Physiology and Anatomy of the Heart and Blood Vessels

Brachiocephalic trunk

Major artery branching from the aorta.

Superior vena cava

Returns deoxygenated blood from upper body.

Right pulmonary artery

Carries deoxygenated blood to right lung.

Ascending aorta

Major artery carrying oxygenated blood from heart.

Pulmonary trunk

Divides into right and left pulmonary arteries.

Right pulmonary veins

Return oxygenated blood from right lung.

Right atrium

Receives deoxygenated blood from body.

Right coronary artery

Supplies blood to right heart structures.

Anterior cardiac vein

Drains blood from right ventricle.

Right ventricle

Pumps deoxygenated blood to lungs.

Inferior vena cava

Returns deoxygenated blood from lower body.

Left pulmonary artery

Carries deoxygenated blood to left lung.

Left pulmonary veins

Return oxygenated blood from left lung.

Left atrium

Receives oxygenated blood from lungs.

Left coronary artery

Supplies blood to left heart structures.

Left ventricle

Pumps oxygenated blood to the body.

Apex

Bottom tip of the heart.

Intrinsic conduction system

Controls heart rhythm and impulse conduction.

Sinoatrial (SA) node

Heart's pacemaker located in right atrium.

Atrioventricular (AV) node

Delays impulse between atria and ventricles.

Bundle of His

Conducts impulses from AV node to ventricles.

Purkinje fibers

Spread impulses throughout ventricular walls.

Tachycardia

Rapid heart rate over 100 beats per minute.

Bradycardia

Slow heart rate under 60 beats per minute.

Cardiac cycle

One complete heartbeat including contraction and relaxation.

Systole

Phase of heart contraction.

Diastole

Phase of heart relaxation.

Heart sounds

Lub and dup sounds from valve closures.

Tunica intima

Inner layer of blood vessels.

Tunica media

Middle layer with smooth muscle.

Tunica externa

Outermost layer providing vessel protection.

Capillary beds

Networks allowing exchange between blood and tissues.

Microcirculation

Blood flow through capillary beds.

Mitral/Bicuspid Valve

Prevents backflow as blood moves from the left atrium to the left ventricle.

Aortic Semilunar Valve

Prevents backflow as blood exits the left ventricle.

Tricuspid Valve

Prevents backflow as blood moves from the right atrium to the right ventricle

Step 1 of Cardiac Cycle

Blood from the body enters the heart through the Superior Vena Cava and Inferior Vena Cava, carrying deoxygenated blood into the Right Atrium.

Step 2 of Cardiac Cycle

The Right Atrium receives this deoxygenated blood and contracts, pushing the blood through the Tricuspid Valve.

Step 3 of Cardiac Cycle

The Tricuspid Valve opens, allowing blood to flow into the Right Ventricle, then it closes to prevent backflow.

Step 4 of Cardiac Cycle

The Right Ventricle contracts, sending blood upward through the Pulmonary Valve.

Step 5 of Cardiac Cycle

The Pulmonary Valve opens, directing blood into the Pulmonary Trunk, which branches into the Pulmonary Arteries.

Step 6 of Cardiac Cycle

The Pulmonary Arteries transport deoxygenated blood to the lungs, where gas exchange occurs—oxygen enters the blood, and carbon dioxide is removed.

Step 7 of Cardiac Cycle

The now oxygenated blood returns to the heart through the Pulmonary Veins, flowing into the Left Atrium.

Step 8 of Cardiac Cycle

The Left Atrium contracts, pushing blood through the Mitral Valve (Bicuspid Valve).

Step 9 of Cardiac Cycle

The Mitral Valve opens, allowing blood to flow into the Left Ventricle, then closes to prevent backflow.

Step 10 of Cardiac Cycle

The Left Ventricle, the strongest chamber of the heart, contracts powerfully, forcing blood through the Aortic Semilunar Valve.

Step 11 of Cardiac Cycle

The Aortic Semilunar Valve opens, allowing blood to enter the Aorta, the body’s largest artery.

Step 12 of Cardiac Cycle

The Aorta distributes oxygenated blood throughout the body via smaller arteries, supplying oxygen to tissues and organs.