67 Questions
Which structure allows blood to flow directly from the right atrium to the left atrium, bypassing the right ventricle?
Foramen ovale
What is the postnatal derivative of the umbilical vein?
Ligamentum teres hepatis
Which vein carries blood with high oxygen saturation from the placenta to the fetus?
Umbilical vein
What is the fate of the ductus arteriosus after birth?
Ligamentum arteriosum
Where does the blood from the superior vena cava travel to in fetal circulation?
Right atrium
Which fetal structure transforms into the median umbilical ligament after birth?
Allantois
At what week of development does the heart begin to beat spontaneously in vertebrate embryos?
Week 4
What structure develops to maintain right-to-left shunt in the heart during septation?
Foramen ovale
When do the septum primum and septum secundum typically fuse completely?
During infancy/childhood
What is the main consequence of a patent foramen ovale?
Inadequate oxygenation (cyanosis)
What is a potential risk associated with atrial septal defects (ASD)?
Stroke
Which structure grows towards the endocardial cushions during septation of the chambers?
Septum primum
What is the formula for resistance in a blood vessel?
ΔΡ / 8η × length / πr⁴
How does the resistance of blood vessels vary with the radius?
R α 1/r⁴
Which blood vessels have the highest total cross-sectional area and the lowest flow velocity?
Capillaries
Which of the following accounts for most of the total peripheral resistance (TPR) in the circulatory system?
Arterioles
What happens to viscosity in hyperproteinemic states?
Viscosity increases
What changes in venous return alter stroke volume (SV) and cardiac output (CO)?
Changes in circulating volume
What is an example of a positive inotropic agent?
Milrinone
How does exercise affect total peripheral resistance (TPR)?
Decreases TPR
Which part of the heart is the most posterior?
Left atrium
What symptom can enlargement of the left atrium cause due to compression of the left recurrent laryngeal nerve?
Hoarseness
Which layer of the pericardium is innervated by the phrenic nerve?
Fibrous pericardium
Which artery most commonly supplies the AV and SA nodes?
Right coronary artery
In right-dominant circulation, which artery does the posterior descending artery arise from?
Right coronary artery
Which artery is most commonly occluded in coronary artery disease?
Left anterior descending artery
Where does the coronary sinus drain into?
Right atrium
What percentage of the inferior (diaphragmatic) surface of the heart does the left ventricle comprise?
2/3
What forms the membranous interventricular septum?
Aorticopulmonary septum rotating
Which structure is derived from the endocardial cushions of the outflow tract?
Aortic valve
Which congenital cardiac anomaly is most common?
Ventricular septal defect
What artery is derived from the 4th aortic arch on the right side?
Proximal part of right subclavian artery
What structure contributes to the formation of both the atrial and ventricular septa?
Endocardial cushions
The 3rd aortic arch gives rise to which arteries?
Common carotid artery and proximal part of the internal carotid artery
Which condition is NOT associated with the failure of neural crest cells to migrate?
Ebstein anomaly
What does the 1st aortic arch become?
Maxillary artery
Which equation correctly represents stroke volume?
SV = EDV - ESV
What does the Fick principle for cardiac output (CO) involve?
Rate of O2 consumption divided by (arterial O2 content - venous O2 content)
Which factor directly influences pulse pressure (PP)?
Stroke volume (SV) and arterial compliance
How is mean arterial pressure (MAP) calculated using cardiac output (CO) and total peripheral resistance (TPR)?
MAP = CO * TPR
Which condition is associated with an increase in pulse pressure (PP)?
Aortic regurgitation
In which situation would you observe a decreased pulse pressure (PP)?
Heart failure
What is the effect of increased heart rate (HR) on diastole?
Shortens diastolic filling time
How is cardiac output (CO) maintained in the later stages of exercise?
Increased heart rate (HR) only
Which factor is proportional to the force of contraction of the heart?
End-diastolic length of muscle fiber (preload)
Which of the following is a positive inotrope?
Dobutamine
Which embryonic structure gives rise to the ascending aorta and pulmonary trunk?
Truncus arteriosus
What does the primitive ventricle give rise to?
Trabeculated part of left and right atria
Which veins contribute to the formation of the inferior vena cava (IVC)?
Posterior cardinal, subcardinal, and supracardinal veins
What does the endocardial cushion give rise to?
Atrial septum, membranous interventricular septum, AV and semilunar valves
Which structure gives rise to both atria?
Primitive heart tube
Which of the following conditions is associated with an increased preload?
Early pregnancy
What is the main factor that approximates afterload?
Mean arterial pressure (MAP)
Which medication is known to decrease afterload?
ACE inhibitors
Which of the following increases myocardial oxygen demand?
Increased afterload
Which of the following substances increases contractility by inhibiting the Na+/K+ pump?
Digoxin
Which condition is likely to decrease contractility?
Beta-blockade
What defines wall stress in the context of Laplace's law?
Pressure x radius / 2 x wall thickness
Which of the following decreases preload?
Nitroglycerin
During which phase does the period of highest oxygen consumption occur?
Isovolumetric contraction
What heart sound is associated with the rapid ventricular filling phase?
S3
Which heart sound is normally loudest at the mitral area?
S1
When does the 'v wave' in the jugular venous pulse occur?
Increased RA pressure due to volume against closed tricuspid valve
In which condition is the S4 heart sound commonly found?
Hypertrophy
Which phase of the cardiac cycle immediately follows the aortic valve closing?
Isovolumetric relaxation
What does the 'x descent' in the jugular venous pulse signify?
Atrial relaxation and downward displacement of closed tricuspid valve
Which heart sound is heard during late diastole?
S4
Study Notes
Embryonic Structure and Development
- Truncus arteriosus gives rise to ascening aorta and pulmonary trunk
- Bulbus cordis gives rise to smooth parts (outflow tract) of left and right ventricles
- Primitive ventricle gives rise to trabeculated part of left and right atria
- Endocardial cushion gives rise to atrial septum, membranous interventricular septum, AV and semilunar valves
- Right common cardinal vein and right anterior cardinal vein give rise to superior vena cava (SVC)
- Posterior cardinal, subcardinal, and supracardinal veins give rise to inferior vena cava (IVC)
- Primitive heart tube gives rise to both atria
- Sinus horn gives rise to right aortic roots
- Aortic roots give rise to left aortic roots
- Pericardial sac gives rise to pericardium
- Sinoatrial node gives rise to SA node
- Atrioventricular node gives rise to AV node
- Primitive ventricles give rise to ventricles
Cardiac Output Equations
- Stroke volume (SV) is equal to EDV - ESV
- Ejection fraction (EF) is equal to SV / EDV = (EDV - ESV) / EDV
- Cardiac output (CO) is equal to SV * HR
- Fick principle: CO = (rate of O2 consumption) / (arterial O2 content - venous O2 content)
- Pulse pressure (PP) is equal to systolic blood pressure (SBP) - diastolic blood pressure (DBP)
- Mean arterial pressure (MAP) is equal to CO * total peripheral resistance (TPR)
Starling Curves
- Normal (exercise)
- Normal (rest)
- Heart failure + positive inotrope
- Myocardial contractility
- Heart failure
Cardiovascular Physiology
- Isovolumetric contraction is the period between mitral valve closing and aortic valve opening
- Systolic ejection is the period between aortic valve opening and closing
- Isovolumetric relaxation is the period between aortic valve closing and mitral valve opening
- Rapid filling is the period just after mitral valve opening
- Reduced filling is the period just before mitral valve closing
Cardiac Cycle
- S1: mitral and tricuspid valve closure, loudest at mitral area
- S2: aortic and pulmonary valve closure, loudest at left upper sternal border
- S3: in early diastole during rapid ventricular filling phase, best heard at apex with patient in left lateral decubitus position
- S4: in late diastole ("atrial kick"), best heard at apex with patient in left lateral decubitus position
Jugular Venous Pulse (JVP)
- a wave: atrial contraction, prominent in AV dissociation (cannon a wave), absent in atrial fibrillation
- c wave: RV contraction (closed tricuspid valve bulging into atrium)
- x descent: atrial relaxation and downward displacement of closed tricuspid valve during rapid ventricular ejection phase, reduced or absent in tricuspid regurgitation and right HF
- v wave: increased RA pressure due to volume against closed tricuspid valve
- y descent: RA emptying into RV, prominent in constrictive pericarditis, absent in cardiac tamponade
Resistance, Pressure, Flow
- Volumetric flow rate (Q) is equal to flow velocity (v) x cross-sectional area (A)
- Resistance is equal to driving pressure (ΔΡ) / 8η (viscosity) x length / πr4
- Q α r4
- R α 1/r4
- Total resistance of vessels in series: R = R1 + R2 + R3 +...
- Total resistance of vessels in parallel: 1/R = 1/R1 + 1/R2 + 1/R3 +...
Cardiac and Vascular Function Curves
- Inotropy: changes in contractility → altered SV → altered CO/VR and RA pressure (RAP)
- Venous Return: changes in circulating volume → altered RAP → altered SV → change in CO
- Total Peripheral Resistance: changes in TPR → altered CO, change in RAP unpredictable
This quiz covers the formation of different heart structures from embryonic components. Learn about the development of aorta, ventricles, atria, and valves from their embryonic origins.
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