Which of the following stimulates the production of new erythrocytes?

A. The Bundle of His is the pathway that carries the electrical impulse from the AV node to the right and left bundle branches, which leads to the Purkinje fibers and ultimately causes the ventricles to contract.

B. The Purkinje fibers are the last component of the conduction system, responsible for rapidly transmitting the impulse to the ventricular muscle to trigger contraction, but the impulse must first travel through the Bundle of His.

C. The SA node is the natural pacemaker of the heart, initiating the electrical impulse, but the impulse does not travel to the SA node after the AV node. The SA node sends impulses to the atria first.

D. The bundle branches are part of the conduction system that transmits the electrical impulse to the Purkinje fibers. The impulse reaches the bundle branches after traveling through the Bundle of His.

A. Immunoglobulin G (IgG) is the most abundant antibody in the blood and plays a key role in the body's defense against bacterial and viral infections, but it is not directly involved in allergic reactions.
B. Immunoglobulin M (IgM) is the first antibody produced during an initial immune response, primarily involved in fighting infections, but it does not play a major role in allergic reactions.
C. Immunoglobulin E (IgE) is the antibody most directly involved in allergic reactions. When IgE binds to allergens, it triggers the release of histamine from mast cells, leading to the symptoms of allergies.
D. Immunoglobulin A (IgA) is primarily found in mucosal areas such as the respiratory and gastrointestinal tracts, where it helps prevent infections, but it is not directly involved in allergic responses.