Cardiovascular System and Heart Anatomy

The pulmonary circuit and the systemic circuit.

Carries blood between the heart and lungs for gas exchange.

Carries blood between the heart and the rest of the body.

Deoxygenated blood to the lungs.

Oxygenated blood to the body.

Pulmonary arteries.

Pulmonary veins.

Vena cava, right atrium, tricuspid valve, right ventricle, pulmonary valve, pulmonary arteries, lungs, pulmonary veins, left atrium, mitral valve, left ventricle, aortic valve, aorta.

Receive blood returning to the heart.

Pump blood out of the heart.

Prevents backflow from the right ventricle into the right atrium.

Prevents backflow from the left ventricle into the left atrium.

Backflow from the arteries into the ventricles.

Anchor the AV valves and prevent them from prolapsing.

Tighten the chordae tendineae during ventricular contraction.

The protective sac surrounding the heart.

Connections between cardiac muscle cells that help them contract together.

Electrical signals to pass between cardiac muscle cells.

Autorhythmic cells and contractile cells.

Generate action potentials that initiate the heartbeat.

Generate force to pump blood.

Contractile cells have organized sarcomeres and generate force; pacemaker cells generate electrical signals.

They are striated, branched, usually have one nucleus, connect through intercalated disks, and contain many mitochondria.

The heart's primary pacemaker.

The structure that delays and relays electrical signals to the ventricles.

Allows the atria to finish contracting before the ventricles contract.

SA node, atria, AV node, bundle of His, bundle branches, Purkinje fibers, ventricles.

About 60–100 beats per minute.

About 40–60 beats per minute.

About 20–40 beats per minute.

The electrical signal spreads through the atria and reaches the AV node.

A recording of the heart's electrical activity.

Atrial depolarization.

The atria contract.

Ventricular depolarization.

The ventricles contract.

Ventricular repolarization.

The ventricles relax.

The time for electrical activity to travel from the atria through the AV node toward the ventricles.

The period when the ventricles are depolarized.

Count the number of QRS complexes per minute or use the time between successive R waves.

The contraction phase of the heart.

The relaxation and filling phase of the heart.

The sequence of contraction and relaxation during one heartbeat.

Late diastole, atrial systole, isovolumetric ventricular contraction, ventricular ejection, and isovolumetric ventricular relaxation.

The atria and ventricles are relaxed and the ventricles passively fill with blood.

The atria contract and push remaining blood into the ventricles.

The ventricles contract while all valves are closed, increasing pressure without changing volume.

The semilunar valves open and blood leaves the ventricles.

The ventricles relax while all valves are closed, decreasing pressure without changing volume.

Closure of the AV valves.

Closure of the semilunar valves.

The amount of blood in a ventricle at the end of filling.

The amount of blood remaining in a ventricle after contraction.

The amount of blood pumped out by one ventricle per beat.

SV = EDV - ESV

The volume of blood pumped by one ventricle per minute.

CO = HR * SV

Cardiac output increases.

Cardiac output increases.

The percentage of end-diastolic volume ejected during contraction.

EF = (SV / EDV) *100

The stretch of ventricular muscle before contraction, related to end-diastolic filling.

The pressure or resistance the ventricles must overcome to eject blood.

The ability of cardiac muscle to generate force at a given muscle length.

A substance that increases cardiac contractility.

A substance that decreases cardiac contractility.

Epinephrine, norepinephrine, and digitalis.

The amount of calcium bound to troponin and the number of active cross-bridges.

It increases the force of contraction.

Increased ventricular filling stretches cardiac muscle and produces a stronger contraction.

Stroke volume generally increases as EDV increases.

It increases EDV and usually increases stroke volume.

Venoconstriction, the skeletal muscle pump, and the respiratory pump.

Contracting skeletal muscles squeeze veins and help return blood to the heart.

Pressure changes during breathing help move venous blood toward the heart.

Increases heart rate.

Decreases heart rate.

Parasympathetic activity.

Increases ventricular contractility.

It has its strongest effect on heart rate and has little direct effect on ventricular contractility.

Increases sodium and calcium permeability, speeding pacemaker depolarization.

Increases potassium permeability and decreases calcium permeability, slowing pacemaker depolarization.

Beta-1 adrenergic receptors.

The ongoing autonomic influence that adjusts heart rate; resting heart rate is normally dominated by parasympathetic activity.

Rapid depolarization, initial repolarization, plateau, and repolarization.

Rapid sodium influx.

Sodium channels close and potassium begins leaving the cell.

Calcium influx balanced by potassium leaving the cell.

It creates a long refractory period and prevents sustained tetanic contraction.

Calcium channels close and potassium leaves the cell.

Pacemaker cells spontaneously depolarize and do not have the same stable resting potential or plateau.

Slow inward positive current, including funny sodium current and calcium entry.

Calcium influx.

Potassium efflux.

Exchanges sodium and calcium across the cell membrane.

No, it uses the sodium gradient maintained by the sodium-potassium pump.

It regulates calcium storage in the sarcoplasmic reticulum.

They increase calcium availability and calcium storage in cardiac muscle.

The arterial system.

The venous system.

Carry blood away from the heart and maintain pressure.

Regulate resistance and distribute blood to tissues.

Allow exchange of gases, nutrients, and wastes.

Collect blood from capillaries.

Return blood to the heart and act as a blood-volume reservoir.

The large artery carrying blood from the left ventricle to the systemic circulation.

The large veins that return systemic blood to the right atrium.

Arterioles.

Large arteries.

Capillaries.

The thin layer of cells lining blood vessels.

The formation of new blood vessels.

The volume of blood moving through a vessel or circulation per unit time.

A pressure gradient.

There is no net blood flow.

Pressure difference.

Greater pressure difference produces greater flow if resistance stays constant.

Greater resistance decreases flow if the pressure gradient stays constant.