Chambers of the Heart

The heart has four main chambers that work together to circulate blood throughout the body. Understanding these chambers is crucial in Honors Anatomy and Physiology, as they play key roles in oxygen delivery and overall cardiovascular function.

1. Right atrium

   • Receives deoxygenated blood from the body via the superior and inferior vena cavae.
   • Contains the sinoatrial (SA) node, which initiates the heartbeat.
   • Blood flows through the tricuspid valve into the right ventricle.

2. Left atrium

   • Receives oxygenated blood from the lungs through the pulmonary veins.
   • Has a thicker wall than the right atrium to handle higher pressure.
   • Blood flows through the mitral valve into the left ventricle.

3. Right ventricle

   • Pumps deoxygenated blood to the lungs via the pulmonary artery.
   • Has a thinner wall compared to the left ventricle due to lower pressure requirements.
   • Contains the pulmonary valve, which prevents backflow into the right atrium.

4. Left ventricle

   • Pumps oxygenated blood to the entire body through the aorta.
   • Has the thickest wall of all chambers to generate high pressure.
   • Contains the aortic valve, which prevents backflow into the left atrium.

5. Septum (interatrial and interventricular)

   • Interatrial septum separates the right and left atria.
   • Interventricular septum separates the right and left ventricles.
   • Prevents mixing of oxygenated and deoxygenated blood.

6. Valves (tricuspid, mitral, pulmonary, and aortic)

   • Tricuspid valve: located between the right atrium and right ventricle; prevents backflow during ventricular contraction.
   • Mitral valve: located between the left atrium and left ventricle; ensures one-way blood flow.
   • Pulmonary valve: located between the right ventricle and pulmonary artery; prevents backflow into the ventricle.
   • Aortic valve: located between the left ventricle and aorta; prevents backflow into the ventricle.

7. Blood flow through the chambers

   • Blood enters the right atrium from the body, moves to the right ventricle, then to the lungs.
   • Oxygenated blood returns to the left atrium, flows into the left ventricle, and is pumped to the body.
   • The cycle is continuous, ensuring efficient circulation.

8. Differences in wall thickness between chambers

   • Right atrium and ventricle have thinner walls due to lower pressure requirements.
   • Left atrium has a thicker wall than the right atrium, but not as thick as the left ventricle.
   • Left ventricle has the thickest wall to withstand high pressure when pumping blood to the body.

9. Function of each chamber

   • Right atrium: collects deoxygenated blood from the body.
   • Left atrium: collects oxygenated blood from the lungs.
   • Right ventricle: pumps deoxygenated blood to the lungs for oxygenation.
   • Left ventricle: pumps oxygenated blood to the entire body.

10. Location of major blood vessels entering and exiting each chamber

    • Right atrium: receives blood from the superior and inferior vena cavae; sends blood to the right ventricle via the tricuspid valve.
    • Left atrium: receives blood from the pulmonary veins; sends blood to the left ventricle via the mitral valve.
    • Right ventricle: receives blood from the right atrium; sends blood to the pulmonary artery via the pulmonary valve.
    • Left ventricle: receives blood from the left atrium; sends blood to the aorta via the aortic valve.