Applied Pathophysiology Exam 2 | Chapter 25
Circulation & Cardiac Output | Actual Exam Q&A
Latest Update Verified and A+ Graded Answers
Circulation & Anatomy
Systemic circulation route
Left heart → aorta → systemic arteries → tissues → systemic veins → right heart
Pulmonary circulation route
Right heart → pulmonary arteries → lungs → pulmonary veins → left heart
Which side of circulation is low pressure?
Pulmonary
Which vessels are capacitance vessels?
Veins (thin-walled, highly compliant)
Which vessels are resistance vessels?
Arterioles
Cardiac Cycle & Output
What happens during diastole?
Ventricles relax and fill; AV valves open, semilunar closed
What produces the first heart sound (S1)?
Closure of AV valves at onset of systole
What produces the second heart sound (S2)?
Closure of semilunar valves at end of systole
What is cardiac output?
Amount of blood pumped each minute = HR × SV
Define preload
Volume stretching ventricle at end-diastole (venous return)
, Define afterload
Pressure ventricle must overcome to eject blood
Define contractility
Intrinsic squeezing power of the ventricle
State Frank-Starling law
Within limits, ↑ preload → ↑ stroke volume due to better fiber overlap
What is the effect of excessive preload?
Fibers overstretched → ↓ stroke volume
Regulation
Effect of SNS on heart
↑ HR and ↑ contractility; venoconstriction ↑ preload; arteriolar constriction ↑ afterload/BP
Role of RAAS
Ang II vasoconstricts & aldosterone retains Na⁺/water → ↑ preload & afterload
Hemodynamics
Main site of greatest resistance in systemic circulation
Arterioles
Typical systemic arterial pressure
~120/80 mm Hg
Typical pulmonary arterial pressure
~25/8 mm Hg
Laplace's Law formula
Wall tension = (Pressure × radius) ÷ (2 × wall thickness)
Clinical significance of Laplace's Law
Larger, thinner-walled high-pressure vessels (e.g., aneurysm) more likely to rupture
Chapter 26
Lipids & Atherosclerosis
Circulation & Cardiac Output | Actual Exam Q&A
Latest Update Verified and A+ Graded Answers
Circulation & Anatomy
Systemic circulation route
Left heart → aorta → systemic arteries → tissues → systemic veins → right heart
Pulmonary circulation route
Right heart → pulmonary arteries → lungs → pulmonary veins → left heart
Which side of circulation is low pressure?
Pulmonary
Which vessels are capacitance vessels?
Veins (thin-walled, highly compliant)
Which vessels are resistance vessels?
Arterioles
Cardiac Cycle & Output
What happens during diastole?
Ventricles relax and fill; AV valves open, semilunar closed
What produces the first heart sound (S1)?
Closure of AV valves at onset of systole
What produces the second heart sound (S2)?
Closure of semilunar valves at end of systole
What is cardiac output?
Amount of blood pumped each minute = HR × SV
Define preload
Volume stretching ventricle at end-diastole (venous return)
, Define afterload
Pressure ventricle must overcome to eject blood
Define contractility
Intrinsic squeezing power of the ventricle
State Frank-Starling law
Within limits, ↑ preload → ↑ stroke volume due to better fiber overlap
What is the effect of excessive preload?
Fibers overstretched → ↓ stroke volume
Regulation
Effect of SNS on heart
↑ HR and ↑ contractility; venoconstriction ↑ preload; arteriolar constriction ↑ afterload/BP
Role of RAAS
Ang II vasoconstricts & aldosterone retains Na⁺/water → ↑ preload & afterload
Hemodynamics
Main site of greatest resistance in systemic circulation
Arterioles
Typical systemic arterial pressure
~120/80 mm Hg
Typical pulmonary arterial pressure
~25/8 mm Hg
Laplace's Law formula
Wall tension = (Pressure × radius) ÷ (2 × wall thickness)
Clinical significance of Laplace's Law
Larger, thinner-walled high-pressure vessels (e.g., aneurysm) more likely to rupture
Chapter 26
Lipids & Atherosclerosis
