Final answer:
The heart's beating is initiated by the sinoatrial (SA) node, which is the pacemaker responsible for starting the sinus rhythm. The atrioventricular (AV) node then relays the signal to the ventricles. A gastroenterologist treats gastrointestinal diseases, such as Inflammatory Bowel Disease (IBD).
Step-by-step explanation:
The electrical signals that cause the heart to beat originate from the sinoatrial (SA) node. This structure is the heart's natural pacemaker and is responsible for initiating the sinus rhythm. The SA node is located in the right atrium and it sets off electrical impulses that spread to the atria causing them to contract. Subsequently, the signal travels to the atrioventricular (AV) node, where it encounters a brief delay, allowing the atria to finish contracting and the ventricles to fill with blood, before the signal is passed down through the bundle of His to the Purkinje fibers, prompting the ventricles to contract.
If you were seeing a gastroenterologist, a physician specializing in diseases of the gastrointestinal tract, you could potentially be diagnosed with Inflammatory Bowel Disease (IBD), which includes conditions such as Crohn's disease and ulcerative colitis.