Question

question 13
the heart valves that are located where the trunk of the pulmonary artery joins the right ventricle and where the aorta joins the left ventricle are called
semilunar valves.
atrioventricular valves.
venous valves.
cuspid valves.
question 14
the normal cardiac impulse that initiates mechanical contraction of the heart arises in the
av node.
av bundle.
purkinje fibers.
sa node.
question 15
atria are often called ______ because they receive blood from vessels called veins.
pumping chambers
venous chambers
deoxygenated chambers
receiving chambers

Explanation:

• Question 13: Semilunar valves are located at the exits of the ventricles (pulmonary valve at the junction of the right ventricle and pulmonary artery, aortic valve at the junction of the left ventricle and aorta). Atrioventricular valves (bicuspid and tricuspid) are between atria and ventricles. Venous valves are in veins. Cuspid valves are another name for atrioventricular valves.
• Question 14: The sino - atrial (SA) node is the natural pacemaker of the heart. It initiates the electrical impulse that leads to the mechanical contraction of the heart. The AV node, AV bundle, and Purkinje fibers are part of the conduction system but do not initiate the impulse under normal circumstances.
• Question 15: Atria receive blood (from veins). The term "receiving chambers" accurately describes their function. Pumping chambers refer to ventricles. Venous chambers is not a standard term. Deoxygenated chambers is incorrect as the left atrium receives oxygenated blood.

Answer:

• Question 13: semilunar valves
• Question 14: SA node
• Question 15: receiving chambers