1. Pulmonary circulation: Blood enters the top chamber on the right side at the right atrium via the superior vena cava, the inferior vena cava, and the coronary sinus opening. It flows into the right ventricle and when it contracts, blood goes through the pulmonary artery trunk and to the lungs to be oxygenated. Systemic circulation: Blood comes from the lungs via the pulmonary veins and enters the left atrium. The blood then travels to the left ventricle, and when it contracts, the blood is sent through the aorta and to cells, tissues, organs, and systems.
2. The SA node, AV node, AV bundles of His, and the bundle branches all work together to form the cardiac conduction system. This system generates and sends impulses through the heart to make the muscles depolarize and generate an action potential. This is what makes the heart pump and function.
3. A. sympathetic activity: increases cardiac output.
B. parasympathetic activity: depresses cardiac output.
C. epinephrine: increases cardiac output.
D. excess calcium: increases cardiac output by making contractions more efficient.
E. excess potassium: decreases cardiac output
F. fever: increases heart rate.
4. The tricuspid valve is located between the right atrium and right ventricle. It allows blood to flow down from the atrium, but prevents it from back flowing out of the right ventricle. The pulmonary semilunar valve is between the right ventricle and the pulmonary artery trunk. It allows blood to flow into the artery, but prevents it from leaking back into the right ventricle. The bicuspid valve is located between the left atrium and the left ventricle. It allows blood to flow down to the left ventricle, and prevents it from back flowing into the left atrium. The aortic semilunar valve allows the oxygen-rich blood to enter the aorta to be delivered throughout the body, but also prevents blood from leaking back into the left ventricle.