37 Questions
Where is the base of the heart located?
Superior and medial to the apex
Which chamber of the heart collects blood and pushes it into the lower chambers?
Left atrium
Where does CO2 leave and O2 enter in the heart?
Pulmonary capillaries
Which artery is the only one to carry deoxygenated blood?
Pulmonary artery
What is the function of auricles in the heart?
Collect blood and empty into atria
Which layer of the heart is the middle thickest layer consisting of muscle cells, nerve fibers, and blood vessels?
Myocardium
During the cardiac cycle, which phase is characterized by the pumping of blood into circulation?
Systole
What is the function of an artificial pacemaker in the heart?
Correcting fibrillations
Which component of the ECG represents the repolarization of ventricles?
T wave
What is the primary function of an AED (Automated External Defibrillator) in cardiac emergencies?
Correcting fibrillations
Which phase of the cardiac cycle marks the relaxation of the ventricles and closing of semilunar valves?
Ventricular diastole
What term is used to describe the amount of blood pushed out by the ventricles during each contraction?
Stroke volume
What happens at 0mV in the heart?
Ca++ channels close and K+ channels open for typical repolarization
What is the main purpose of the long refractory period in the heart?
To prevent premature contractions
Which node would fire 80-100 times per minute if not for endocrine control?
SA node
What is the abbreviation for 'Electrocardiogram'?
ECG
What do electrodes placed on the body during an ECG record?
Electrical signals of the heart
Which layer of the heart is responsible for releasing endothelins, strong vasoconstrictors?
Endocardium
What is the function of the atrioventricular valves?
Opening during ventricular contraction
What structure divides the heart into chambers and is a physical extension of the myocardium?
Septum
Which event causes the 'lub' sound in a heartbeat?
Closing of atrioventricular valves
Which valve separates the left atrium from the left ventricle?
Mitral valve
What does an ejection fraction measure?
Percentage of blood pumped out of the ventricles
What term describes the blood vessel interconnections that allow blood to flow even if there is a partial blockage?
Anastomosis
How does exercise affect stroke volume?
Increases it
Which cells in the heart conduct impulses and contract to pump blood through the body?
Myocardial conducting cells
What is the function of the vagus nerve in heart rate regulation?
Slows heart rate
What structure in the heart sets the normal cardiac rhythm and is known as the pacemaker?
Sinoatrial (SA) node
Which factor can decrease heart rate?
Hypoxia (lack of O2)
What is the total time from initial impulse to ventricle depolarization in the heart?
~225 ms
What happens when there is less filling time in the heart?
Decreased end-diastolic volume
Which ions are responsible for creating the spontaneous depolarization in cardiac conductive cells?
$Na^+$ and $Ca^{2+}$
When do the 4 chambers of the heart complete their development?
End of week 5
What happens during the plateau phase of cardiac contractile cells?
$Ca^{2+}$ channels close
What causes a heart murmur?
Turbulent blood flow
What do gap junctions in cardiac muscle cells allow for?
$ion$ movement
What is the function of S2 in a heartbeat?
Opening of semilunar valves
Test your knowledge about the electrical conduction system of the heart. Learn about the role of calcium ions, refractory periods, and the firing rates of different nodes. Understand how different channels open and close to regulate heart contractions.
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