Cardiovascular System Overview

<p>Ventricles are the lower chambers of the heart. (D)</p> Signup and view all the answers

<p>Aortic valve (C)</p> Signup and view all the answers

<p>Slow influx of Ca++ (B)</p> Signup and view all the answers

<p>-90 mV (A)</p> Signup and view all the answers

<p>Tricuspid and mitral valves (D)</p> Signup and view all the answers

<p>Blood is forced into blood vessels through semilunar valves (A)</p> Signup and view all the answers

<p>Via gap junctions in intercalated discs (A)</p> Signup and view all the answers

<p>To generate the electrical impulse for contraction (B)</p> Signup and view all the answers

<p>Conductivity (C)</p> Signup and view all the answers

<p>Phase 0: rapid depolarization (A)</p> Signup and view all the answers

<p>-90 mV (B)</p> Signup and view all the answers

<p>The impulse is generally delayed (A)</p> Signup and view all the answers

<p>Purkinje fibers (D)</p> Signup and view all the answers

<p>-40 mV (A)</p> Signup and view all the answers

<p>SA node → AV node → bundle of His → Purkinje fibers (B)</p> Signup and view all the answers

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The heart is composed of four chambers: two upper atria and two lower ventricles. The atria receive blood and pump it to the ventricles, while the ventricles pump blood out of the heart.

The heart valves are like one-way doors, ensuring blood flows in the right direction. They open and close based on pressure changes during heart contractions.

The pulmonary circuit is the pathway between the heart and lungs, where blood picks up oxygen and releases carbon dioxide.

The systemic circuit carries oxygen-rich blood from the heart to the body and returns deoxygenated blood back to the heart.

The coronary circuit supplies blood to the heart muscle itself, providing oxygen and nutrients for its own function.

The ability of pacemaker cells to generate an electrical impulse without external stimulation.

The ability of pacemaker cells to pass the electrical impulse to the next cell in the conduction system.

The ability of heart muscle cells to shorten in response to an electrical impulse, leading to contraction.

The primary pacemaker of the heart, generating impulses between 60 and 100 times per minute.

Located low in the right atrium, it slows down the impulse conduction between the atria and ventricles, ensuring coordinated contraction.

Found in the interventricular septum, it divides into right and left branches, carrying the electrical impulse from the AV node to the ventricles.

Located within the apex of the heart, these fibers spread throughout the ventricles, causing their powerful contraction.

The normal sequence of events that initiate and transmit electrical impulses through the heart: SA node-AV node-Bundle of His-Purkinje fibers.

The phase of the cardiac action potential where sodium channels close and potassium channels open, leading to a rapid decrease in membrane potential.

The initial phase of the cardiac action potential, characterized by a rapid influx of sodium ions into the cell. This causes the membrane potential to become more positive.

The plateau phase of the cardiac action potential is characterized by a slower influx of calcium ions, prolonging the depolarized state. This is crucial for muscle contraction.

The period in the cardiac cycle where the heart chambers relax and fill with blood.

The period in the cardiac cycle when the heart chambers contract and pump blood out.