33 Questions
Where is the heart located in the body?
In a space called the mediastinum
Which chamber of the heart collects blood and pushes it into the lower chambers?
Left atrium
Which vessel connects the right ventricle to the pulmonary trunk?
Pulmonary artery
What is the only artery that carries deoxygenated blood in the body?
Pulmonary artery
Which layer of the heart is described as the middle thickest layer containing muscle cells, nerve fibers, and blood vessels?
Myocardium
What is the function of auricles in the heart?
Empty blood into atria
What happens at 0mV in the heart muscle?
Ca++ channels close and K+ channels open for repolarization
What role does Ca++ play during the contraction of heart muscle?
Binds to troponin to allow cross bridge formation between myosin and actin
Which component of the heart's conduction system would have the highest intrinsic firing rate?
SA node
What is the purpose of electrodes placed on the body during an ECG?
To record electrical signals of the heart
What is another name for an electrocardiogram?
ECG
What is the main purpose of AED's?
Correcting fibrillations
During which phase of the cardiac cycle are the semilunar valves closed?
Diastole
What happens during ventricular diastole?
Relaxation and closure of semilunar valves
Which wave represents repolarization of the ventricles?
T wave
What is the amount of blood normally pushed out by the ventricles as stroke volume?
$70 - 80$ mL
In which phase does the atria contract following depolarization, known as 'atrial kick'?
Atrial systole
What causes the sound known as S3 in a healthy heart?
Blood flowing into the atria
Which term is used to refer to having both S3 and S4 heart sounds?
S7
What is the formula for calculating Cardiac Output (CO)?
CO = HR * SV
What is considered the normal range for Cardiac Output (CO) in liters per minute?
4 - 8 L/min
What is the target heart rate range meant to achieve?
Maintaining High Cardiac Output
How is Ejection Fraction calculated?
(SV / EDV) * 100
Which layer of the heart is responsible for releasing endothelins, strong vasoconstrictors?
Endocardium
How many septa are present in the heart?
3
Which structure in the heart was a foramen ovale in a fetus?
Fossa ovalis
What is the function of the moderator band in the right ventricle?
Conduct impulses for cardiac conduction
Which chamber of the heart receives oxygenated blood from the pulmonary veins?
Left atrium
What is the main function of heart valves?
Ensure unidirectional blood flow
Where do arteries branch off to supply blood to the myocardium and other components?
Aorta
What is the function of Purkinje fibers in the heart?
Conduct impulses around the ventricles
What is the total time from initial impulse to ventricle depolarization in the heart?
225 ms
Which type of cells in the heart exhibit autorhythmicity and can initiate an electrical potential at a fixed rate?
Myocardial conducting cells
This quiz covers the cardiac conduction system and action potentials in the heart, including the role of calcium ions, refractory periods, and different firing rates of nodes in the heart. Test your knowledge on how ion channels open and close during repolarization, and the mechanisms behind muscle contraction in the heart.
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