Layers of the Heart
This innermost layer of the heart lines the chambers and covers the heart valves.
What is Endocardium?
Valve between the right atrium and right ventricle
What is triscuspid valve?
During this phase of the cardiac cycle, ventricular contraction compresses the coronary vessels.
What is systole?
Located in the right atrial wall, this structure serves as the heart’s natural pacemaker and normally generates impulses at 60–100 beats/min.
What is the sinoatrial (SA) node?
This conduction pathway carries electrical impulses from the Bundle of His to the right ventricle.
What is the right bundle branch?
This middle layer of the heart is made of involuntary striated cardiac muscle and is responsible for heart contraction and pumping action.
What is Myocardium?
Valve between the right ventricle and pulmonary arteries
What is pulmonary valve?
The primary phase of coronary perfusion
What is diastole?
A phase in which the heart resets itself after contracting, preparing for another cycle of depolarization and contraction (the next heartbeat).
What is repolarization?
This network spreads electrical impulses throughout the ventricles, causing ventricular depolarization and contraction, with an intrinsic firing rate of 20–40 beats/min.
What are the Purkinje fibers?
This outer layer of the heart is a connective tissue layer associated with the pericardium.
What is the epicardium?
This valve is located between the left ventricle and the aorta and prevents blood from flowing back into the left ventricle.
What is aortic valve?
Coronary blood flow occurs primarily during this phase of the cardiac cycle.
What is ventricular diastole?
This structure is the only normal electrical connection between the atria and ventricles. Located near the bundle of His, it helps transmit electrical impulses and can provide a backup pacemaker at 40–60 beats/min.
What is the atrioventricular (AV) node?
This conduction pathway carries electrical impulses from the Bundle of His to the left ventricle.
What is the left bundle branch?
A two-layered outer sac surrounding the heart that contains fluid to reduce friction during heart movement.
What is pericardium?
Structures that support the valve leaflets and help prevent backward blood flow (regurgitation)?
What is chordae tendinaea?
Specialized filaments that support the valve leaflets and help prevent blood from flowing backward (regurgitation).
What is Chordae Tendineae?
A process in which heart muscle cells become electrically activated, leading to muscle contraction and allowing the heart to pump blood.
What is depolarization?
This structure receives impulses from the AV node, travels through the interventricular septum, and conducts electrical impulses toward the right and left bundle branches.
What is the Bundle of His?
These fibrous cords support the valve leaflets and help prevent blood from flowing backward into the atria during ventricular contraction.
What are the chordae tendineae?
This valve is located between the left atrium and left ventricle and prevents blood from flowing back into the left atrium.
What is biscuspid (mitral) valve?
These two major coronary arteries originate from the aorta and supply blood to the heart muscle.
What is the right and left coronary arteries?
A phase of no electrical activity that is represented by the isoelectric line on an EKG and occurs when the heart muscle is not actively depolarizing or repolarizing.
What is the resting phase?
These pathways are located within the atrial walls and conduct electrical impulses from the SA node to the AV node.
What are the internodal pathways?