What are the main layers of the heart and their primary functions?

The main layers are the pericardium (protects and lubricates the heart), myocardium (muscle layer responsible for contraction), and endocardium (lines the heart chambers and valves, providing a smooth surface for blood flow).

Heart layers — components?

Pericardium, myocardium, endocardium.

How does the structure of the heart's layers relate to its function?

The pericardium anchors the heart and reduces friction; the myocardium's muscular structure enables effective contractions for blood pumping; the endocardium ensures smooth blood flow and prevents clot formation within the chambers.

Main vessels — types?

Arteries and veins.

What are the main structural components of vessel walls, and how do arteries and veins differ in their structure?

Vessel walls consist of an endothelium lining, a muscular layer, and an outer adventitia. Arteries have a thicker muscular layer to withstand higher pressure and maintain blood flow, while veins have a thinner muscular layer and often contain valves to prevent backflow.

Pulmonary vs systemic — circulation?

Pulmonary: lungs; systemic: body.