Cardiovascular prep

Question 1

Which of the following best describes the cardiovascular system of birds and mammals?

Answer 1

B. Closed circulation, double circuit, no mixing of oxygenated & de-oxygenated blood

Question 2

Which part of the heart forms the apex?

Answer 2

D. Left ventricle

Question 3

Which valve opens when pressure in the right atrium exceeds that in the right ventricle?

Answer 3

C. Right atrioventricular (tricuspid) valve

Question 4

During which phase of the cardiac cycle are all valves closed, but the ventricles are contracting?

Answer 4

C. Isovolumetric contraction

Question 5

A murmur heard between the first and second heart sounds likely indicates:

Answer 5

B. Valvular insufficiency during systole

Question 6

Which of the following combinations results in the greatest cardiac output?

Answer 6

C. HR = 100 bpm, SV = 70 mL

Question 7

The Frank-Starling mechanism describes:

Answer 7

B. An increase in stroke volume due to increased preload

Question 8

Which of the following best describes preload?

Answer 8

B. Volume of blood in ventricles at end-diastole

Question 9

Which of the following is the primary substrate for aerobic metabolism in cardiac tissue?

Answer 9

B. Fatty acids

Question 10

The P wave in an ECG corresponds to:

Answer 10

B. Atrial depolarization

Question 11

Which structure delays impulse transmission to allow atrial contraction before ventricular contraction?

Answer 11

B. AV node

Question 12

What causes a positive chronotropic effect on the heart?

Answer 12

C. Increased Ca2+ influx via beta-adrenergic activation

Question 13

According to Poiseuille’s law, which factor has the greatest impact on blood flow through a vessel?

Answer 13

D. Vessel radius

Question 14

Which of the following best describes the flow of electrical impulses through the heart’s conduction system?

Answer 14

B. SA node → atria → AV node → Bundle of His → Purkinje fibers

Question 15

Which combination correctly pairs autonomic input with its effect on heart rate?

Answer 15

C. Sympathetic → β1 receptor activation → ↑HR

Question 16

Which of the following is responsible for a positive lusitropic effect?

Answer 16

B. Increased Ca²⁺ uptake by the sarcoplasmic reticulum

Question 17

According to Poiseuille’s Law, doubling the radius of a vessel will increase flow by:

Answer 17

C. 8×

Question 18

Which vessel would offer the greatest resistance to flow, assuming all other factors are equal?

Answer 18

B. Arteriole

Question 19

What event occurs immediately after the QRS complex?

Answer 19

B. Semilunar valves open

Question 20

Which wave in an ECG represents ventricular repolarization?

Answer 20

C. T wave

Question 21

The ——– states that wall stress = (radius × pressure) / (2 × wall thickness).

Answer 21

Law of Laplace

Question 22

The ——– is the primary pacemaker of the heart.

Answer 22

SA node

Question 23

——— is calculated as stroke volume (SV) × heart rate (HR).

Answer 23

Cardiac output

Question 24

The ——– is a fetal shunt that bypasses the lungs by connecting the pulmonary artery to the aorta.

Answer 24

Ductus arteriosus

Question 25

--------- in the aortic arch and carotid arteries detect changes in blood pressure and relay signals to the medulla oblongata.

Answer 25

Baroreceptors

Question 26

What type of cardiac hypertrophy does an endurance athlete exhibit?

Answer 26

Eccentric hypertrophy

Question 27

Explain the Frank-Starling mechanism in the context of an athlete's heart.

Answer 27

Increased venous return → ↑ preload → ↑ LV stretch → stronger contraction → ↑ stroke volume.

Question 28

Why is the heart rate low in trained athletes?

Answer 28

High vagal (parasympathetic) tone reduces resting HR

Question 29

What type of cardiac hypertrophy is present in a patient with chronic hypertension?

Answer 29

Concentric hypertrophy

Question 30

How does the Law of Laplace explain changes in hypertensive heart disease?

Answer 30

↑ Afterload (hypertension) → ↑ wall stress → LV thickens to normalize stress

Question 31

Why might a patient with concentric hypertrophy develop heart failure?

Answer 31

Thickened walls reduce compliance → diastolic dysfunction → pulmonary congestion → fatigue

Question 32

Why does a patent ductus arteriosus (PDA) cause cyanosis?

Answer 32

PDA allows deoxygenated blood from pulmonary artery → aorta → systemic circulation (right-to-left shunt)

Question 33

What normally triggers closure of shunts at birth?

Answer 33

↑ Oxygen tension + ↓ prostaglandins → ductus arteriosus constriction; ↑ LA pressure closes foramen ovale

Question 34

How does a patent ductus arteriosus affect ventricular workload?

Answer 34

RV faces ↑ pressure (now pumping to lungs) vs. fetal low-pressure system

Question 35

What is the pathophysiology of cardiac tamponade?

Answer 35

Fluid in pericardial space → ↑ pressure → restricts ventricular filling → ↓ cardiac output

Question 36

Why does jugular venous pressure rise in cardiac tamponade?

Answer 36

Impaired venous return to RA due to compression

Question 37

How would the ECG appear in cardiac tamponade?

Answer 37

Low-voltage QRS complexes ± electrical alternans

Question 38

What arrhythmia is indicated by absent P waves and irregular QRS complexes?

Answer 38

Atrial fibrillation

Question 39

How does atrial fibrillation affect ventricular filling?

Answer 39

Loss of atrial 'kick' → ↓ preload → ↓ stroke volume

Question 40

What electrolyte imbalance could cause atrial fibrillation?

Answer 40

Hypokalemia

Question 41

How does heart mass scale with body mass?

Answer 41

Heart mass ∝ M¹.⁰

Question 42

Why does heart rate scale as M⁻⁰.²⁵?

Answer 42

Smaller animals have higher metabolic rates → need faster circulation

Question 43

How does stroke volume differ between a shrew and an elephant?

Answer 43

Shrew: tiny SV (μL); Elephant: huge SV (liters)

Question 44

Why is blood pressure so high in giraffes?

Answer 44

To overcome gravity for cerebral perfusion

Question 45

How does the left ventricle adapt in giraffes?

Answer 45

Concentric hypertrophy

Question 46

What prevents edema in the legs of giraffes?

Answer 46

Tight skin + valves in leg veins → counteracts hydrostatic pressure