTIONS AND VERIFIED CORRECT
ANSWERS GRADED A+ LATEST 100%
GUARANTEED PASS
What is the pulmonary capillary wedge pressure and what does it indirectly measure? -
CORRECT ANSWER-Pressure in the pulmonary artey distal to the point of its occlusion by an
inflated intravascular balloon.
Since there's no significant blood flow towards the left atrium (LA) beyong this point of
occlusion, the pressure at the tip of the "wedged" pulmonary artery catheter is an indirect
measurement of LA Pressure.
What would we expect, in a normal patient, the relationship to be between LA and LV pressure
during diastole? - CORRECT ANSWER-We would expect them to be nearly equale (both <12)
since the open mitral valve offers minimal resistance to flow between the 2 chambers
What is the characteristic finding via cardiac catheterization in a patient with mitral valve
stenosis? I.e., if we see what value elevated while the other remains normal, when do we think
"Mitral Valve Stenosis." - CORRECT ANSWER-Cardiac Catheterization will reveal a LA end
diastolic pressure (via pulmonary capillary wedge pressure) that is significantly greater than the
LV end diastolic pressure (LVEDP).
This abnormal pressure gradient implies increased resistance to flow between the LA and LV,
i.e., mitral valve stenosis.
,Summarize the key points of pulmonary capillary wedge pressures (PCWP) and how it helps us
diagnose mitral valve stenosis. - CORRECT ANSWER-The Pulmonary capillary wedge pressure
(PCWP) measures LAEDP. Under normal conditions, the LAEDP is nearly equal to the LVEDP.
Mitral stenosis eleveates the LAEDP and PCWP relative to the LVEDP.
Generally speaking, regarding blood flow through our vessels, the law of conservation of mass
states that the total flow of mass into a contained system must be equal to the total outflow of
mass from that system in a steady state.
What equation helps us prove the following condition: to maintain a constant fluid flow
througha tube with varying diametes, how are cross-sectional area and flow velocities related? -
CORRECT ANSWER-Volume in must equal volume out, right? Vol(in) = A1 * V1 ; Vol(out) =
A2*V2
So any rearrangement of that equation holds true in a physiological system.
A2 = A1*V1 / V2 for example, works.
This applies for blood flow in the cardiovascular system.
What do you think when you hear a patient who has a heart murmur presenting with the
following physical exam findings:
Bounding femoral pulses, carotid pulsations accompanied by head-bobbing. - CORRECT
ANSWER-Aortic Regurgitation
How does the pathophysiology of aortic regurgitation explain the characteristic findings of these
patients? And what are those findings again (2 major ones)? - CORRECT ANSWER-(1) Bounding
femoral pulses;
,(2) Carotid Pulsations with head-bobbing (de Musset sign)
There is a large LVSV, a large regurgitant SV, and a large pulse pressure.
Bounding femoeral and carotid pulses marked by abrupt distention and quick collapse ("water
hammer" pulses) are the result of large pulse pressure
the head bobbing is due to the transfer of mementum from htel arge left ventricular stroke
volume to the head and neck
What is the order of cardiac tissue conduction velocity from *fastest* to *slowest*? - CORRECT
ANSWER-Purkinje System
Atrial Muscle
Ventricular Muscle
AV node
What is the mnemonic to help you remember the order of cardiac tissue conduction velocity? -
CORRECT ANSWER-P ark (purkinje's)
AT (atria)
VENT ura (ventricles)
AV enue (AV node)
Where does Atrial Natriuretic Peptide (ANP) come from? In response to what? - CORRECT
ANSWER-Atrial Cardiomyocytes in response to atrial stretch, it is a signifier of volume expansion
What is the ultimate action of ANP? - CORRECT ANSWER-Lowers blood pressure through
peripheral vasodilation, natriuresis, and diuresis.
, How does ANP affect the following organs:
(1) kidney?
(2) adrenal gland?
(3) blood vessels? - CORRECT ANSWER-(1) Dilates the afferent arterioles, increasing GFR and
urinary excretion of sodium and water (diuresis); also limits sodium reabsorption (in proximal
tubule) and inhibits renin secretion
(2) restricts aldosterone secretion --> increase in sodium and water excretion by the kidneys
(3) relaxes vascular smooth mucles, producing vasodilation; also increases capillary
permeability, leading to fluid extravasation to the interstitium and a decrease in circulating
blood volume
What major hormone comes from the renal juxtaglomerular cells, and what is its net effect on
the vasculature? - CORRECT ANSWER-Renin, which catalyzes angiotensinogen --> ang I
angiotensin causes vasoconstriction, increased blood pressure, and aldosterone release
What is the pathophysiology of CHF in general terms? - CORRECT ANSWER-CHF occurs when
the heart is unable to pump sufficient amounts of blood to meet body's metabolic demands
How is the reduced cardiac output in CHF initially detected? How does the body attempt to
compensate? - CORRECT ANSWER-A drop in blood pressure
Compensatory neurohormonal stimulation that is directed at maintaining blood pressure and
tissue perfusion
Chiefly mediated through:
(1)increased sympathetic nervous system activity,
QUESTIONS AND VERIFIED CORRECT
ANSWERS GRADED A+ LATEST 100%
GUARANTEED PASS
What is the pulmonary capillary wedge pressure and what does it indirectly measure? -
CORRECT ANSWER-Pressure in the pulmonary artey distal to the point of its occlusion by an
inflated intravascular balloon.
Since there's no significant blood flow towards the left atrium (LA) beyong this point of
occlusion, the pressure at the tip of the "wedged" pulmonary artery catheter is an indirect
measurement of LA Pressure.
What would we expect, in a normal patient, the relationship to be between LA and LV pressure
during diastole? - CORRECT ANSWER-We would expect them to be nearly equale (both <12)
since the open mitral valve offers minimal resistance to flow between the 2 chambers
What is the characteristic finding via cardiac catheterization in a patient with mitral valve
stenosis? I.e., if we see what value elevated while the other remains normal, when do we think
"Mitral Valve Stenosis." - CORRECT ANSWER-Cardiac Catheterization will reveal a LA end
diastolic pressure (via pulmonary capillary wedge pressure) that is significantly greater than the
LV end diastolic pressure (LVEDP).
This abnormal pressure gradient implies increased resistance to flow between the LA and LV,
i.e., mitral valve stenosis.
,Summarize the key points of pulmonary capillary wedge pressures (PCWP) and how it helps us
diagnose mitral valve stenosis. - CORRECT ANSWER-The Pulmonary capillary wedge pressure
(PCWP) measures LAEDP. Under normal conditions, the LAEDP is nearly equal to the LVEDP.
Mitral stenosis eleveates the LAEDP and PCWP relative to the LVEDP.
Generally speaking, regarding blood flow through our vessels, the law of conservation of mass
states that the total flow of mass into a contained system must be equal to the total outflow of
mass from that system in a steady state.
What equation helps us prove the following condition: to maintain a constant fluid flow
througha tube with varying diametes, how are cross-sectional area and flow velocities related? -
CORRECT ANSWER-Volume in must equal volume out, right? Vol(in) = A1 * V1 ; Vol(out) =
A2*V2
So any rearrangement of that equation holds true in a physiological system.
A2 = A1*V1 / V2 for example, works.
This applies for blood flow in the cardiovascular system.
What do you think when you hear a patient who has a heart murmur presenting with the
following physical exam findings:
Bounding femoral pulses, carotid pulsations accompanied by head-bobbing. - CORRECT
ANSWER-Aortic Regurgitation
How does the pathophysiology of aortic regurgitation explain the characteristic findings of these
patients? And what are those findings again (2 major ones)? - CORRECT ANSWER-(1) Bounding
femoral pulses;
,(2) Carotid Pulsations with head-bobbing (de Musset sign)
There is a large LVSV, a large regurgitant SV, and a large pulse pressure.
Bounding femoeral and carotid pulses marked by abrupt distention and quick collapse ("water
hammer" pulses) are the result of large pulse pressure
the head bobbing is due to the transfer of mementum from htel arge left ventricular stroke
volume to the head and neck
What is the order of cardiac tissue conduction velocity from *fastest* to *slowest*? - CORRECT
ANSWER-Purkinje System
Atrial Muscle
Ventricular Muscle
AV node
What is the mnemonic to help you remember the order of cardiac tissue conduction velocity? -
CORRECT ANSWER-P ark (purkinje's)
AT (atria)
VENT ura (ventricles)
AV enue (AV node)
Where does Atrial Natriuretic Peptide (ANP) come from? In response to what? - CORRECT
ANSWER-Atrial Cardiomyocytes in response to atrial stretch, it is a signifier of volume expansion
What is the ultimate action of ANP? - CORRECT ANSWER-Lowers blood pressure through
peripheral vasodilation, natriuresis, and diuresis.
, How does ANP affect the following organs:
(1) kidney?
(2) adrenal gland?
(3) blood vessels? - CORRECT ANSWER-(1) Dilates the afferent arterioles, increasing GFR and
urinary excretion of sodium and water (diuresis); also limits sodium reabsorption (in proximal
tubule) and inhibits renin secretion
(2) restricts aldosterone secretion --> increase in sodium and water excretion by the kidneys
(3) relaxes vascular smooth mucles, producing vasodilation; also increases capillary
permeability, leading to fluid extravasation to the interstitium and a decrease in circulating
blood volume
What major hormone comes from the renal juxtaglomerular cells, and what is its net effect on
the vasculature? - CORRECT ANSWER-Renin, which catalyzes angiotensinogen --> ang I
angiotensin causes vasoconstriction, increased blood pressure, and aldosterone release
What is the pathophysiology of CHF in general terms? - CORRECT ANSWER-CHF occurs when
the heart is unable to pump sufficient amounts of blood to meet body's metabolic demands
How is the reduced cardiac output in CHF initially detected? How does the body attempt to
compensate? - CORRECT ANSWER-A drop in blood pressure
Compensatory neurohormonal stimulation that is directed at maintaining blood pressure and
tissue perfusion
Chiefly mediated through:
(1)increased sympathetic nervous system activity,
