Cardiovascular System Overview

The circulation that delivers oxygenated blood from the heart to the body and returns deoxygenated blood back to the heart.

The circulation that carries deoxygenated blood from the heart to the lungs for oxygenation and returns oxygenated blood back to the heart.

The system of blood vessels that supplies blood to the heart muscle itself.

The amount of blood pumped by the heart per minute.

The increase in heart rate and stroke volume during exercise, leading to increased cardiac output.

A decrease in stroke volume during prolonged exercise, while heart rate increases to maintain cardiac output.

The redirection of blood flow during exercise, where blood flow to muscles increases and blood flow to other organs decreases.

The heart acts as a double pump because it has two separate circuits: the systemic circulation and the pulmonary circulation.

The P wave on an electrocardiogram represents the electrical impulse generated by the SA node, spreading through both atria, causing them to contract.

The QRS complex represents the electrical activity during ventricular contraction, as the signal travels through the Purkinje fibers.

The T wave on an ECG represents the electrical activity associated with the repolarization of the ventricles, as they relax and prepare for the next contraction.

Red blood cells are responsible for carrying oxygen from the lungs to the body's tissues and carbon dioxide back to the lungs for exhalation.

The skeletal muscle pump helps return blood to the heart by squeezing veins when muscles contract, increasing pressure and pushing blood upward.

The thoracic pump assists venous return by creating a pressure difference between the chest and abdominal cavities during breathing, pushing blood upwards.

Venoconstriction, triggered by the nervous system during exercise, helps increase venous return by narrowing veins and pushing blood towards the heart.

The Frank-Starling law states that the stronger the myocardial stretch during diastole (preload), the more forceful the subsequent ventricular contraction.

The heart muscle tissue responsible for contraction and blood pumping. It's involuntary, striated, and activated by calcium and the sliding filament theory.

A heart attack occurs when blood flow to the myocardium is blocked, causing tissue damage and death due to lack of oxygen. It's often caused by fatty plaque buildup in the coronary arteries, leading to a clot that blocks blood flow.

The flow of blood through the heart, starting with the deoxygenated blood entering the right atrium, then pumps to the right ventricle to the lungs for oxygenation. The oxygenated blood returns to the left atrium, then pumps to the left ventricle, and finally to the systemic circulation.

Valves in the heart ensure one-directional blood flow. AV valves (tricuspid & bicuspid) prevent backflow between atria and ventricles during ventricular contraction. Semilunar valves (pulmonary & aortic) close when blood is pumped out during ventricular relaxation. Leaky valves cause murmurs.

Refers to the contraction phase of the heart muscle, when the ventricles pump blood into the pulmonary arteries and aorta. It's regulated by the SA node and lasts for about 0.3 seconds. During this phase, the semilunar valves close.

Refers to the relaxation phase of the heart muscle, when the ventricles fill with blood from the atria. It's regulated by the AV node and lasts for about 0.5 seconds. During this phase, the AV valves close.

The electrical activity of the heart originates in the sinoatrial (SA) node, which acts as the pacemaker. The signal travels through the atria, causing them to contract. The signal then reaches the atrioventricular (AV) node, where it's briefly delayed before moving to the ventricles via the Bundle of His and Purkinje fibers, causing ventricular contraction.

The force of blood pushing against the walls of the arteries when the heart contracts (systole) is called systolic blood pressure. The pressure when the heart is at rest (diastole) is called diastolic blood pressure.

The volume of blood in the left ventricle at the end of diastole (relaxation phase). It indicates how much blood is available to be pumped out with each heartbeat.

The percentage of blood pumped out of the left ventricle with each heartbeat. It measures the heart's efficiency in ejecting blood.

During exercise, the body prioritizes blood flow to working muscles, reducing blood flow to other organs like the stomach and kidneys. This ensures that the muscles receive adequate oxygen and nutrients for increased activity.

Training increases the heart's size and strength, improving its ability to pump blood. This leads to a larger stroke volume, meaning more blood is pumped with each beat, and a lower resting heart rate.

Increased blood volume, especially in the red blood cells, is a positive adaptation to training. This allows for better oxygen transport throughout the body.