"Heart" - what is it, definition of the term
The cardiac organ is a hollow, muscular structure situated in the thoracic cavity that functions as the primary pump of the circulatory system; it propels blood through a series of rhythmic contractions generated by the myocardium, delivering oxygen and nutrients to tissues while removing metabolic waste, and is divided into two atria and two ventricles, each lined with endocardium, encased by a protective pericardial sac, and regulated by an intrinsic electrical conduction network that coordinates its beating rhythm.
Detailed information
The cardiac organ is a muscular chamber that generates pressure to propel blood throughout the circulatory system. Its walls consist of three layers: an outer fibrous sheath, a middle muscular layer responsible for contraction, and an inner lining that minimizes friction. Electrical impulses originate in a specialized group of cells, travel through conductive pathways, and trigger coordinated muscle shortening, producing each heartbeat.
Blood enters the organ through two large veins, fills the atrial cavities, and then passes through valves into the ventricular chambers. Contraction of the ventricles forces blood into the arterial system, delivering oxygen and nutrients to tissues. Valves prevent backflow, ensuring unidirectional movement and maintaining efficient circulation.
Common pathogens transmitted by ectoparasites can impair cardiac function. Ticks may harbor bacteria that cause Lyme disease, which can lead to inflammation of the heart muscle and conduction abnormalities. Certain true bugs serve as vectors for Trypanosoma cruzi, the agent of Chagas disease, resulting in chronic dilated cardiomyopathy. Lice can transmit Rickettsia species that occasionally produce myocarditis. Fleas are associated with Bartonella infections, which have been linked to endocardial inflammation.
Key health impacts of these vector-borne agents include:
- Myocardial inflammation leading to reduced contractility.
- Arrhythmias caused by damage to the electrical conduction system.
- Structural remodeling that predisposes to heart failure.
Preventive measures focus on controlling ectoparasite exposure, employing protective clothing, using insect repellents, and maintaining environmental hygiene. Early diagnosis relies on serological testing and imaging studies that reveal functional impairment. Timely antimicrobial therapy can mitigate cardiac damage and improve prognosis.