Heart

This collection of illustrations provides a comprehensive visual exploration of various aspects of heart health and anatomy. Let’s delve into each panel.

Starting with the “Heart Anatomy” panel on the top left, we see a frontal section of the heart showcasing its major chambers and vessels. The heart’s right side features the right atrium and right ventricle, which are involved in pumping deoxygenated blood to the lungs via the pulmonary arteries. Conversely, the left side, composed of the left atrium and ventricle, handles oxygenated blood, pumping it through the aorta to the rest of the body. The superior vena cava, inferior vena cava, and pulmonary veins are also visible, illustrating the pathways through which blood enters and leaves the heart.

The “Heart Intersection” panel to the right provides an anterior view of the heart, focusing on the pathways of blood flow within it. It highlights the aorta, the pulmonary artery, and the superior and inferior vena cava, along with the four main valves: the tricuspid, pulmonary, mitral, and aortic valves. These valves ensure unidirectional blood flow and prevent backflow.

The top right panel, “The pathway of blood flow through the heart,” details the circulatory journey within the heart. Oxygen-depleted blood from the body enters the right atrium, travels to the right ventricle, and is then sent to the lungs via the pulmonary arteries. Once oxygenated, blood returns to the left atrium, moves into the left ventricle, and is finally circulated to the body through the aorta.

Moving to the lower panels, “Aneurysm” depicts the abnormal bulging of a blood vessel in the heart due to weakness in the vessel wall. This can pose a significant risk if the aneurysm ruptures, leading to internal bleeding.

The “Myocardial infarction” panel, often referred to as a heart attack, shows a blockage in a coronary artery which prevents blood from reaching a section of the heart muscle, causing tissue damage or death.

Lastly, the “Heart arrhythmia” panel contrasts a normal heart rhythm with atrial fibrillation. A regular heartbeat is depicted alongside an electrocardiogram (ECG) tracing, while atrial fibrillation is characterized by an irregular and often rapid heart rate, which is also reflected in its distinct ECG pattern.

These visual aids are integral in understanding heart function, the impact of various cardiac conditions, and the importance of cardiovascular health.

The illustration before us explicates the functions of the heart valves during two critical phases of the cardiac cycle: diastole and systole.

In the left panel, representing diastole, we observe that the heart muscles are relaxed, allowing the chambers to fill with blood. The tricuspid and bicuspid (mitral) valves are open, facilitating the flow of blood from the atria to the ventricles. Concurrently, the pulmonary and aortic valves are closed to prevent the backflow of blood from the pulmonary artery and aorta into the ventricles.

The right panel illustrates systole, where the heart muscles contract. This contraction propels blood out of the heart: from the right ventricle into the pulmonary artery through the open pulmonary valve, and from the left ventricle into the aorta through the open aortic valve. Simultaneously, the tricuspid and bicuspid valves are closed to prevent blood from flowing back into the atria.

The bottom part of the image provides a superior view of the heart’s internal structure during both diastole and systole, further illustrating the open or closed states of the valves. During diastole, the atrioventricular valves (tricuspid and bicuspid) are open, while the semilunar valves (pulmonary and aortic) are closed. This reverses during systole, ensuring that blood moves efficiently through the heart and into the systemic and pulmonary circulations, a process vital to maintaining life-sustaining blood flow throughout the body.

This illustration provides a posterior view of the heart, highlighting its external anatomy and the flow of blood through its various vessels.

At the top, the aorta, the main artery of the body, is shown branching out from the heart. This artery distributes oxygenated blood to all parts of the body. Adjacent to the aorta are the left and right pulmonary arteries, colored in blue, which carry deoxygenated blood from the right ventricle to the lungs for oxygenation.

The superior vena cava and inferior vena cava are indicated in blue as well, signifying their role in carrying deoxygenated blood from the body back to the heart, emptying into the right atrium.

The right side of the heart is comprised of the right atrium and right ventricle. The right atrium receives deoxygenated blood from the body, while the right ventricle pumps this blood to the lungs through the pulmonary artery.

On the left side, the left atrium and left ventricle are visible. The left atrium receives oxygen-rich blood from the lungs via the left pulmonary veins, which is then delivered to the left ventricle. From there, the left ventricle pumps oxygenated blood into the aorta for systemic circulation.

Additionally, the network of yellow pathways depicts the coronary arteries and veins, which are responsible for supplying the heart muscle itself with the necessary oxygen and nutrients to function effectively.

This diagram presents a cross-sectional view of the heart, detailing the flow of blood and the structure of its chambers and valves.

At the top, we see the ascending aorta, which carries oxygenated blood from the left ventricle to the head and arms. Branching from the ascending aorta is the pulmonary artery, shown in blue, indicating that it transports deoxygenated blood; it bifurcates to supply both lungs.

The superior vena cava is shown returning deoxygenated blood from the head and arms to the right atrium, while the inferior vena cava carries deoxygenated blood from the lower body to the same chamber. These vessels are part of the systemic circulation returning blood to the heart after oxygen has been delivered to the body’s tissues.

The right pulmonary veins, connected to the right lung, and the left pulmonary veins, connected to the left lung, are shown in red, signifying they are carrying oxygenated blood from the lungs back to the left atrium.

Within the heart, we observe the right atrium and ventricle, and the left atrium and ventricle. The tricuspid valve is positioned between the right atrium and ventricle, ensuring one-way flow of blood into the right ventricle. The mitral or bicuspid valve performs a similar function between the left atrium and ventricle.

The pulmonary semilunar valve, situated at the junction of the right ventricle and pulmonary artery, prevents backflow of blood into the ventricle. On the left side, the aortic semilunar valve, located between the left ventricle and the aorta, serves the same purpose, ensuring efficient flow into systemic circulation.

The descending aorta is depicted at the bottom, extending from the aortic arch to distribute blood to the lower body.

This illustration is key in understanding how the heart functions as a pump, moving blood through pulmonary and systemic circuits, and the role of valves in maintaining the directionality of blood flow.

The image illustrates the correlation between an electrocardiogram (ECG) tracing and the electrical activity of the myocardium during one cardiac cycle.

The ECG tracing at the top represents the electrical events that occur during a heartbeat. Each part of the ECG corresponds to a specific electrical event in the heart:

  1. The initial upward deflection, or P wave, corresponds to atrial depolarization, which is the electrical activation that leads to atrial contraction.
  2. Following a short flat line, atrial repolarization occurs but is typically not visible on the ECG as it is masked by the subsequent, larger ventricular depolarization.
  3. The QRS complex, a rapid series of deflections, reflects ventricular depolarization, the electrical event that triggers ventricular contraction. Notably, the atria repolarize during this phase, but this is obscured by the dominant activity of the ventricles.
  4. The segment following the QRS complex is the ST segment, which indicates the beginning of the ventricles’ repolarization, which is essential for the muscles to relax.
  5. The T wave is the upward deflection after the ST segment, showing ventricular repolarization completion.
  6. Finally, the ECG line returns to baseline, indicating the heart’s electrical reset in preparation for the next beat.

Below the ECG tracing are six heart diagrams depicting various stages of electrical activity:

  1. Atrial depolarization begins, initiating the P wave on the ECG and causing the atria to contract.
  2. Atrial depolarization is complete, paving the way for the electrical impulse to travel to the ventricles.
  3. Ventricular depolarization begins at the apex of the heart, creating the QRS complex on the ECG. This electrical activity leads to ventricular contraction.
  4. Ventricular depolarization is complete, and the ventricles are fully contracted.
  5. Ventricular repolarization begins, represented by the ST segment on the ECG, leading to the start of ventricular relaxation.
  6. Ventricular repolarization is complete, reflected by the T wave on the ECG, allowing the ventricles to finish relaxing.

This synchronized dance between electrical signals and mechanical action enables the heart to pump blood efficiently, with each beat triggered by these intricate electrical impulses.

TermDefinition
AneurysmAbnormal bulging of a blood vessel in the heart due to weakness in the vessel wall, posing a risk of rupture and internal bleeding.
AortaThe main artery of the body that distributes oxygenated blood to all parts of the body from the left ventricle.
Aortic ValveA valve between the left ventricle and the aorta that prevents backflow of blood into the left ventricle.
Atrial DepolarizationThe electrical activation that leads to atrial contraction, represented by the P wave on an electrocardiogram (ECG).
Atrial FibrillationA heart arrhythmia characterized by an irregular and often rapid heart rate, reflected in a distinct ECG pattern.
AtriumUpper chambers of the heart; the right atrium receives deoxygenated blood from the body, and the left atrium receives oxygenated blood from the lungs.
Bicuspid ValveAlso known as the mitral valve; it allows blood flow from the left atrium to the left ventricle and prevents backflow.
Coronary ArteryArteries that supply blood to the heart muscle itself.
DiastolePhase of the cardiac cycle when the heart muscles relax and the chambers fill with blood; the tricuspid and bicuspid (mitral) valves are open, while the pulmonary and aortic valves are closed.
ECGElectrocardiogram, a tracing representing the electrical events during a heartbeat.
Inferior Vena CavaA large vein carrying deoxygenated blood from the lower body back to the right atrium of the heart.
Left VentricleA chamber of the heart that pumps oxygenated blood into the aorta for systemic circulation.
Mitral ValveA valve that allows blood flow from the left atrium to the left ventricle and prevents backflow, also known as the bicuspid valve.
Myocardial InfarctionOften referred to as a heart attack; occurs when a blockage in a coronary artery prevents blood from reaching a section of the heart muscle, causing tissue damage or death.
Pulmonary ArteryThe artery carrying deoxygenated blood from the right ventricle to the lungs for oxygenation.
Pulmonary ValveA valve located between the right ventricle and the pulmonary artery that prevents backflow of blood into the right ventricle.
Pulmonary VeinsVeins that carry oxygenated blood from the lungs back to the left atrium of the heart.
Right VentricleA chamber of the heart that pumps deoxygenated blood to the lungs through the pulmonary artery.
Superior Vena CavaA large vein carrying deoxygenated blood from the head, neck, and upper limbs back to the right atrium of the heart.
SystolePhase of the cardiac cycle when the heart muscles contract, propelling blood out of the heart; the tricuspid and bicuspid valves are closed to prevent backflow into the atria, while the pulmonary and aortic valves are open.
Tricuspid ValveA valve that allows blood flow from the right atrium to the right ventricle and prevents backflow.
Ventricular DepolarizationThe electrical event that triggers ventricular contraction, represented by the QRS complex on an ECG.
Ventricular RepolarizationThe process allowing the ventricles to relax, represented by the T wave on an ECG.

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