35 Questions
What is the function of the atria in the heart?
Collect blood and push it into lower chambers
Which vein carries deoxygenated blood?
Pulmonary vein
Where is the heart located within the body?
In a space called the mediastinum
Which layer of the heart produces lubricating fluid?
Epicardium
What is the purpose of the fat-filled grooves called sulci in the heart?
Contain coronary blood vessels
Which chamber of the heart pumps blood out to the body or lungs?
Left ventricle
What happens at 0mV during repolarization?
K+ channels close
Which ion is responsible for the plateau phase in cardiac action potentials?
Ca++
What is the firing rate of the SA node without endocrine control?
80 - 100 times per minute
Which part of the heart's conduction system has the slowest firing rate?
Purkinje fibers
What is the purpose of using electrodes on the body during an ECG?
To record electrical signals of the heart
During which phase of the cardiac cycle do the atria contract following depolarization?
Atrial systole
What is the main function of an artificial pacemaker in the context of cardiac muscle activity?
Delivers electrical impulses for effective heart contractions
What happens to the pressure in the heart during ventricular systole?
Increases to force semilunar valves open
Which component of the ECG represents the repolarization of the ventricles?
T wave
What is the significance of myoglobin in heart muscle cells?
Storing oxygen
Which phase of the cardiac cycle marks the relaxation of both the ventricles and atria?
Ventricular diastole
Which heart sound is associated with the closing of semilunar valves?
S2
What does S4 indicate in terms of blood flow in the heart?
Blood flowing into a stiff or hypertrophic ventricle
In cardiac physiology, what is the formula for Cardiac Output (CO)?
CO = HR * SV
What percentage range is considered normal for the ejection fraction of the heart?
50% - 70%
What can increase Cardiac Output by 4-8 times?
Activity
Where does nervous control of heart rate primarily originate from?
Medulla oblongata
Which neurotransmitter slows down the rate of depolarization in the heart?
Acetylcholine
What increases heart rate and often accompanies a surge in cortisol?
Stress and anxiety
What is the function of endothelins released by the endothelium?
Act as vasoconstrictors
Where is the fossa ovalis located?
Interatrial septum
What is the function of the moderator band in the heart?
Muscle for cardiac conduction
What happens during the plateau phase in cardiac contractile cells?
Na+ channels close, Ca++ channels are open, and few K+ channels are open
Why do cardiac muscle cells have a long refractory period?
To prevent tetany
Where is the sinoatrial (SA) node located?
Superior and posterior wall of the right atrium
What is the main function of the atrioventricular (AV) node?
Sets normal cardiac rhythm
What is the purpose of bundle of His in the heart's conduction system?
Receives impulse from AV node and branches into right and left bundle branches
Why do semilunar valves make an audible sound as they close?
They have no muscular attachments
What is the role of desmosomes in cardiac muscle cells?
Stop cardiac muscle cells from ripping apart
Test your knowledge on the basic concepts of cardiac physiology including action potential, refractory periods, ion channels, and conduction pathways in the heart.
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