Heart H.W study set

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SA node

1. pacemaker, initiates signal to contract by rhythmically depolarizing

AV node

2. delays signal so atria contract before ventricles

AV bundle

3. carries the signal to the ventricles, divides into left and right bundle branches down the interventricular septum

What valve disorder would result if the chordae tendineae connected to one of the cusps of the tricuspid valve were severed?

A valve prolapse would occur because the cusp would be pushed up into the right atrium. This causes valvular insufficiency since blood would flow back into the atrium instead of into the pulmonary trunk.The back flow of blood can be heart as a heart murmur.

What test can be done to detect blocked coronary arteries?

An angiogram (dye injected into the coronary arteries)

What happens if a coronary artery is blocked?

Cells die due to lack of oxygen. This is called a myocardial infarction or a heart attack.

What is the function of the coronary arteries and cardiac veins?

Coronary arteries carry oxygenated blood form the aorta to the cardiac muscle cells. Cardiac veins carry deoxygenated blood from cardiac muscle cells to the heart.

What is coronary heart disease?

Coronary heart disease is narrowing of the coronary arteries, often due to build up of fatty deposits in the wall of the arteries.

What can be done to prevent coronary heart disease or to treat it once it has occurred?

Lifestyle changes like exercise, healthy eating, not smoking, limiting alcohol, reducing blood pressure, and reducing stress can prevent coronary heart disease. Angioplasty, a stent or bypass can treat a blockage that has already occurred.

What are the molecules or features of the myocardium that allow carry on enough aerobic respiration to avoid fatigue?

Mitochondria -The myocardial cells contain lots of mitochondria (up to 25% of the cell's volume) to make ATP. Oxygen -The myocardial cells are supplied oxygen through the coronary arteries and many capillaries in the myocardium. The cardiac muscle cells contain myoglobin to store oxygen. Energy source -The myocardial cells contain glucose stored as glycogen and they can also use fatty acids and amino acids as sources of energy to make ATP.

What causes the first heart sound?

S1 -The closing of the AV valves at ventricular systole.

What causes the second heart sound?

S2 -The closing of the semilunar valves at diastole.

List the vessels, chambers, and valves through which the blood flows, in order. Begin with deoxygenated blood collected from the body and end with oxygenated blood flowing out into the body.

Superior and inferior vena cava ↓Right atrium ↓Tricuspid valve ↓Right ventricle ↓Pulmonary semilunar valve ↓Pulmonary trunk ↓Pulmonary arteries ↓Lungs ↓Pulmonary veins ↓Left atrium ↓Bicuspid/mitral valve ↓Left ventricle ↓Aortic semilunar valve ↓Aorta ↓Oxygenated blood to the tissues

What is the importance of the chordae tendineae attached to the cusps of the AV valves?

The chordae tendineae hold the cusps of the AV valves so that they are not pushed up into the atria during ventricular contraction

The AV valves have chordae tendineae, but the semilunar valves do not. Why don't semilunar valves need chordae tendineae?

The semilunar values don't have to stay closed against the force of ventricular contraction. They are closed by the pressure of the blood in the arteries when the heart relaxes and that pressure isn't strong enough to force the cusps to open the wrong way.

Why is important to have valves in the heart?

Valves keep the blood from flowing the wrong direction so that deoxygenated blood also moves toward the lungs and oxygenated blood moves toward the body.

nothing, there is a P wave, QRScomplex, and T wave for each beat; sinus rhythm