Blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs. Blood leaves the heart through the aortic valve, into the aorta and to the body. This pattern is repeated, causing blood to flow continuously to the heart, lungs and body.

The major blood vessels connected to your heart are the aorta, the superior vena cava, the inferior vena cava, the pulmonary artery (which takes oxygen-poor blood from the heart to the lungs where it is oxygenated), the pulmonary veins (which bring oxygen-rich blood from the lungs to the heart), and the coronary …

The heart, blood and blood vessels work together to service the cells of the body. Using the network of arteries, veins and capillaries, blood carries carbon dioxide to the lungs (for exhalation) and picks up oxygen. From the small intestine, the blood gathers food nutrients and delivers them to every cell.

The cardiovascular system is made up of the heart and blood vessels. It circulates blood throughout the body. A healthy cardiovascular system is vital to supplying the body with oxygen and nutrients.

When the ventricles contract, atrioventricular valves close to prevent blood from flowing back into the atria. When the ventricles relax, semilunar valves close to prevent blood from flowing back into the ventricles.

When ventricular diastole occurs the ventricular pressure falls , closing the semilunar valves to prevent backward flow of blood to ventricles. Complete answer: A] valves in heart – these structures prevent backward flow of blood during contraction.

These openings are called valves because they open in one direction like trapdoors to let the blood pass through. Then they close, so the blood cannot flow backwards into the atria. With this system, blood always flows in only one direction inside the heart. They can squeeze (contract) to send blood rushing out.

A heart attack is also called a myocardial infarction (MI). It happens when one or more parts of the heart muscle don’t get enough oxygen. That occurs when blood flow to the heart muscle is blocked. If the blood and oxygen supply is cut off, muscle cells of the heart begin to suffer damage and start to die (infarct).

Cardiac muscle tissue is one of the three types of muscle tissue in your body. The other two types are skeletal muscle tissue and smooth muscle tissue. Cardiac muscle tissue is only found in your heart, where it performs coordinated contractions that allow your heart to pump blood through your circulatory system.

100 beats per minute.

Pacemaker Cells Phase zero is the phase of depolarization. This phase starts when the membrane potential reaches -40 mV, the threshold potential for pacemaker cells. There is the opening of voltage-gated Ca2+ channels on reaching the threshold, causing the influx of Ca2+ ions.

Cells within the sinoatrial (SA) node are the primary pacemaker site within the heart. Phase 4 is the spontaneous depolarization (pacemaker potential) that triggers the action potential once the membrane potential reaches threshold between -40 and -30 mV).

The action potentials of the pacemaker and contractile cells of the heart differ. The pacemaker cells have an unstable resting membrane potential. In the heart, the SA node is the fastest pacemaker cells and sets the rate of beating.

Further down the electrical conducting system of the heart is the Bundle of His. The left and right branches of this bundle, and the Purkinje fibers, will also produce a spontaneous action potential at a rate of 30-40 beats per minute, so if the SA and AV node both fail to function, these cells can become pacemakers.