BSCI202 Practice LEX-Exam2 + PreQ's EocQ's

For generating active recall and testing real memory

What defines an artery?

A vessel that carries blood away from the heart.

What defines a vein?

A vessel that carries blood toward the heart.

Do all arteries carry oxygen-rich blood?

No; pulmonary arteries carry oxygen-poor blood.

Do all veins carry oxygen-poor blood?

No; pulmonary veins carry oxygen-rich blood.

Which chamber receives systemic venous blood?

Right atrium.

Which vessels empty into the right atrium?

Superior vena cava, inferior vena cava, and coronary sinus.

Which valve connects the right atrium and ventricle?

Tricuspid (right AV) valve.

Which valve connects the right ventricle and pulmonary trunk?

Pulmonary semilunar valve.

Which vessels return oxygenated blood from lungs to heart?

Pulmonary veins.

Which chamber receives pulmonary venous blood?

Left atrium.

Which valve connects the left atrium and left ventricle?

Mitral (bicuspid; left AV) valve.

Which valve connects the left ventricle and aorta?

Aortic semilunar valve.

What is the correct order of the four heart valves along blood flow?

Tricuspid → pulmonary → mitral → aortic.

Trace blood flow from body to lungs.

Venae cavae → RA → tricuspid → RV → pulmonary valve → pulmonary arteries → lungs.

Trace blood flow from lungs to body.

Pulmonary veins → LA → mitral → LV → aortic valve → aorta → body.

Which heart chamber has the thickest myocardium?

Left ventricle.

Why is the left ventricle myocardium thickest?

It must generate high pressure for systemic circulation.

Which circuit is pumped by the right ventricle?

Pulmonary circulation.

Which circuit is pumped by the left ventricle?

Systemic circulation.

What is the myocardium?

Muscular middle layer of the heart wall.

What is the endocardium?

Inner endothelial lining of the heart and valves.

What is the epicardium?

Outer heart wall; visceral layer of serous pericardium.

What is the pericardium?

Protective sac surrounding the heart.

What is the apex of the heart?

Narrow inferior tip, mainly formed by left ventricle.

What is the base of the heart?

Broad superior/posterior aspect where great vessels attach.

What prevents AV valve leaflets from prolapsing into atria?

Chordae tendineae anchored to papillary muscles.

What do papillary muscles do during ventricular systole?

Contract to tense chordae and prevent AV valve prolapse.

Do semilunar valves have chordae tendineae?

No; they close by pressure-driven filling of their cusps.

What determines opening and closing of heart valves?

Pressure differences across the valves.

Why might the mitral valve face greater mechanical stress than tricuspid?

Left ventricular pressure is much higher than right ventricular pressure.

What is systole?

Contraction phase of a heart chamber.

What is diastole?

Relaxation phase of a heart chamber.

When do the atria contract relative to ECG?

After the P wave, mainly during the PR segment.

What does the P wave represent?

Atrial depolarization.

What does the QRS complex represent?

Ventricular depolarization.

What does the T wave represent?

Ventricular repolarization.

What does the PR interval represent?

Start of atrial depolarization to start of ventricular depolarization.

What is the ST segment associated with?

Ventricles remain depolarized; contraction and ejection occur.

What is the QT interval?

Start of ventricular depolarization through ventricular repolarization.

Does a surface ECG directly show SA-node firing?

No; it records summed electrical activity, not a discrete SA-node spike.

Does the P wave represent ventricular depolarization?

No; it represents atrial depolarization.

Does an ECG trace one cardiac cell's action potential?

No; it records summed electrical activity of the heart.

What is the normal cardiac conduction pathway?

SA node → AV node → bundle of His → bundle branches → Purkinje fibers.

Why is AV-node conduction delayed?

Allows atrial contraction and ventricular filling before ventricular contraction.

Can the heart beat without autonomic nerve input?

Yes; autorhythmic pacemaker cells generate impulses intrinsically.

What is the SA node's function?

Primary pacemaker initiating the normal heartbeat.

What causes early slow pacemaker depolarization?

Net inward funny Na+ current and reduced K+ efflux.

What contributes to late pacemaker depolarization?

Transient Ca2+ influx contributes near threshold.

What ion causes the rapid upstroke in SA-node action potentials?

Ca2+ influx through voltage-gated L-type channels.

What causes repolarization of pacemaker cells?

K+ efflux.

Do contractile cardiomyocytes have an unstable resting potential?

No; they normally have a stable resting membrane potential.

What causes phase 0 in ventricular contractile cells?

Rapid Na+ influx.

What causes the plateau phase of ventricular contractile cells?

Ca2+ influx balanced by K+ efflux.

What causes phase 3 repolarization in contractile cardiomyocytes?

K+ efflux as Ca2+ channels inactivate.

Why does cardiac muscle have a plateau phase?

Prolongs refractory period and supports sustained contraction.

What ion triggers cardiac excitation–contraction coupling?

Ca2+ entering through L-type channels triggers SR Ca2+ release.

How is cytosolic Ca2+ lowered during cardiac relaxation?

SERCA returns Ca2+ to SR; NCX and Ca2+ pumps extrude it.

How does sympathetic stimulation affect heart rate?

Increases heart rate (positive chronotropy).

How does sympathetic stimulation affect contractility?

Increases contractility (positive inotropy).

How does epinephrine increase cardiac contractility?

Beta1 signaling enhances Ca2+ entry and handling.

How does parasympathetic vagal stimulation affect heart rate?

Slows SA-node firing and heart rate.

What is the first heart sound S1?

Closure of AV valves at start of ventricular systole.

What is the second heart sound S2?

Closure of semilunar valves at start of ventricular diastole.

What is isovolumetric contraction?

Ventricles contract with all valves closed; pressure rises, volume constant.

What marks the start of right ventricular isovolumetric contraction?

Tricuspid valve closes.

When do semilunar valves open?

When ventricular pressure exceeds arterial pressure.

When do AV valves open?

When ventricular pressure falls below atrial pressure.

What is isovolumetric relaxation?

Ventricles relax with all valves closed; pressure falls, volume constant.

What is the basic cardiac cycle sequence after ventricular relaxation?

AV open → filling → atrial systole → AV close → isovolumetric contraction → SL open → ejection → SL close.

What is end-diastolic volume (EDV)?

Blood volume in ventricle at end of filling.

What is end-systolic volume (ESV)?

Blood remaining in ventricle after ejection.

What is stroke volume (SV)?

Volume ejected by one ventricle per beat; SV = EDV − ESV.

What is cardiac output (CO)?

Blood pumped by one ventricle per minute; CO = HR × SV.

What is ejection fraction?

EF = SV / EDV × 100%.

What is preload?

Ventricular stretch at end of diastole, related to EDV.

What is afterload?

Load/pressure the ventricle must overcome to eject blood.

How does increased afterload acutely affect SV?

Usually decreases stroke volume if other factors are unchanged.

How does increased contractility affect SV?

Increases SV at the same preload and afterload.

What is the Frank–Starling mechanism?

More filling stretches myocardium and increases force/SV within limits.

What is systolic blood pressure?

Peak arterial pressure during ventricular systole.

What is diastolic blood pressure?

Lowest arterial pressure during ventricular diastole.

How do you calculate pulse pressure?

Systolic pressure − diastolic pressure.

What is pulse pressure for 120/60 mmHg?

60 mmHg.

What is an approximate mean arterial pressure formula?

MAP ≈ DBP + (SBP − DBP)/3 at normal heart rates.

What is the main function of elastic arteries?

Pressure reservoirs that sustain flow during diastole.

What is the main function of arterioles?

Variable resistance vessels controlling tissue perfusion.

Which vessels are the major blood-volume reservoir?

Systemic veins.

Which vessels have high tunica-media-to-wall proportion?

Arterioles, with prominent smooth muscle relative to size.

What is the main structural layer of capillary walls?

Simple squamous endothelial cells with basal lamina.

Which capillary type predominates in alveolar walls?

Continuous capillaries.

What is the function of capillaries?

Exchange gases, nutrients, and wastes with tissues.

What is the approximate blood volume distribution in veins?

About 64% in the provided course example.

What is the approximate blood volume distribution in lungs?

About 9% in the provided course example.

What is the approximate blood volume distribution in small arteries/arterioles?

About 8% in the provided course example.

What is the approximate blood volume distribution in large arteries?

About 7% in the provided course example.

What is the approximate blood volume distribution in heart (diastole)?

About 7% in the provided course example.

What is the approximate blood volume distribution in capillaries?

About 5% in the provided course example.

How does vasodilation affect vascular resistance?

Decreases resistance.

How does vasoconstriction affect vascular resistance?

Increases resistance.

How does increased blood viscosity affect resistance?

Increases resistance.