Cardiac Anatomy
The human heart is approximately the size of this object
Deoxygenated blood returning from the body enters the heart through these two main vessels
What are the superior and inferior vena cava?
Known as the normal pacemaker of the heart because it fires fastest and maintains control
What is the sinus node (SA node)
On EKG graph paper, the width of one small block represents this amount of time in seconds
What is 0.04 seconds?
A cardiac beat that fires after a pause longer than the normal R-R interval
What is an escape beat?
This outermost layer of the heart is where the coronary arteries like
Blood passes through this valve when flowing from the right atrium into the right ventricle
What is the tricuspid valve?
The standard pacemaker firing rate of the sinus node in beats per minute
What is 60–100 bpm
On EKG graph paper, the width of one big block represents this amount of time in seconds
What is 0.20 seconds?
During this specific refractory period, a cardiac cell cannot respond to another impulse no matter how strong
What is the absolute refractory period?
This band of tissue separates the right and left ventricles
What is the Intraventricular Septum?
This structure carries deoxygenated blood from the right ventricle to the lungs, making it the only artery in the body carrying deoxygenated blood
What is the pulmonary artery?
The inherent firing rate range of the AV junction pacemaker cell
What is 40–60 bpm
The general term for measurements of time between EKG waves and complexes
What are intervals?
During this period, a cardiac cell will respond only if the incoming impulse is very strong
What is the relative refractory period?
The phase during diastole where the atria contract to squeeze the remaining blood into the ventricles
What is the atrial kick?
Oxygenated blood coming from the left atrium enters the left ventricle by passing through this valve
What is the mitral valve
The electrical conduction pathway sequence proceeds from the SA node through interatrial/internodal tracts to the AV node, down the Bundle of His and bundle branches, ending at these structures
What are the Purkinje fibers?
The normal duration range for a PR interval in seconds
What is 0.12 to 0.20 seconds?
In this "hyper" period, a cardiac cell can respond even to a very weak impulse
What is the supernormal period?
The names of the four chambers of the heart
Right atrium, Right ventricles, Left atrium, Left ventricles
The largest artery leaving the left ventricle that delivers oxygenated blood to the rest of the body
What is the aorta
Impulse conduction travels from the AV node directly to this bundle before dividing into the left and right branches
What is the Bundle of His?
The PR interval measures the time required for an impulse to travel between these two heart structures
What are the atrium and ventricle?
Discharge of electricity - Occurs when cardiac cell becomes positively charged.
What is Depolarization?