35 Questions
What happens at 0mV in terms of ion channels during repolarization of the heart?
Ca++ channels close and K+ channels open
What is the function of Ca++ ions binding to troponin during muscle contraction?
Ca++ ions allow the myosin and actin cross bridge formation
If the SA node is not under endocrine control, how many times would it fire per minute?
Between 80 - 100 times
What is the purpose of an Electrocardiogram (ECG or EKG)?
To record electrical signals of the heart
Which part of the heart has the lowest firing rate recorded?
Purkinje fibers
What is the primary function of the P wave in the cardiac cycle?
Depolarization of the atria
Which phase occurs when the semilunar valves are closed and blood flows into the atria and through into the ventricles?
Atrial diastole
What is the primary function of an artificial pacemaker in cardiac muscle metabolism?
Ensuring effective heart contractions
During ventricular diastole, what happens to the semilunar valves?
They close as relaxation phase begins
Which phase in the cardiac cycle involves an increase in pressure that forces the semilunar valves to open?
Ventricular systole
What is the main purpose of the QRS complex in the cardiac cycle?
Depolarization of ventricles and masking repolarization of atria
Where is the heart located in the body?
Between the lungs in the mediastinum
What is the function of the ventricles in the heart?
Pump blood out to the body or lungs
Which chamber of the heart connects to the pulmonary trunk?
Right ventricle
What is the purpose of the auricles in the heart?
Hold blood and empty into atria
Which blood vessel is the only artery to carry deoxygenated blood?
Pulmonary artery
What is the middle thickest layer of the heart that contains muscle cells, nerve fibers, and blood vessels?
Myocardium
What are the audible sounds of a healthy heart?
S1 and S2
Which condition is referred to as S7?
Having both S3 and S4
What is the formula for calculating Cardiac Output (CO)?
CO = SV * HR
What is considered a normal range for Cardiac Output (CO) in liters per minute?
4 - 8 L/min
What is the percentage range for a normal Ejection Fraction?
50% - 70%
Where does nervous control of Heart Rate come from?
Medulla oblongata
Which stimulation dominates the autonomic tone of the heart?
Vagal stimulation
What happens to Stroke Volume (SV) if there is less filling time?
Decreases SV
'Cardiac reserve' refers to:
The difference between max CO and resting CO
What increases the ventricular stretch leading to more powerful contraction of sarcomeres?
Increased filling time
Which layer of the heart is described as the innermost layer that lines the chambers and covers heart valves?
Endocardium
What cells release endothelins, strong vasoconstrictors that may regulate growth patterns of cardiac muscle cells?
Endothelial cells
Which structure in the heart divides it into chambers and is described as physical extensions of the myocardium?
Septum
What is the function of the moderator band in the right ventricle of the heart?
To conduct cardiac impulses
Which valve disorder is usually caused by inflammation?
Endocarditis
What is the function of coronary arteries in the heart?
Bring oxygenated blood to the myocardium
What is the role of gap junctions in cardiac muscle cells?
Allow ions to travel between cells for proper contractile rhythm
Where is the Sinoatrial (SA) node located in the heart, and what is its function?
In the right atrium, sets normal cardiac rhythm
Test your knowledge of the cardiac conduction system and electrocardiogram with this quiz! Learn about the different phases of the action potential in the heart, including depolarization, repolarization, and refractory periods. Explore the roles of calcium ions, potassium channels, and the SA node in regulating heart contractions.
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