40 Questions
What is the primary function of the heart in the circulatory system?
To establish a pressure gradient for blood delivery
Which side of the heart receives blood from the systemic circulation and pumps it to the pulmonary circulation?
Right side
What is the term for the network of blood vessels that allow for the exchange of oxygen and carbon dioxide between the blood and the lungs?
Capillary network
What is the direction of blood flow in the systemic circulation?
From the heart to the body tissues to the lungs
What is the purpose of the pulmonary circulation?
To pick up oxygen and drop off carbon dioxide from the blood
What is the primary mechanism by which coronary blood flow adjusts to meet cardiac oxygen needs?
Vasodilation
What is the term for the abnormal heart sounds resulting from faulty heart valves?
Heart murmur
During which phase of the cardiac cycle does the heart receive its own blood supply through the coronary circulation?
Diastole
What is the approximate percentage of oxygen extraction at rest in the heart, compared to other tissues?
65% vs. 25%
What is the term for the pathological changes within the coronary artery walls that diminish blood flow?
Coronary artery disease
What is the primary function of autorhythmic cells in the heart?
To initiate and conduct action potentials that promote muscle contraction
What is the role of the sinoatrial node in the cardiac conduction system?
To act as the pacemaker of the heart
What occurs before ventricular contraction begins in the cardiac conduction system?
Atrial excitation and contraction are complete
What is the function of the Purkinje fibers in the cardiac conduction system?
To facilitate the spread of cardiac excitation throughout the ventricular myocardium
What is the purpose of the internodal pathway in the cardiac conduction system?
To facilitate the spread of cardiac excitation from the SA node to the AV node
What is the function of the AV node in the cardiac conduction system?
To delay the impulse briefly to allow complete ventricular filling
During which phase of the cardiac cycle do the atria contract?
Systole
Which of the following valves is closed during ventricular contraction?
Left AV valve
What is the role of the bundle of His in the cardiac conduction system?
To rapidly transmit the impulse to the ventricles
What is the result of Ca++ binding to troponin C (TnC) in the cardiac muscle fiber?
The tropomyosin, troponin I (TnI), and troponin T (TnT) undergo a conformational change
Which heart valve is responsible for preventing backflow from the pulmonary artery to the right ventricle?
Pulmonary valve
What is the function of the chordae tendineae in the heart?
To prevent the eversion of the AV valves
During ventricular contraction, which valve is closed to prevent backflow from the left ventricle to the left atrium?
Mitral valve
Which structure is filled with oxygenated blood when the mitral valve opens?
Left ventricle
What is the function of the fibrous ring that attaches to the heart valves?
To allow the heart to contract more efficiently
Which of the following is NOT a function of the right atrium?
Pumping blood to the systemic circulation
What is the direction of blood flow when the tricuspid valve is open?
From the right atrium to the right ventricle
Which of the following valves is responsible for separating the left ventricle from the aorta?
Aortic valve
What is the function of the papillary muscle in the heart?
To anchor the chordae tendineae
Which structure is responsible for preventing the backflow of blood from the aorta to the left ventricle?
Aortic valve
Which of the following is NOT a characteristic of the left side of the heart compared to the right side?
Larger chamber volume
Which valve is responsible for preventing backflow from the pulmonary artery into the right ventricle?
Pulmonary semilunar valve
What is the primary function of the atria in the heart?
To receive blood from the veins
Which of the following vessels carries oxygen-rich blood from the lungs to the heart?
Pulmonary vein
Which of the following is a characteristic of blood flow through the heart?
Blood flows from veins to atria to ventricles to arteries
What is the role of the spiral arrangement of cardiac muscle bundles around the ventricle?
It enables the 'wringing' of blood from the apex to the base of the ventricle
What type of junctions in the intercalated discs allow for the spread of action potentials between cardiac cells?
Gap junctions
What is the purpose of the pericardial fluid in the pericardial sac?
It minimizes friction during relaxation and contraction
What percentage of cardiac muscle cells are contractile cells?
99%
What is the term for the functional units of cardiac muscle cells connected by intercalated discs?
Syncytia
Learn about the circulatory system, its components, and how it functions. This quiz covers the heart as a dual pump, pulmonary circulation, and more. Test your knowledge of cardiac physiology and the circulatory system.
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